SiteâSpecific Integrated Nutrient Management for Sustainable Rice ...

Site–Specific Integrated Nutrient Management for Sustainable Rice 

Production and Growth 

Dr. K.V. Rao, 

Principal Scientist (Soil Science) 

Directorate of Rice Research 

Rajendranagar, Hyderabad-30 

For more Information contact: Visit Rice Knowledge Management Portal http://www.rkmp.co.in 

Rice Knowledge Management Portal (RKMP) 

Directorate of Rice Research, 

Rajendranagar, Hyderabad 500030. Email: naiprkmp@gmail.com, pdrice@drricar.org, shaiknmeera@gmail.com 

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Introduction 

Crop management over the past four decades in India is driven by increasing use of 

external inputs. Fertilizers nutrients played a stellar role in improving crop productivity and 

production. During the period 1969-2010 food grain production more than doubled from about 98 

M. tons to 212 M. tons in 2001-02, while fertilizer nutrient use increased by > 12 times from 1.95 

M. tons to more than 23 M. tons in 2007-08. Notwithstanding these impressive developments, 

food grain demand is estimated to increase to > 300 M. tons per annum by 2025 for which the 

country would require about 45 M. tons of fertilizer nutrients (ICAR, 2008). With no scope for 

further increase in net cultivated area (~142 M. ha), much of the desired increase in food grain 

production has to be attained through productivity enhancement of major crops like rice, wheat, 

maize (contribute > 80% to total food production) by 3.0 to 7.5% annually (NAAS, 2006). Increasing 

genetic potential of genotypes, and more importantly improving use efficiency of resources and 

inputs like water, nutrients etc. through their efficient management involving conjunctive use of 

organic and inorganic sources and based on crop demand and location specificity are essential to 

economize input costs and improve factor productivity. The issue becomes more complex with 

increasing cropping intensity and cultivation of high yield potential cultures in view of the 

observed discouraging impacts of green revolution technologies on soil resource quality and its 

productivity. 

The growing concern about impaired soil health, declining / decelerating productivity growth 

and decreasing factor productivity or efficiency of the nutrients compelling to use increasing levels 

of fertilizers during the last two decades has raised apprehensions on the productive capacity of 

the agricultural system. The response to fertilizers use has decreased from 17 kg grain / kg 

nutrient in 1951 to 5-6 kg grains now, which ideally should be in the range of 18-25 kg/kg nutrient. 

Data from farmers’ fields (1999 – 2003) showed cereals responding around 8-10 kg grain /kg 

fertilizer (average). Traditional practices of organic manuring and growing of soil fertility restoring 

crops have gradually declined while nutrient outflows through crop production indicated an 

apparent negative balance of nearly 10 million tons at the national level, which is likely to increase 

to 16 million tons by 2012. The recovery efficiency of fertilizer nutrients is about 20-40, 15-20 and 





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40 -50% for N, P and K, respectively while for secondary and micronutrients it is substantially low 

ranging 5-12%. Major factors contributing to the low and declining crop responses to fertilizer 

nutrients are continuous nutrient mining from the soil due to imbalanced nutrient use (7:2.8:1 

NPK) leading to depletion of some of the major, secondary and micro nutrients like N, K, S, Zn, Mn, 

Fe, B etc., decreasing use of organic nutrient sources such as FYM, compost and integration of 

green manures / grain legumes in the cropping systems and mismanagement of irrigation systems 

leading to serious soil degradation qualitatively. Such decline in soil fertility status (due to negative 

balance of nutrients) is likely to end with irreversible damage to the nutrient supply system if 

followed further and could impact production costs with serous environmental consequences. 

Loss of soil organic carbon has been the important factor for the fatigue in agricultural 

production which has led to increased atmospheric CO 2 from 280 to 365 ppm over the years. 

Indian pool of soil organic carbon is estimated to be 21 billion tons in the top 30cm soil and nearly 

150 billion tons up to 150 cm soil depth (Pal et al., 2000). Technological options for soil C 

sequestration in India include INM, green manuring, mulch farming, conservation tillage, agro 

forestry / forestation, organic manuring, crop residue recycling and proper choice of cropping 

systems (Lal, 2004). The long-term fertilizer experiments in India have shown that balanced 

fertilization resulted in improved SOC status in the upper 42 cm soil by 8 t / ha at the rate of 0.25 t 

/ ha / year (Swarup, 2001). Carbon sequestration not only offsets rise in atmospheric carbon 

dioxide, but also improves the overall soil quality essential for sustainable crop productivity. 

Rice is the most important food crop of the country contributing nearly 45% to the total food 

grain production. The crop ranks first in the use of land (> 44 M. ha) and water resources (> 50% 

irrigation water), and inputs (38-40% of fertilizers and 17 – 18% of pesticides) though the use 

efficiency is considerably low. The crop is grown under diverse agro-ecological conditions in a 

variety of soils with wide range of soil characteristics, and depending on the resources and local 

choice, a wide array of crops are grown in sequence or inter cropped with varying productivity 

levels and certain inherent problems of nutrient availability and physical impairments. 





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Rice based cropping systems are the major production systems contributing to food 

production. Current crop production systems are characterized by inadequate and imbalanced use 

of fertilizers; blanket fertilizer recommendations over large domains with least regard to the 

variability in soil fertility and productivity. Future gains in productivity and input use efficiency 

require soil and crop management technologies that are tailored to specific characteristics of 

individual farms or fields. Recent on farm research demonstrated existence of large field variability 

in terms of soil nutrient supply, nutrient use efficiency, crop responses etc. Managing this 

variability is a principal challenge for further increasing crop productivity of intensive rice crop 

systems. Adoption of precision technologies for more efficient use of resources and nutrients 

becomes more relevant in the current production scenario. Site specific integrated nutrient 

management (involving use of inorganic /organic sources) taking into consideration spatial and 

temporal soil variability, nutrient requirements of the crops and cropping systems , soil capacity 

to supply nutrients, utilization efficiency of the nutrient and productive capacity of the varieties 

under best crop management strategies with improved nutrient use efficiency and without 

deteriorating soil and environmental quality is the most ideal system that needs to be practiced to 

achieve the targeted goals (Tiwari, 2007). 

Fertilizer Scenario 

India is third largest fertilizer consumer (23 M. tons in 2007-08), though the consumption is 

highly variable spatially. Out of 466 districts, 25% of total fertilizer use is consumed in 37 districts, 

50% in 102 districts and 75% in 202 districts. In 65% of districts less than 100 kg nutrients / ha are 

used, 100-200 kg/ha in 28% of districts and more than 200 kg/ha in only 7 per cent of districts. 

Consumption ratio of primary plant nutrients (NPK) also shows large variability at district, state 

and regional levels (FAO, 2005). Over the time NPK ratio at the national level narrowed down 

from 8.9:2.2:1in 1961/62 to 5.9:2.4:1 in 91/92 but after decontrol the ratio widened to 9.7:2.9:1 in 

93/94 and currently it is around 6.9:2.6:1 (2003-04). The consumption of nutrients in the north 

zone is acutely skewed towards N in relation to K (103:32:5.3 kg NPK/ha) compared to south and 





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east zone (60:26:19 and 49:16:11 kg NPK/ha, respectively) while at the state and district levels the 

problem is more serious. 

The total fertilizer used in India by five crops (rice, wheat, sugarcane, cotton, rapeseedmustard) 

account for 68%. Major share is accounted for paddy (37%) and wheat (24%) among 

food crops. On an average farmers applied 126 kg/ha of NPK to rice in 2001-02 in the ratio of 4.3: 

1.7: 1 and 132 kg/ha in the ratio of 24:10:1. In irrigated areas it was about 165 kg/ ha for paddy 

and 143 kg NPK/ha for wheat (96-98%). Under rice-wheat cropping system, the per-hectare 

consumption of nutrients in the IGP on an average is about 334 kg (range 258 to 444 kg) 

approximately @ 118, 36 and 11 kg/ha for each crop which show a decreasing trend from 

northwest to east of IGP. 

Nutrient demands for crop production 

Sustainable management involves replenishing of nutrients that are harvested with crops 

while taking into the consideration other net influxes of nutrients. Indian agriculture is operating 

at an estimated negative nutrient balance of 10 M. tons. Trends in nutrient use of 23 M tons in 

2007-08 is expected to increase to 29 .0 M tons (20.7 N, 6.8 P 2 O 5 and 2.1 K 2 O M. tons) by 2025. 

However, at the estimated nutrient removal of 37.5 M. tons of NPK (11.9 N + 5.3 P 2 0 5 + 20.3 K 2 O 

M. tons), the balance indicate an excess use of N and P 2 O 5 and deficit use of nearly 18 M tons of 

K 2 O nutrients which would be alarming. Potassium accounts for 55% of NPK removal, while N and 

P accounts for 31 and 14% of crop uptake (Tiwari, 2009). To achieve the projected food grain 

demand of 300 M. tons by 2025, about 30 M. tons of NPK from various sources are required in 

addition to 15 M. t. for the commercial crops (total 45 M. t.). 





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Nutrient uptake by crops and cropping systems 

Knowledge of nutrient removal under intensive cropping systems is important for 

developing future nutrient management strategies. Substantial variation occurs in the nutrient 

uptake by crops and cropping systems. Rice – Wheat - Cowpea fodder system removes about 270 

kg N/ha, 150 kg P 2 O 5 /ha and 390 kg K20/ha (total > 800 kg/ha). Annual removals of NPK could 

range from 440 - 815 kg/ha under high intensity cropping systems. Production of about 8-12 tons 

of grain/ha is associated with nutrient uptake of 140-330 kg N, 70-120 kg P 2 O 5 /ha and 200-390 kg 

K 2 O/ha which provides guidelines for framing nutrient management strategies. Needless to 

mention that the nutrient needs of individual crops in space and time vary considerably, while the 

efficiency of soil and applied fertilizer nutrients largely depend on the quality of crop management 

and farmer’s resources. Harnessing synergistic nutrient interactions operating at higher levels at 

crop productivity is vital for achieving high productivity targets. For e.g. rice yield could be raised 

from 4.3 to 6.0 t/ha by extra dose of potassium. Similarly the response ratios to K applications at 

graded level of N increased for each increment indicating positive N – K interaction. The responses 

to P application can also be increased with increasing supply of K while the efficiency of zinc 

increased with K applied @ 60 kg/ha by more than double from 500 kg/ha to nearly 1200 kg/ha 

(Tiwari, 1999) 

The nutrient requirement of the crops yielding 3.5 t/ha will be certainly be much less (52 N, 

29 P 2 O 5 and 83 K 2 O and 20 kg S) than crops targeted to yield 9.5t/ha (218N, 71 P, 309 K and 80 S). 

Depending on nutrient removal and soil nutrient supply, the difference has to be supplied through 

fertilizer at the efficiency with which the fertilizer nutrient is absorbed by the crop as determined 

by the genotype and quality of crop management. Achieving high yield targets are possible only 

when correct amount of nutrients is supplied at the right time matching with the crops nutrient 

demand during the season. Efficient nutrient management strategy should aim at maximizing crop 

uptake of nutrients, utilize crop residues /manures, and adopt good crop management strategies 

while correcting specific nutrient limitations through use of mineral fertilizers. 





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Achieving high yield goals 

The potential yields of crops in irrigated system have not yet been realized in India. Most 

farmers achieve less than 60% of climatic and genetic yield potential at a particular site. For most 

of the rice growing environments in tropical south and south east Asia, the currently grown high 

yielding rice varieties has maximum yield of 10.0 t /ha in the dry season and 7- 8 t/ha in wet 

season. Attainable yields with the best management is about 75-80% of climatic yield, depending 

on the environment, which can be the target for the farmers who generally realize about 20% less 

than the highest realizable yields. Understanding such yield gaps is important as it gives scope and 

opportunities for improvement by efficient nutrient management. 

Nutrient use efficiency (NUE) 

The topic of nutrient use efficiency has recently gained more attention with rising 

fertilizer costs and continued concern over environmental impairment. Nutrient or fertilizer use 

efficiency can be viewed from different perspectives based on yield, recovery or removal. Among 

the most common expressions of efficiency is the recovery efficiency (RE) of fertilizer nutrient, 

defined as the percentage of fertilizer recovered in aboveground plant biomass during the growing 

season. Fertilizer utilization rate (crop recovery efficiency) under favourable conditions for N is 

about 50-70%, 10-25% for P (15% average), and 50-60% for K. It was also suggested that efficiency 

of P and K over time (multiple growing seasons) could also be taken into account for realistic 

estimate. Nutrients that build-up in soil such as P and K, can certainly be viewed over the long 

term, while N efficiency is viewed on the short term because of its transient nature. Where there 

is potential for building soil C reserves, long term N efficiency is appropriate because soil C balance 

also affects N balance’ 

Reasons for low NUE: 

Nutrient losses – Erosion, leaching, runoff, volatilization, denitrification etc. 

Soil fixation of nutrients – P in deficient, highly weathered acid soils (Ultisols and Oxisols), K 

in highly illitic clay soils and Zn in high clay and calcareous soils. 





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Nutrient interactions - antagonistic interactions between P and Zn, Na and K, Mg and K, Ca 

and K, Ca and Fe etc. 

Imbalanced fertilizer use - imbalanced use of a few straight fertilizers results in reduced 

availability of other nutrients there by reducing their use efficiency. 

Soil related problems - acidity, salinity; alkalinity, calcareous, acid sulphate soils, poor 

drainage, texture etc. result in poor availability of nutrient elements. 

Non – nutrient factors such as lodging, untimely planting, and pest / disease problems limit 

NUE. 

Strategies to improve NUE 

Judicious use of fertilizer through soil test based approach, fertilization based on nutrient 

balance (i.e. total Inputs - total outputs; mineral fertilizer, organic manure, atmospheric 

deposition, biological N fixation, irrigation, rice seedlings, wheat seeds and root biomass are the 

main sources of nutrient inputs, and nutrients removed through crop uptake, leaching and 

gaseous / erosion losses of fertilizer and soil nutrients are outputs), water management, selection 

of variety, crop rotations (nitrate catch crops, N fixing grain legumes, green manures, deep root 

crops etc), new forms of fertilizers (controlled release coated fertilizers, urease or nitrification 

inhibitors, incorporation of other essential nutrients, granulation, liquid and suspension forms, 

chelated forms), precision farming, Integrated nutrient management (INM/IPNS), use of microbial 

sources(bio fertilisers such as Azolla, Cyanobacteris, Azospirillum, Rhizobium, Azorhizobium, 

Acetobacter and other heterotrophic N 2 fixing bacteria, leguminous green manures, phosphate 

solubilizing bacteria etc), demand driven nutrient application (especially for N chlorophyll meter / 

LCC based N application), conservation agriculture, fertigation, site-specific Nutrient Management 

(SSNM), computer based decision support systems etc, 

Spatial variability: 

Spatial and temporal variability is inherent to agricultural production systems. Land characteristics 

especially native nutrient content varies spatially, recognition of which is essential for SSNM. Lack 

of recognition of such variability among agricultural holdings has given rise to a kind of blanket 





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ecommendations of fertilizer nutrient use over large domains. Any deficit application of fertilizers 

will limit crop yields, facilitate nutrient mining and result in depletion of soil fertility. Excessive or 

imbalanced application not only wastes limited resources but also has the potential to pollute the 

environment. An approach towards mitigating such concern is site specific nutrient management 

(SSNM), which takes into account spatial variations in the landscape. 

Use of GPS and GIS systems: Wide spread adoption of SSNM technologies based on soil testing 

require extensive soil sampling and analysis which could be a hindrance considering the available 

infrastructure. Use of Global Positioning system (GPS) and Geographical Information System (GIS) 

and mapping can provide the right support as cost effective alternative. Studies conducted under 

AICRIP in UP, West Bengal and Assam indicated significant variations on crop responses, soil 

nutrient supplies, nutrient uptake, rice productivity and nutrient use of efficiency with sufficient 

yield gaps between farmers’ practices and recommended fertilizer dose (Tables1-2). Studies on 

such spatial variability in farmer’s fields are limited. Jat et al (2002, 2003) concluded that the 

differential responses in irrigated rice systems were associated with spatial variability in soil 

properties. Later studies (Pal et al 2003) observed wide variability of soil chemical properties 

which significantly influenced crop yields. Similar works on soil physico-hydrological properties in 

watersheds benefited the productivity through increased crop intensity (Kar et al 2004). Recently, 

Sen et al (2008) documented wide spatial variability in the available nutrient status of soils on 

small areas in West Bengal (Table 3). 

Table 1 Variability in soil nutrient supply in farmers’ fields in Assam and UP under rice, kharif, 

2006 

Nutrient omitted Titabar, Assam Ghagraghat, UP 

Range Mean* Range Mean** 

Grain yield (t/ha) 

(-) N 2.7-5.7 4.1 3.5-5.0 4.1 





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(-) P 3.0-5.5 4.2 3.8-5.0 4.5 

(-) K 2.9=5.1 4.1 4.5-6.2 5.1 

C.D. (0.05) - 0;1 - 0.05 

F ratio for sites - 46.3 - 157.7*** 

Soil test value (kg/ha) 

Nutrient Range Mean Range Mean 

N (OC, %) 1.0-1.5 1.2 105-236 162 

P2O5 13-23 17 8-25 15 

K2O 57-142 97 145-250 184 

* Mean of 12 farm sites ** Mean of 20 farm sites *** Significant (0.01) 

Ref: DRR Progress report 2006 (2007) 

Table 2 Variability in soil nutrient supply in farmers’ fields, kharif, 2006 

Nutrient uptake (kg/ha) 

Nutrient Titabar Ghagraghat 

Range Mean Fratio for sites CD 

(0.05) 

Range Mean Fratio for 

sites 

CD (0.05) 

N 36-59 48 16.3 3.1 54-80 68 36.7** 1.8 

P2O5 10-18 14 9.5 1.3 19-23 20 20.4** 0.6 

K2O 37-61 49 13.3 4.0 90- 

124 

106 66.5*8 1.5 

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** Significant (0.01), DRR Progress report 2006 (2007) 

Table 3 Variability in soil properties in Murshidabad district, West Bengal under RBCS 

Soil parameter Minimum Maximum Mean SD CV (%) 

pH 6.8 7.9 7.4 0.3 4 

EC (dS/m) 0.1 0.7 0.4 0.2 58 

OC (%) 0.2 1.1 0.7 0.2 25 

Total N (%) 0.02 0.09 0.06 0.01 24 

Avail. P2O5 (kg/ha) 50.4 366 194 98.7 51 

Avail. K2O (kg/ha) 87.0 448 254 93.0 37 

(Sen et al., 2008) 

Site specific integrated nutrient management 

Concept: Nutrient Management and recommendation process in India is still based on response 

data arranged over large domains. The SSNM provides an approach for need based feeding of 

crops with nutrients while recognizing the inherent spatial variability. It involves monitoring of all 

pathways of plant nutrient flows / supply, and calls for judicious combination of fertilizers, bio 

fertilizers, organic manures, crop residues and nutrient efficient genotypes to sustain agricultural 

productivity. It avoids indiscriminate use of fertilizers and enables the farmer to dynamically adjust 

the fertilizer use to fill the deficit optimally between nutrient needs of the variety and nutrient 

supply from natural resources, organic sources, irrigation water etc. It aims at nutrient supply at 

optimal rates and times to achieve high yield and efficiency of nutrient use by the crop. SSNM 

approach involves three steps – establishing attainable yield targets, effectively use existing 





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nutrient sources and application of fertilizers to fill the deficit between demand and supply of 

nutrients. 

Soil nutrient supply potential and its spatial variability, productivity potential and targets for crops 

and cropping systems, estimation of nutrient requirements, and fertilizer use efficiency besides 

assessment of resource quality and socioeconomic background of the farmers are essential for 

developing site specific IPNS. The soil, crop, nutrient and resource related parameters that are 

essential for suggesting and practicing site specific IPNS include: 

• Soil testing – nutrient supply potential 

• Productivity targets of crops and cropping systems and nutrient needs- each ton of grain 

removes about 82 kg nutrients which do vary with crops and productivity, 

• Efficiency of nutrient sources- fertilizers organic nutrient sources like FYM, green manures, 

• composts, bio fertilizers, organic industrial wastes and soil amendments 

• Nutrient efficient genotypes 

• Selection of suitable crops and cropping systems involving N fixing crops and their 

management 

• Correction of soil and nutrient related problems 

Soil test based nutrient management: 

Evaluation of soil fertility and making fertilizer prescriptions for sustained crop production is of 

importance to the farming section. Considerable progress has been made to understand the 

contribution of soil and fertilizer to crop nutrition and the influence of nutrient levels and 

management on crop productivity and nutrient use efficiency. Soil testing to assess the nutrient 

supply capacity provided an opportunity for practical solutions to nutrient management. Soil test 

based recommendations will be useful only when it is based on important factors like soil, crop, 

variety, fertilizer and management interaction for a given soil condition. The soil test based crop 

response (STCR) project of ICAR provided the right impetus to understand the variability in the soil 

and crop with practical solutions to enhance nutrient use efficiencies narrowing down to each 

farm or field. 

The on-farm trials provided further need and scope for refinement, and 

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development of more efficient soil test methodologies and decision support systems for adoption 

at all levels of technology transfer. Several models to predict changes in soil test values under a 

given environment were also developed. While the results for irrigated dry and rainfed crops 

were encouraging, in crops like wet land rice, soil test based fertilizer recommendation could not 

be that successful because of the unique system and chemistry that influenced soil nutrient 

availability. 

Modern approaches of fertility evaluation mainly focused on increasing the fertilizer use 

efficiency. In many approaches, yield of crop is related to fertilizer response and soil test value 

which is expressed as - 

Yield = f (crop, soil, climate and management) 

Few details of some of these approaches are elucidated below: 

1. Soil analysis and correlation approach: Conducting pot culture studies, yield responses plotted 

against soil test values and soils grouped into low, medium and high. In this concept, it is not 

possible to indicate how much fertilizer to be added to get economic response. 

2. Agronomic approach: Based on field crop response trials with graded nutrient levels on 

farmers’ fields optimum levels of nutrients are worked out (AICARP) 

3. Soil fertility cum soil survey approach: Information of soil fertility and soil survey would be 

considered for making fertilizer recommendations based on soil units such as series, association 

and types. This is an improved method over agronomic approach. 

4. Critical soil test level approach: This approach is mainly for less mobile nutrients like P and K 

and is widely accepted and known as International Soil Fertility Evaluation and Improvement 

Programme. The technique involves screen house studies, critical limit determination and 

ultimately field verification trials. 

5. Mitscherlich and Bray approach: This approach involves 3 mathematical expressions – linear, 

exponential, quadratic model. The latter two are applicable to immobile nutrients such as P, K, Ca 





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and Mg while linear model is applicable to mobile nutrients such as nitrates and borates. 

Biologically, exponential expression has merit over others. Exponential never reaches maximum 

and fail to indicate toxic level or decrease in yield due to excess nutrients. Straight line function is 

best fit for high fertile soils. 

6. Foliar diagnostic approach: This method can be used as a supplementary to soil testing. Tissue 

tests are performed on cell sap which has limitations. Most plant recommendations are based on 

critical level of sufficiency 

7. Budget method approach: It involves four steps - Estimation of potential yield from plant 

available water status, calculation of N needed to obtain that yield, soil N inventor and calculation 

of N fertilizer rate. This method is used for recommending fertilizer N for dry land farming. 

8. Basic cation saturation ratio approach: For optimum crop growth best ratio of basic cations 

and best total base saturation are assessed. The steps are selection of cation base saturation on 

ratios, estimation of CEC and estimation of Ca, Mg and K requirement. 

9. Inductive Approach: This approach aims at eliminating influence of the three of the four 

factors in the yield equation, viz. crop, climate and management by choosing one field over 

which elaborate treatments are super-imposed to obtain crop responses for correlating with 

soil test values artificially created by differential fertilizer treatments. From the statistically 

significant multiple regression equations, simple relationships between soil test and fertilizer 

doses are derived for maximum and economic yields. These results can be extended to soils 

of similar nature. 

10. Targeted Yield Approach: It established the theoretical basis and experimental proof to 

Truog's (1960) concept of fertilizer prescription for desired crop yields based on available 

nutrient status of the soil. The basis is that for obtaining a given yield, a definite quantity of 

the nutrients must be taken up by the crop. Once this requirement is known for a given 

yield, the requirement of fertilizer can be estimated taking into account the efficiency of soil 

available nutrients and that of the fertilizer nutrient. 





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11. Integrated Approach for Soil Test Crop Response Correlation: It is well recognized that 

physical, chemical and biological characteristics of soil besides available nutrients also affect 

the crop yields for improving the interpretation. This concept is of special significance in 

making fertilizer recommendations for compacted soils, saline soils and for dry farming 

conditions. 

12. Sufficiency Levels of Available Nutrient Approach: This concept is based on a general 

mathematical expression of the law of diminishing returns where increase in yield of a crop 

per unit of available nutrient decreases as the level of available nutrient approaches 

sufficiency. This approach 

implies that (i) levels of available nutrients range in a group of soils from insufficiency to 

sufficiency for optimum growth of plants, (ii) that amounts of nutrients removed by suitable 

extractants will be inversely proportional to yield increases from added nutrients, and (iii) that 

calibrations have been made for changing the levels of available nutrients in the soil by adding 

fertilizer. 

13. Targeted Yield Approach and Crop Production Strategies: The targeted yield concept can 

be effectively used for making general food grain production projection for increased and 

efficient fertilizer use. It has been reported that high response ratio (response yardstick) 

was obtained from targeted yield follow up trials due to the value of soil testing in 

enhancing fertilizer use efficiency. The average response ratio obtained by them from 

these trials was 17.8 for fertilizer use based on soil testing and 9.8 for fertilizer use based 

on general recommendation. 

14. Soil test based fertilizer recommendation for fixed cost of investment: Targeted yield 

based fertilizer recommendations can be more effectively made for a farmer based approach. 

15. Fertilizer recommendation for targeted yield and maintenance of soil fertility: 

Maintenance of soil fertility can easily be attained by choosing appropriate yield targets and 

fertilizer use practices 





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16. Integrated approach for soil test crop response correlation: By quantifying the physical 

properties, available soil moisture and other such soil parameters along with soil test values, 

the reliability of soil test interpretation can be further enhanced. It was observed that yield 

predictions improved when physical parameters such as clay content, bulk density, oxygen 

diffusion rate and resistance to penetration were considered along with available nutrients in 

the model. The utility of such concept is of special significance in making fertilizer 

recommendations for compacted soils, saline soils and for dry land farming. 

In a recent review of STCR based fertilizer recommendations Naidu et al (2008) indicated 

that because NARP Agro climatic zones were geographically larger with highly 

heterogeneous in soils, rainfall pattern and length of cropping seasons, NARP zone based 

recommendations were very generalized and were not soil specific. Zonal N and P 

recommendations were more than the STCR based requirements while K recommendations 

were lower. Cost of imbalanced nutrient applications ranged from Rs. 45 to (-) 1162 and 

Rs.2240 to (-) 3500, respectively when compared against NARP recommendations and 

farmer’s practice. This suggested for refinement in of soil based fertilizer recommendations, 

emphasizing balanced application of K and micronutrients, and to initiate large-scale 

technology transfer activities. The STCR target yield fertilizer prescription equations 

developed by the All India Coordinated Programme for rice suitable for respective states and 

districts are presented in the Table 4 which indicate about the variability in the level of 

fertilizer nutrients to be applied, soil nutrient supply and yield targets. 

Table 4 Prescription equations for yield target based fertilizer recommendations for rice and rice 

based cropping systems in India (AICRP on STCR) 

District/ State 

Seaso 

Soil Variety Target 

Fertilizer prescription equation 

n 

yield 

FN FP FK 

(t/ha) 

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Guntur, 

Vijayawada 

and Ongole: 

Kharif 

Clay 

Mashur 

i 

5.0 -5.5 

3.79 T – 

0.50 SN, 

3.19 T – 

3.17 SP, 

1.60 T – 0.19 

SK 

KarimnagarK 

hammam, 

Nizamabad, 

Kharif 

Sa.l, Chalka 

Pothan 

a 

5.0 -6.0 

3.78 T – 

0.44 SN, 

1.96 T – 

2.13 SP, 

2.96 T – 0.36 

SK 

Adilabad 

East and 

West 

Godavari and 

Alluvial 

(Heavy) 

- 6.0 

.30 T – 

0.32 SN, 

1.91 T – 

1.90 SP, 

2.27 T – 0.27 

SK 

Krishna 

Kurnool, 

Anantapur & 

Cuddapah 

Black soils - 7.0 

3.35 T – 

0.33 SN, 

2.52 T – 

4.53 SP, 

1.24 T – 0.12 

SK 

Nellore, 

Ongole, 

Tirupati and 

Sandy cl.l 

NLR- 

9672 

4.5 – 5.0 

3.47 T – 

0.37 SN, 

2.53 T – 

2.12 SP, 

1.89 T – 0.20 

SK 

Cuddapah: 

R’nagar 

Jadcherla, 

Sanga Reddy 

Kharif, 

Light black 

soil 

Tellaha 

msa 

5.0-5.5 

4.20 T – 

0.55 SN, 

2.70 T – 

2.67 SP, 

2.22 T – 0.21 

SK 

and Nalgonda 

Warangal, 

Karimnagar, 

Black soil Pothan 5.0– 5.5 

4.75 T – 

0.75 SN, 

2.75 T – 

4.20 SP, 

1.99T – 0.15 

SK 

Page | 17 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Nizamabad, 

Adilabad 

a 

Warangal, 

Karimnagar, 

Nizamabad, 

Rabi 

Black soil 

Tellaha 

msa 

5.0 – 5.5 

2.83 T – 

0.32 SN, 

2.29 T – 

2.98 SP, 

1.34 T – 0.17 

SK 

Adilabad 

Nellore, 

Chittoor, 

Cuddapah 

and 

Rabi 

Alluvial soils 

NLR 

33057 

4.5– 5.0 

4.53 T – 

0.51 SN, 

2.12 T – 

2.06 SP, 

2.35 T – 0.21 

SK 

Prakasam 

Maruteru(Eas 

t and West 

Godavari and 

Krishna 

Rabi, Alluvial IR-64 7.0 

2.65 T – 

0.28 SN, 

2.00 T – 

2.16 SP, 

1.96 T – 0.21 

SK 

district) 

Rajendranaga 

r Nalgonda, 

Mahaboobna 

gar and 

Rabi 

Light black 

soil 

Tellaha 

msa 

7.0 – 8.0 

3.23 T – 

0.26 SN, 

1.51 T – 

1.80 SP, 

1.65 T – 0.16 

SK 

Medak 

Warangal, 

Karimnagar, 

Nizamabad 

Rabi 

Black soil 

Pothan 

a 

6.0 

3.97 T – 

0.50 SN, 

2.65 T – 

3.52 SP, 

1.51 T – 0.08 

SK 

Page | 18 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

and Adilabad 

Nellore, 

Ongole, 

Tirupati and 

Cuddapah 

kharif 

Sandy clay 

loam 

NLR- 

9672 

8.0 

3.43 T – 

1.45 SN- 

0.70 FYM 

N 

3.43 T – 

1.45 SN- 

0.65 GM N 

1.30 T – 

4.83 SP- 

0.43 FYM 

P 

1.30 T – 

4.83 SP- 

0.38 GM P 

1.93 T – 0.56 

SK- 0.104 

FYM K 

1.93 T – 0.56 

SK- 0.14 GM 

K 

Nandyal, 

3.36 T – 

Ongole, 

Kurool and 

Cuddapah 

kharif 

Black soil 

MTU 

5182 

6.0 

0.33 SN- 

0.74 FYM 

N 

3.36 T – 

2.53 T – 

4.53 SP 

0.81FYM P 

2.53 T – 

1.42 T – 0.12 

SK- 0.15 FYM 

K 

1.42 T – 0.12 

0.33 SN- 

4.53 SP- 

SK- 1.09 GLM 

1.62 GLM 

1.30 GLM P 

K 

N 

Raga Reddy 

4.20 T – 

2.7 T – 

and 

Mahabubnag 

ar districts 

Kharif 

black soil 

Tella 

hamsa 

7.0 

0.55 SN- 

0.74 FYM 

N 

4.20 T – 

2.67 SP- 

0.81 FYM 

P 

2.7 T – 

2.22 T – 0.21 

SK- 0.15 FYM 

K 

2.22 T – 0.21 

0.55 SN- 

2.67 SP- 

SK- 1.09 GLM 

1.62 GLM 

1.30 GLM 

K 

N 

P 

Page | 19 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Nizamabad 

3.79 T – 

0.50 SN- 

3.19 T – 

Kharif, Black soil 6.0 

0.43 FYM 

N 

3.79 T – 

0.50 SN- 

0.94 GLM 

N 

3.17 SP- 0. 

3.19 T – 

3.17 SP- 

1.38 GLM 

P, 34 FYM 

P 

1.60 T – 0.19 

SK- 0. 1.60 T 

– 0.19 SK- 

1.38 GLM K 

E.Godavari & 

Krishna 

Godavari 

Zone 

Kharif 

Alluvial, clay 

MTU- 

2067 

7.0-8.0 

2.30 T – 

0.32 SN- 

0.74 FYM 

N 

2.30 T – 

0.32 SN- 

0.57 GLM 

N 

1.91 T – 

1.90 SP- 

0.36 FYM 

P 

1.91 T – 

1.90 SP- 

2.43 GLM P 

2.27 T – 0.27 

SK- 0.29 FYM 

K 

2.27 T – 0.27 

SK- 1.35 

GLM K 

4.75 T – 

North 

Telangana 

Zone 

Kharif 

Black soil 

Pothan 

a 

Up to 7.0 

0.75 SN- 

0.76 FYM 

N 

4.75 T – 

0.75 SN- 

2.75 T – 

4.20 SP- 

0.34 FYM P 

2.75 T – 

4.20 SP- 

1.99 T – 0.15 

SK- 0.34 FYM 

K 

1.99 T – 0.15 

SK- 1.31 GLM 

1.45 GLM 

2.51 GLM P 

K 

N 

Page | 20 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Tamilnadu 

Coimbatore 

Kharif 

Alluvial 

(Noyyal 

series) 

IR 50 6.0 

4.39T- 

0.52SN- 

0.80ON 

2.22T- 

3.63SP- 

0.98OP 

2.44T-0.39SK- 

0.72OK 

Coimbatore 

Rabi 

Alluvial 

(Noyyal 

series) 

IR 20 6.0 

4.63T- 

0.56SN- 

0.90ON 

1.98T- 

3.18SP- 

0.99OP 

2.57T-0.42SK- 

0.67OK 

Bhavanisagar 

Kharif 

Red sandy 

loam 

IR 50 6.0 

5.19T- 

0.89SN- 

0.98ON 

2.27T- 

4.50SP- 

1.09OPF 

3.11T-0.59SK- 

1.02OK 

Bhavanisagar 

Rabi 

Red sandy 

loam 

ASD 18 5.0 

4.88T- 

0.68SN- 

0.72ON 

2.06T- 

2.91SP- 

2.27OP 

2.89T-0.47SK- 

0.59OK 

Aduthurai 

Kharif 

River 

Alluvium - 

Clay loam 

(Adanur 

CR 

1009 

7.0 

0.89ON 

1.78OP 

2.80T- 

0.29SN- 

1.35T- 

1.28SP- 

2.50T-0.42SK- 

1.14OK 

series) 

Aduthurai 

Kharif 

River 

Alluvium - 

Clay loam 

(Kalathur 

ADT 31 6.0 

5.29T- 

0.75SN- 

0.89ON 

1.65T- 

1.76SP- 

0.78OP 

2.73T-0.37SK- 

0.82OK 

series) 

Aduthurai 

Rabi 

River 

Alluvium - 

ADT 31 6.0 

5.34T- 

0.67SN- 

1.90T- 

1.86SP- 

2.81T-0.33SK- 

Page | 21 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Clay loam 

(Kalathur 

series) 

0.73ON 0.70OP 0.80OK 

Killikulam 

Kharif 

River 

Alluvium - 

Sandy clay 

loam 

ASD 16 

6.0 

0.79ON 

0.89OP 

4.25T- 

0.60SN- 

2.71T- 

4.39SP- 

3.83T-0.60SK- 

0.82OK 

Killikulam 

Rabi 

River 

Alluvium - 

Sandy clay 

loam 

IR 20 6.0 

0.79ON 

0.89OP 

4.47T- 

0.58SN- 

2.66T- 

3.68SP- 

4.08T-0.65SK- 

0.82OK 

Palampur 

- 

Mid hills-wet 

temperate 

zone 

- 4.0 

5.46 T - 

0.32 SN 

2.50 T - 

2.67 SP 

2.82T - 0.68 

SK 

Raipur 

5.8 

Kharif Alfisol IR 36 4.0-6.0 

8 Y 

– 

0.8 

8 

SN, 

107 - 

(11439 – 

202.5Y) 1/2 

– 4.13 SP 

No K if SK 

>250 kg ha -1 

Raipur 

Kharif Vertisol Indira 9 3.5-4.5 

3.65 Y – 

(0.489 SN + 

5.12 t 

129 – 

(16710- 

244Y) 1/2 – 

No K if SK 

>250 kg ha 

Page | 22 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

FYM) (2.89SP + 

3.0 t FYM) 

Raipur 

Kharif 

Inceptisol 

Maham 

aya 

4.0-6.0 

3.93 Y – 

0.489 SN 

110 - 

(12195 – 

205Y) 1/2 – 

No K if SK 

>250 kg ha -1 

2.11 SP 

Karnataka 

Bangalore, 

Kolar and 

Tumkur 

Kharif 

Red lateritic 

Jaya 

and 

HYVs 

- 

7.26 T - 

129 SN (OC 

%) 

4.05 T - 

2.52 SP 2 O 5 

(Olsen’s - 

P 2 O 5 ) 

3.15 T - 0.29 

SK 2 O (NH 4 

OAC - K 2 O) 

Mandya and 

Mysore 

Kharif Red Rasi - 

4.703 T– 

274.865 SN 

(OC %) – 

0.00141 

OM 

1.636 T– 

0.2563 

SP 2 O 5 

(Olsen’s - 

P 2 O 5 ) – 

0.00077 

2.306 T– 

0.494 SK 2 O 

(NH 4 OAC - 

K 2 O) – 

0.00114 OM 

OM 

Ludhiana 

Kharif 

Alluvial 

HYV - 

4.39 T-1.50 

SN 

5.08 T – 

1.74 SN- 

0.81 

FYM_N 

0.67 T-0.26 

SP 

1.39 T- 

0.55 SP – 

0.51 

FYM_P 

0.88 T – 0.23 

SK 

1.22 T- 0.32 

SK- 1.20 

FYM_K 

Page | 23 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Delhi state 

a 

n 

d 

adj. soil-agro 

climatic areas 

Kharif 

Typic 

hapusttept 

HYV - 

4.93 T – 

0.47 SN 

4.48 T – 

7.82 SP 

2.31 T – 0.21 

SK 

of UP, MP, 

Haryana, 

Punjab, and 

Rajasthan 

Maharashtra 

Kolhapur, 

Sangli, Satara 

Kharif 

Typic 

Haplustepts 

R-24 3.0-4.0 

5.52 T – 

0.54 SN 

2.19 T – 

0.83 SP 

2.37 T – 0.05 

SK 

Nasik, Pune, 

Nandurbar, 

Gadchiroli, 

Kharif 

Typic 

Ustorthents 

Indraya 

ni 

4.0-4.5 

5.20 T – 

0.34 SN 

9.40 T – 

13.66 SP 

2.73 T – 0.16 

SK 

Kolhapur 

Bihar. 

Pusa 

Kharif 

calcareous 

soils 

HYV 4.0 

6.82 T – 

0.53 SN – 

3.60T – 

2.16 SP 2 O 5 

3.42 T – 0.39 

SK 2 O – 0.36 

Page | 24 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

(Samastipur) 0.77 CN – 1.05 

CK 2 O 

CP 2 O 5 

Pusa 

Kharif 

Young 

Alluvium 

Calcareous 

HYV 4.0 

5.60 T – 

0.40 SN, 

3.30 T – 

2.48 SP 2 O 5 

3.31 T – 0.65 

SK 2 O 

Soil 

Pusa 

Recent 

Kharif 

Alluvium 

Non Calc. 

Non Saline 

HYV - 

4.91 T – 

0.31 SN, 

2.74 T – 

2.54 SP 2 O 5 

2.28 T – 0.39 

SK 2 O 

Soil 

Pusa 

Kharif 

Old Alluvium 

Light 

Textured Soil 

HYV - 

4.54 T – 

0.39 SN 

2.73 T – 

2.92 SP 2 O 5 

1.85 T – 0.24 

SK 2 O 

Pusa 

Kharif 

Old Alluvium 

Heavy 

Textured Soil 

HYV - 

4.40 T – 

0.54 SN 

1.95 T – 

2.09 SP 2 O 5 

1.92 T – 0.39 

SK 2 O 

Jharkhand 

Kharif Red Loam HYV 

6.14 T – 

0.55 SN 

2.83 T – 

2.16 SP 2 O 5 

3.73 T – 0.70 

SK 2 O 

West bengal 

Kalyani 

Kharif - 

IET- 

4094 

3.5-4.0 

3.60 T – 

0.25 SN 

2.29 T – 

.82 SP 

2.61 T – 0.19 

SK 

Kalyani, Rabi - IET- 5.0-5.5 2.75 T – 0.48 T – 1.24 T – 0.62 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217 

Page | 25

4786 0.63 STVN 0.54 STVP - 

0.07M 

STVK -0.24M 

Barrackpore 

Khitish 

7.51 T – 

1.90 T – 

2.63 T – 0.21 

Ratna 

0.37 SN – 

0.33 SP – 

SK – 0.05 OK 

Jaya 

0.23 ON 

0.29 OP 

2.83 T - 0.54 

3.28 T - 

4.80 T - 

SK 

0.18 SN 

5.02 SP 

2.83 T - 0.38 

4.80 T - 

7.74 T - 

SK 

0.54 SN 

11.02 SP 

Haryana 

Hisar 

Sierozem 

(Inceptisol 

s/Entisols) 

PR 106 6.0-7.0 

3.70T – 

1.10 SN 

1.35T- 

2.66SP 

- 

Uttaranchal 

Pantnagar 

PD-4 4.0-5.0 

5.72 x YT 

(q/ha) – 

1.01 SN- 

0.95 FYM- 

N 

0.93 x YT 

(q/ha) – 

0.72 SP- 

0.23 FYM-P 

1.15 x YT 

(q/ha) – 0.20 

SP-0.30 FYM- 

K 

Madhya 

Pradesh 

Bhopal, Dhar, 

Medium 

black and 

- 

4.25 T – 3.55 T – 2.1 T – 0.18 

Page | 26 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Jabalpur, 

Indore, 

Deep black 

soils 

0.45 SN 4.89 SP SK 

Khandwa, 

Narsinghpur, 

Powarkheda, 

Khargone, 

Satna, Sagar, 

Sehore, 

U 

j 

j 

a 

i 

n 

. 

Orissa 

(Bhubneswer 

) 

Lalat 

8.4 T – 1.4 

SN 

5.0 T – 3.1 

SP 

6.6 T – 1.5 SK 

Site specific integrated nutrient management (SSNM): Strategies 

The classical approach for developing fertilizer recommendation is based on empirical response 

functions derived from factorial trials conducted at different locations. A key problem in these is 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217 

Page | 27

that the nutrient interactions at higher yield levels is less understood particularly the relationship 

between plant uptake and the internal nutrient efficiencies. The QUEFTS model (Jannsen et al 

1990; Smaling and Jannsen, 1993) was adopted by IRRI to predict soil nutrient supply and plant 

uptake in absolute terms. The model described in four steps the relationship between soil test 

value, potential NPK supply from soils and fertilizers, actual NPK uptake and grain yield 

acknowledging interaction among major nutrients. It accounted for climatic yield potential and is 

particularly suitable for irrigated rice systems where water stress is not experienced. 

The strategy of SSNM focuses on managing field variation in indigenous supply of soil nutrients, 

temporal variability of plant N status, medium term changes in P and K supply potential of the soil 

based on nutrient balance. The required information is 

 

 

 

 

 

Potential yield and yield goal, 

Relationship between yield and nutrient uptake, 

Recovery efficiencies of fertilizer NPK, 

Field specific estimates of internal supply potential of N,P and K and 

Optimization of the constraints 

Potential yield is estimated based on crop models (ORYZA 1 model) and yield goal of about 75-80% 

of that is fixed. The relationship between yield and nutrient uptake for determining nutrient 

requirement is described as a function of climatic yield and nutrient supply which is linear up to 

75-80% of maximum yield under ideal conditions of balanced nutrition beyond which nutrient 

interactions dominate. In the linear range average requirement of nutrient is 14.7 kg N, 6.0 kg 

P 2 O 5 , and 17.5 kg K 2 O per ton of grain. Recovery efficiency of applied nutrients range from 40-60% 

N, 20-30% P and 40-50% K. Indigenous nutrient supply are estimated based on crop uptake in 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217 

Page | 28

espective nutrient omission plots since soil test values are many times erroneous to assess the 

soil potential. Nutrient level is calculated as follows: 

Nutrient (N) level (target 7.0 tons/ha) = [(7.0 x location specific NR) – N uptake in N omission plot] 

/ N recovery efficiency, where NR is N uptake per ton of grain in kg/ton 

The recommended levels by the model suggests for dynamic N management using LCC colour 

charts to fix N timing while P and K are applied based on long term changes in soil status / supply 

capacity. Nutrient balance model adopted for P and K recommendation is based on the estimation 

of residual nutrient uptake of 10 and 30% of P and K. The success of SSNM strategy largely 

depends on accuracy of estimation of indigenous nutrient supply and nutrient recoveries, and fine 

tuning of N management. Empirical studies suggest yield goal to be 10-20% more than the average 

yield already realized but less than 80% of climatic yield potential (Table 5). 

Table 5 Comparision of SSNM approach and STCR approach 

SSNM approach 

N Management through LCC based on leaf 

colour where optimum time is taken 

P & K management based on missing plot yield of 

previous year of some season 

In wet land rice, normal soil testing results do not 

correlate with nutrient supply/uptake. Hence, 

actual nutrient uptake in nutrient omission plots. 

STCR approach 

Soil test based on optimum time is taken care 

by split doses. 

P & K management based on soil test values 

Plot omission technical is not followed. 

Nutrient uptake by plant in control treatment 

is taken into consideration. 

Fertilizer nutrient required = Total nutrient 

requirement -Soil Nutrient supply 

Based on soil test values, 

contribution from fertilizer plant nutrient 

requirement and desired yield of the 

Page | 29 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

farmers. 

Recommendations are only for rice 

Direct estimation of Nutrient supplying 

capacity of soil for a particular crop and 

location 

Every farmer must conduct omission plot 

experiment during previous year to workout the 

fertilizer recommendation of current year which 

is very difficult. 

SSNM encourages the use of locally 

available nutrient sources 

particularly organic and biological 

sources 

Less N losses as N in more split doses is applied. 

Soil moisture should be sufficient when crop 

based on LCC. Thus, more number of irrigations 

requirement especially in case of wheat. 

Regular monitoring by skilled person is required. 

More split doses increases the cost of N fertilizer 

application 

Technology is available for almost all crops 

including cereals, pulses, oilseeds, some 

vegetable crops tested in farmers’ field and 

demonstrated for 2-3 years also. 

For a crop and location validation of target 

yield equation are required. 

Farmer need not conduct omission plot trial 

during previous year. 

This INM approach involves locally available 

organic and biological sources. 

Almost similar in N losses. 

Less number of irrigation 

Not required for this purpose. 

Cost does not increased 

Page | 30 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Experimental data is based on the on farm trials 

whose authenticity is poor in (-) N plot 

More authenticity compared to SSNM 

IPNS cannot be included in fertilizer 

recommendation 

If there is no good correlation between nutrient 

uptake and crop yield, recommendation is not 

done based on soil test values. 

Efficiency of fertilizer input is taken from previous 

known general values. 

It can be included in 

recommendations 

Recommendations are done based soil test 

values, nutrient uptake and yield targets 

Efficiency for fertilizer is estimated for a 

representative site 

SSNM- Indian experience 

The SSNM approach followed in India basically does not deviate from the IRRI model but has 

integrated both STCR and IRRI approaches. It aims at maximizing farmers’ profits by achieving 

maximum economic yield (MEY). It was introduced in priority areas facing one or more of the 

problems like imbalanced nutrient use with low yields, crops showing nutrient deficiencies in large 

scale, endemic to pests and diseases linked to nutrient management, evidences of P and K mining 

and in areas of multi-nutrient deficiencies particularly of secondary and micronutrients. 

The available knowledge on SSNM was utilized in rice-wheat system at several locations to 

evaluate its application for achieving total system productivity of 15-17 tons/ha (Tiwari et al., 

2006) and in rice-rice cropping systems. The systematic implementation of SSNM involved sound 

agronomic management of the crop combined with need based nutrient application. The results 

were encouraging with highest annual grain yields of > 16t/ha at Modipuram, Ludhiana; 14-16 

t/ha at Kanpur; 12-14 t/ha at Faizabad, Varanasi, Pantnagar, Sabour, R.S.Pura; 10-12 t/ha at Ranchi 

and 8-10 t/ha at Palampur. Averaged over all locations SSNM showed yield advantage of 3.4 t/ha 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217 

Page | 31

or 34% over farmers’ fertilizer practices with benefit cost ratio of 4.9 (additional income > Rs 

15000). In many locations yields of rice were more than 10 t/ha because of hybrids. 

Guidelines for N Management: 

Nitrogen promotes rapid growth and affects all parameters that contribute to yield. Crop N 

status is closely related to rate of photosynthesis and crop production. Sufficient N supply to 

the crop increases the demand for other nutrients such as P, K and other micro and secondary 

nutrients which are required for full expression of yield potential. 

Soils with very low soil organic matter content (e.g.,

Excess N causes lodging, delays maturity, induces spike let sterility and reduces tolerance 

to pests and diseases. 

Depending on the season, duration of variety and site characteristics, split application of N 

(2-4) to match crop N demand at transplanting rice @ 30-50 % of recommended dose, rest 

top dressed at tillering and 3-5 days before panicle initiation in equal proportion is 

recommended. 

Early N application before 14 DAT or 21 DAS of rice depends on yield response, season and 

genotype - At yield responses of 1-3 t/ha apply 20-30 kg N/ha, or 25-30% of total N for >3.0 

t/ha response as early N dose 

Rest of the dose should be top dressed in 2-4 splits based on leaf color chart (LCC). 

Early N application (incorporation) should be increased for low tillering large panicle type 

varieties, for older seedlings of short duration varieties, for wider spaced crop and in areas 

of low temperature at transplanting time. 

Reduce or avoid early N application when high quality organic materials or composts are 

applied or in soils of high N supply capacity (soil OC > 2.0%). 

Real time N management using leaf color chart (LCC), as a guiding tool for proper timing 

substantially improved N efficiency and save fertilizer N to the extent of 15-30% (Table 6) 

In areas of uncontrolled water situations (rain fed) soil placement of N or incorporation of 

urea coated with neem cake or its formulations have been very effective. 

Legumes in the cropping system, supplementation with available organic manures, 

recycling of crop residues and use of bio-fertilizers have proven to be very efficient 

substitutes for N and other nutrients with additional advantage of building soil quality. 

Rice hybrids with higher yield potential respond to higher nutrient application but are also 

reported to be efficient utilizers of nutrients. Additional dose of N at flowering is also 

recommended for hybrids to delay senescence and support large sink filling (Table 7) 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217 

Page | 33

In areas where top dressing of N is not feasible due to stagnant and uncontrolled water 

situations, N can be applied for quick recovery as spray @ 2-4% with knapsack sprayer or 

up to 15-20% when a high pressure low volume sprayers are used 

Substitute 25-50% N through green manures/ FYM/compost/ bio-fertilizers to improve N 

economy and sustain soil and crop productivity. 

Real time N management using LCC 

Leaf color chart (LCC) is used only for top dressing of N 

Read the color of top few leaves at 7-10 days interval from early tillering to booting stage 

Apply fertilizer N @ 50, 75, 100 or 125 kg urea / ha as top dressing, respectively for low, 

medium, high, or very high response environments each time at tillering and 3-5 days before 

panicle initiation stage 

Table 6 Real time management of N in farmers’ fields 

Treatment 

N used 

Grain yield 

AEN (kg N/kg N) 

N saved 

(kg/ha) 

(t/ha) 

kg/ha) 

Cauvery delta 

Control 0 4.94 - - 

Local practice 125 7.26 19 - 

SPAD 35 60 7.62 41 60 

Haryana (2001) 

Farmers practice 144 6.36 - - 

LCC-3 124 6.37 - 20 

Page | 34 





Ph: 91-40-24591218, 295 Fax: 91-40-24591217

Table 7 Relative use efficiency of N by Rice hybrids, kharif 2001 (DRR) 

Genotype 

Yield 

AE (kg 

N uptake 

NHI 

PE (kg 

N 

(t/ha) 

grain/kg 

(kg/ha) 

grain/kg 

requirement 

N) 

Grain 

Total 

Nu) 

(kg N/t grain) 

PHB 71 5.49 14.2 52.6 82.3 0.64 66.7 15.0 

KRH 2 5.39 13.2 52.0 81.7 0.64 66.0 15.2 

HYV 4.11 11.7 39.6 66.5 0.59 61.8 16.2 

LSD (0.05 0.18 1.6 3.6 3.8 0.04 - - 

Phosphorous and Potassium Management of P and K aims to sustain the nutrient supply at levels 

that do not limit crop growth, ensure optimal N use efficiency and increase plant resistance to 

pests and lodging. These nutrients are to be supplied to overcome nutrient limitations, replenish 

crop P and K uptake and avoid excessive use when not required. Important components of P and K 

management are soil supply potential, timing and placement depending on soil type, tillage, crop 

establishment and plant population, and long term changes in soil reserves. 

Phosphorous (P) management: 

The second most important plant nutrient, P is required for better root and shoot growth, 

starch mobilization and as source of energy. 

P is mobile within the plant and promotes tillering, root development, early flowering, and 

ripening. It is particularly important in early growth stages. Hence all recommended P 

should be applied as basal dose. 

Phosphorous is less available in coarse-textured soils containing small amounts of organic 

matter and small P reserves. Calcareous and saline soils, and acid laterites and acid-sulfate 

soils (strongly P-fixing) 





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P deficiency reduces growth of roots and shoots; affected plants have few tillers with 

small, erect and dark green leaves with purple tint. 

Rice requires 5-9 kg P 2 O 5 / ton of grain and recovers about 15-25% of applied P with 

substantial residual effects. 

Depending on site characteristics, for a 6.0 t target yield/ha about 50 kg P 2 O 5 /ha fertilizer 

is required at native soil productivity of 4.0 t/ha, 6 kg P 2 O 5 /ton requirement and 25% 

recovery efficiency (Table 8). 

Table 8 Guidelines for P 2 O 5 recommendation for non – fixing soils 

Yield target (t/ha) 4 5 6 7 8 

Yield in P0 plot 

(t/ha) 

Fertilizer P 2 O 5 rate (kg/ha) 

3 20 40 60 - - 

4 15 25 40 60 - 

5 - 20 30 40 60 

6 - - 25 35 45 

7 - - - 30 40 

8 - - - - 35 

Apply higher P dose in cold/ rabi seasons and for legumes/ oil seed crops in rotation 

Being less mobile in soils and prone to fixation in calcareous and acid soils, the 

management of P needs careful consideration of total requirement of the cropping system, 

temperature regimes, and overall productivity 





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In acid soils of < 6.0 pH use low cost phosphate rock or its mixture with SSP to economize P 

input cost. 

Supplementing with organics, dipping of rice seedlings in super phosphate soil slurry and 

use of phosphorous solubilising micro-organisms etc substantially insulate P against soil 

fixation, and improve P use efficiency. 

Organic manures (up to 20-30 % of P dose) along with P fertilizer prevents P fixation in 

calcareous, clay and acid soils 

Cultivate P efficient rice genotypes like Rasi, Vikas, IR 64 which are high yielding, early to 

mid early duration group,, and suitable for rabi season. 

Integration of deep rooted crops like chick pea with upland rice in the cropping sequence 

and / or application of P to pre kharif green manure / grain legume crops in lowlands 

mobilize P and prevent from soil fixation (Table 9). 

Table 9 Rice yields and soil available N and P in rice –chick pea rotation, DRR 

Treatment 

Rice yield 

Soil 

Soil available P 

(t/ha) 

available N 

(kg /ha) 

(kg/ha) 

Control 775 163 7.6 

Chick pea 1543 192 13.4 

Chick pea+ 

P40 

2226 202 16.6 

Potassium (K): 

Potassium increases spike let fertility and root oxidizing power, influences translocation of 

sugars to the grain besides improving plants tolerance to pests and diseases. 





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Indian soils though show medium to high K fertility, the outflow of K by crops and cropping 

systems is very high (at 20-25 kg K 2 0/ton grain). 

At the current levels overall balance of K in the system is negative in majority of the crop 

systems needing K application in quantities sufficient to prevent depletion of the nutrient 

to acute levels. 

For a target yield of 6 t/ha with 4.5 t/ha average yield at native soil fertility about 65-70 kg 

K 2 O/ha is required (Table 10-12). 

Recommended sources of K are MOP (50%) and paddy straw (50%) 

Half of the recommended K should be applied as basal and remaining half at panicle 

initiation stage especially for hybrid rice. 

Table 10 Guidelines for K 2 0 recommendation for low straw recycling 



(t/ha) 

Fertilizer K 2 0 rate (kg/ha) 

3 45 75 105 - - 

4 30 60 90 120 - 

5 - 45 75 105 135 

6 - - 60 90 120 

7 - - - 75 105 

8 - - - - 90 

Table 11 Guidelines for K 2 0 recommendation for medium (2-3 t/ha) straw recycling 





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(t/ha) 


3 30 60 90 - - 

4 0 35 65 95 - 

5 - 20 50 80 110 

6 - - 35 65 95 

7 - - - 50 80 

8 - - - - 65 

Table 12 Guidelines for K 2 0 recommendation for high (5t/ha) straw recycling 



(t/ha) 


3 30 60 90 - - 

4 - 30 60 90 - 

5 - - 30 60 90 

6 - - 10 35 70 

7 - - - 25 55 

8 - - - - 40 

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Recycling of crop residues rich in K, split application in high productivity systems (eg. 

Hybrids) (Table 13), additional dose of K in acid soil environments prone to iron, Al, sulfide 

toxicity etc all benefit the crop system and support high crop production. 

Table 13 Response (t/ha) of rice hybrids to potassium (DRR) 

Location Genotype Method of K application 

control Basal Split (2) 

Chinsurah (30 

kg/ha) 

Hybrids 3.61 4.12 4.40 

HYVs 3.22 3.65 3.83 

Faizabad (60 kg/ha) Hybrids 5.18 5.43 5.61 

HYVs 3.88 4.11 4.31 

Moncompu (35 

kg/ha) 

Hybrids 5.07 5.85 6.33 

HYVs 3.61 4.72 4.90 

Titabar (40 kg/ha) Hybrids 2.92 4.32 5.21 

HYVs 2.70 4.04 4.34 

The concept of SSNM was applied to refine further the current fertilizer recommendations 

for rainfed shallow low land rice in the states of Assam and UP by directly collecting the relevant 

data by conducting trials in the farmers fields and verification of the revised dosages (Table 14). 





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Similarly it was also attempted at DRR and farmers fields in the surrounding district. There was a 

large deviation from the current practices in the fertilizer prescriptions particularly in the lowland 

systems and showing large farm variations in soil nutrient supply, yield levels and use efficiency. 

Recommendations based on SSNM principles when evaluated improved rice yields and was 

sustainable. Validation of SSNM (estimated in kharif 2007) in 5-6 farm sites showed improved rice 

productivity by 5-17% depending on the location over currently recommended and farmers’ 

fertilizer practices suggesting its importance in sustaining crop yields and soil fertility and the need 

for refinement of fertilizer recommendations (Table 15a & b). Similarly this concept was applied in 

Cauvery delta, Tamil Nadu which further refined the fertilizer recommendations. The results were 

encouraging in terms of improved nutrient use efficiency and productivity of rice systems and 

were convincing (Tables 16 and 17). 

SSNM for sustaining productivity of intensive rice crop system (R-R) in RR district included – 

Average nutrient supply potential of the soil ranged from 49-54 kg N/ha, 31-33 kg P2O5/ha 

and 45 -66 kg K2O/ha 

Soil nutrient supply and agronomic efficiency varied with varieties and seasons - it was 

higher in rabi 

Nutrient requirement at estimated maximum yield of 6.2 and 7.0 t/ha in wet and dry 

seasons ranged from 19 – 20 kg N, 10-11 kg P2O5 and 13-15 kg K2O per ton grain. 

Internal efficiency (yield Vs uptake) in the linear range was 58, 354 and 115 kg grain/kg of 

N, P or K uptake. 

INM (GM and FYM) in kharif improved rice productivity and N use efficiency 





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Table 15a Site specific fertilizer recommendation (kg/ha) for a target yield in 

kharif (DRR, 2007) 

Nutrient 

Titabar 

Mandya 

Ghaghraghat 

(12 sites; 5.0 

(10 sites; 6.7 

(20 sites; 7.0t/ha) 

t/ha) 

t/ha) 

Range Range Range 

Nitrogen 46-79 103-169 123-197 

Phosphorus 30-42 47-70 58-95 

Potassium 42-64 91-132 34-108 

RDF: 40-20-20 100-50-50 120-60-50 

NR (kg/ha): 13.2-3.2-13.3 15.3-5.9-20.6 - 

Table 14 Validation of SSNM recommendations in farmers’ fields, kharif 2008 

Parameter SSNM STCR Current RDF CD (0.05) 

Titabar (Target 5.3 ton/ha) 

Grain Yield 

(t/ha) 

5.84 5.13 5.00 0.39 

Ghagraghat (Target 6.7-7.0 t/ha) 

Grain Yield 

(t/ha) 

6.79 6.49 5.79 0.19 

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Nutrient Uptake (kg/ha) 

N 161.0 150.0 135.0 6.0 

P2O5 44.3 40.9 36.8 1.6 

K2O 281.5 258.7 229.7 14.4 

Table 16 Influence of SSNM on grain yield and nutrient use efficiency in Tamil Nadu 

Location/ 

Yield 

AEN 

RE (%) 

Average Fertilizer 

Treatment 

(t/ha) 

(kg grain / kg N) 

(NPK) use (kg/ha) 

Aduthurai 

SSNM 6.0 – 7.0 14.3 – 17.4 39 – 43 127 : 26 : 70 

FFP 5.5 – 6.5 12.3 – 15.2 35 – 43 112 : 24 : 38 

Thanjavur 

SSNM 5.0 – 6.2 14.0 – 15.3 43 – 48 129 : 19 : 80 

FFP 4.3 – 5.6 11.5 – 15.3 40.51 96 : 17 : 36 

Nagarajan et al., 2004 

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Table 15b--- Evaluation of SSNM in on-farm trials (kharif 2006) 

Yield SSNM* FFP 

Grain yield (t/ha) 5.3-8.4 (7.0) 4.9-7.1 (6.4) 

Straw yield (t/ha) 5.1-7.9 (6.5) 4.0-8.4 (6.0) 

Yield increase(%) 3.0-27.0 - 

N uptake (kg/ha) 100-150 (124) 79-125 (115) 

P2O5 uptake (kg/ha) 60-110 (83) 56-84 (69) 

K2O uptake (kg/ha) 104-176 (135) 86-160 (125) 

Internal efficiency (kg grain 

N 51-61 50-63 

P2O5 69-108 80-112 

K2O 43-67 44-58 

Nutrient requirement –18 kg N, 6kg P2O5,, 15 kg K2O / ton of grain 

efficiency –48%, 25%, 45% Yield target-7.5 t/ha, Varieties: BPT 5204, 

Surekha, Manish, 

*Data from 7 sites. 

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Table 17 Rice yield under GIS map based (Precision) fertilizer recommendation 

Season Farmers’ practice GIS based 

recommendation 

Kharif 3.1-3.6 2.7-4.2 

Boro rice 5.5-6.0 6.8-7.2 

(Sen et al., 2008) 

Achieving sustainable productivity growth requires an ideal balance of nutrients in the crop as 

suggested by Janssen (1998) that maximize utilization efficiency of nutrients which is presented in 

the Table--- . 

Table --- Range of nutrient utilization efficiency (NUE) observed in cereal crops 

NUE (kg grain/kg nutrient uptake) 

Nutrient 

Minimum Maximum NUE index (%) 

N 30 70 50 

P 200 600 50 

K 30 70 50 

Average 50 

NUE index (for N) = (NUE -30)/ (70-30) X 100 (Ref: Janssen (1998) 





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Secondary and micronutrients - The strategy involves diagnosis and application of deficient 

nutrients. More important in the management of these nutrients is whether to apply, if so how to 

apply and the timing rather than how much to apply. 

Zinc (Zn): The micronutrient (Zn) is widely deficient in Indian rice soils (> 8.0 million ha) and is 

required in initial stages of rice growth for developing aerenehyma tissue, biosynthesis of auxins, 

protein synthesis and gene expression. Soil application in acutely deficient and high pH soils (@ 

30-50 kg/ha) and/or mid season correction by spraying ZnSO 4 or chelated zinc (0.50%) are 

recommended. It is preferred to apply Zn in cooler, high productivity seasons for rice and to crops 

which need more zinc in cropping system to effectively utilize the residual nutrient. 

Sulphur (S): Being a constituent of important amino acids such as cysteine, cystine, methionine 

and proteins, and generally required in larger quantum for oil seed crops, the outflow of S even by 

cereal crops like rice is also high (3-5 kg/ton grain). This suggests for efficient S management 

considering the total S removal by a cropping system particularly in high rainfall rain fed lowland 

rice systems where reports of S depletion and response to S application have been reported. Nonuse 

of S fertilizers and increasing cropping intensity are also contributing to the emerging 

problems of S nutrition. S sources like gypsum, phosphogypsum, ammonium sulphate, elemental 

S, and organic manures / crop residues as a part of INM are recommended to supply about 30kg 

S/ha per crop as efficiency of S are relatively low 

Coupled with these is the need to alleviate soil problems and related secondary 

nutrient constraints for sustaining crop productivity. Promoting, therefore, site-specific integrated 

nutrient management (SSNM) depending on the resources available and keeping in view crop 

nutrient demand, productivity targets of the component crops in a system soil nutrient supply and 

nutrient flows while alleviating in situ soil problems in very much essential for improving and 

sustaining soil and crop productivity and to support future gains. 





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Integrated Plant Nutrient Management System: (IPNMS) 

Concept: Integrated plant nutrient management involves monitoring all pathways of plant 

nutrient supply in crops and cropping systems and calls for a judicious combination of fertilizers, 

bio fertilizers and organic manures. The basic concept underlying IPNS is the maintenance of soil 

fertility, sustainable agricultural productivity and improving profitability through judicious and 

efficient use of fertilizers, organic manures, crop residues, bio fertilizers, suitable agrochemical 

practices, conservation agricultural practices and nutrient efficient genotypes. Soil testing and 

assessment of productivity potential and targets for crops and cropping system, estimation of 

nutrient requirements, soil nutrient supply potential and fertilizer use efficiency besides 

assessment of resource base and socioeconomic background of the farmers are essential for 

suggesting and practicing site specific IPNS. The system also involves monitoring all the pathways 

of nutrient flows in the cropping system from all the sources to maximize the profits. 

The IPNS system demands a holistic approach to nutrient management. IPNS is not new to Indian 

agriculture and a lot has been written on the subject. There have been several causes apart from 

weak extension that has contributed to declining use of organic sources - 1) Excellent responses 

to fertilizer use, its easy availability and handling until appearance of secondary and micronutrient 

deficiencies 2) Cumbersome procedures and drudgery in making manures/composts and their 

usage, and 3) less economical compared to the fertilizers in view of their low nutrient contents, 

application in bulk quantities, slow release of nutrients to the crops, lack of quality norms and 

most important the need for faster dissemination of green revolution technologies to enhance 

food production. While the organic nutrient sources are definitely of low nutrient concentration 

material which is available to plant uptake only upon microbial decomposition and nutrient 

release, the material were rich in all plant nutrients and organic carbon that provide stability to 

the quality of the system. 

The importance of organic sources could only be realized when the 

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productivity growth stagnated and yields started declining requiring increasing levels of nutrient 

application which led to depletion of plant essential nutrients from the soil system. 

Components of IPNMS and their use: Major components of integrated nutrient management are 

 

 

 

 

 

 

Integration of soil fertility restoring crops like green manures, legumes etc. 

Recycling of crop residues 

Use of organic manures like FYM, compost, vermicompost, biogas, slurry, poultry manure, 

Bio compost, Press mud cakes, Phosphocompost 

Utilisation of Bio fertilizers 

Efficient genotypes and lastly 

Balanced use of fertilizer nutrients as per the requirement and target yields. 

Organic nutrient sources. 

Organic sources of plant nutrients include growing of legumes in the cropping system, green 

manures, crop residues, organic manures (FYM, compost, vermicompost, biogas slurry, 

phosphocompost, biocompost, presmud, oil cakes etc) and bio fertilizers. Available information 

show that organic manures in addition to fertilizers sustain high crop yields over long periods as 

compared to application of only fertilizers as observed in many long term studies (DRR, 2007; 

2008; Rajendra Prasad 2008). The results indicate scope for substituting more than 25% of 

recommended dose of NPK with organic sources in intensive cropping systems. Under ideal 

conditions green manures and grain legumes when integrated into the cropping system has the 

potential to meet more than 50% of N requirement of the immediate rice crop. Further addition of 

organic manures as part substitutes or supplementary (add on) improved soil physic-chemical and 

biological properties and ultimately its quality. Biofertilizers (N fixing, P solubilising, cellulolytic 

microorganisms) facilitate economizing fertilizer nutrient use through utilizing BNF systems, 





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solubilising less mobile nutrients from fixed components and recycling of nutrients from crop 

residues. Integration of such systems makes the production system more stable and sustainable. 

Legumes and green manures: Grain and fodder legumes and green manures can fix atmospheric 

N to the extent of 50-500 kg N/ha before the plant starts flowering (about 40-60 days growth) 

except by soybean. The residues of legumes after harvest of grain contain 25-100 kg N/ha which is 

released at a steady rate when incorporated because of optimum lignin content. Green manures 

accumulate 100-200 kg N/ha in about 50 days period of which 60-80 per cent is fixed from 

atmosphere (Rao et al., 1996) and can meet 60-120 kg/ha of N requirement of rice (Tables18-19). 

Besides N, the crop mobilizes less available soil P and K which can be recycled into the system. A 

60 day green manure was reported to accumulate 20 kg P 2 0 5 and 125 kg K 2 0/ha in their biomass 

which gets released upon decomposition and is less prone to soil fixation because of organic 

environment. The deep rooted grain legumes also have the potential to recycle sub soil nutrients 

to the benefit of the following cereal crops in the cropping system. 

Green manures (GM) under many situations can meet entire N demand of a crop more efficiently 

than fertilizer urea (Rao and Shinde, 1991) (Table 20). The GM crops had C:N ratio of 14-15 at 30 

days and 18-19 at 60 days, and mineralize in 15 days 41-43% of biomass N of a 30 day old crop 

while a 45 day old GM crop took 30 days to mineralize same amount of biomass N. A 60 day old 

GM crop when incorporated released 20-30% of biomass N after 15 days and 26-30% in 30 days. 

The biomass N release rates depend on plant characteristics like lignin content, C/N ratio, N 

content, age of the residue, etc. 

Multilocation trials in rice-wheat and rice-rice system indicated that GM crops can on an average 

supply 50% N requirement of rice, with considerable impacts on soil organic C, and N and K status 

of soils besides improving soil physical conditions. There is, however, a discouraging scenario of 

green manuring. Its area has decreased because of lack of space and time under conditions of 





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increasing cropping intensity, non-availability of seed, and availability of fertilizers at subsidized 

rates. Integration of grain or fodder legumes, as alternatives, has been equally effective as any 

GM crop in terms of N supply with an additional income on the legume grain harvested. 

Table 18 Estimate of biological N fixation by green manures and dual purpose grain legumes in 

kharif season (DRR) 

BNF (kg N /ha)** 

Test Crop 

Total Dry matter 

N accumulation 

Difference 

Regression 

(t/ha) 

( kg / ha) 

method 

method 

Daincha 10.2 281 246(88) 255(91) 

S . Rostrata 8.3 244 209(80) 218(89) 

Sun hemp 7.5 222 187(84) 196(88) 

Cowpea 5.2 164 129(79) 137(84) 

Cluster bean 8.5 211 176(83) 184(87) 

Green gram 4.1 96 61(64) 68(71) 

** Estimated with reference to jowar as non-fixing crop; figures in parenthesis are in 

percentage 

(Rao et al ., 1996) 

Table 19 Rice yield response and urea N equivalents applied through green manures (WS) (DRR) 

N Soure 

N 

Grain 

N use 

Urea N 

applied 

Yield 

efficienc 

Equivalents 

(Kg / ha) 

(t/ha) 

y (AE) 

(Kg/ha) 

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Daincha 172 4.70 12.6 99 

S. Rostrata 182 4.81 12.5 105 

Sunnemp 148 4.51 13.4 88 

Cow pea 76 3.90 18.1 53 

Cluster bean 64 4.50 31.0 87 

Green gram 37 3.55 27.9 33 

Glyricidia . Sp. 145 4.82 15.9 105 

Control (No) - 2.53 - - 

Urea 80 80 4.46 24.2 - 

Urea 120 120 5.43 24.2 - 

Urea 160 160 5.36 17.7 - 

C D - 0.79 - - 

(Rao et al ., 1996) 

Table 20 N balance of green manure and urea 

Source 

Yield ( t / 

Plant 

Soil Loss Residual 

Total 

(80 Kg N 

ha) 

uptake 

uptake 

Loss 

/ha) 

No 3.3 - - - - - 





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Daincha 5.3 26.8 31.2 32.0 3.4 24.1 

Sun hemp 5.0 17.0 17.0 23.0 2.3 32.5 

Urea 5.1 19.1 19.1 28.0 1.3 39.0 

LSD (0.05) 0.3 - - - - - 

(Rao and Sinde, 1991) 

Crop residues: Mechanisation of Indian farms, semi-urbanisation of villages, increasing cropping 

intensity with low turn around time, decreasing availability of farm labour have led to problems of 

crop residue disposal, which has vast potential to meet nutrient requirement of major ricecropping 

systems. The problem is more intense in the utilization of kharif rice-straw which has 

higher moisture and is generally soiled besides being hardy as a source of nutrients for use in 

intensive crop systems, while that of dry season crops like wheat are utilized as fodder for the 

animals and partially recycled. A ton of rice residue contains 6.0, 2 and 11 kg NPK and wheat 

straw has 5, 0.7 and 10 kg NPK/ t. More than 340 M.tons of crop residues from various crops are 

produced annually of which major quantity is contributed from rice and wheat (nearly 240 M.tons) 

(Table 21). This accounts for nearly 6 million tons of major nutrients of which at least one third is 

tappable for recycling. About 12-16 M.t of crop residues / straw is burnt annually to clear the land 

for early wheat sowing leading to considerable loss of straw N, P, K and S to the extent of 100, 20, 

20, and 80 percent, respectively. In addition to causing environmental pollution, burning results in 

large losses of organic carbon besides plant nutrients. Future increases in food production are 

possible through improved soil productivity. Proper management and utilization of crop residues 

and other agricultural wastes will constitute an important factor in achieving this objective. With 

widespread use of combines, crop residues largely remain in the field and must be managed for 

sustainability of the system. Studies conducted at DRR and elsewhere in R-W region indicate early 

release of P and K upon soil incorporation, while N is released into the soil after a brief period of 

immobilization up to 4-5 weeks. Spreading of chopped rice straw after combine harvest of rice 





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and a booster dose of 20-30 Kg N/ha after rice straw incorporation/spreading hasten its 

decomposition and release of nutrients. Combined use of rice straw and green manure (GM) 

improve and sustain yields compared to standard fertilizer package through increased nutrient 

supply, improved soil physical conditions and favorable biological activity (Tables 22). 

Inoculation of rice and wheat residues with cellulolytic fungal cultures observed improved 

K uptake significantly by 18% (Rajendra Prasad, 2008). Incorporation of crop residues in R-W and 

rice – rice system improved soil organic C, N, and soil physical properties (Surekha et al, 2008) 

besides leaving a positive K balance in the system (Table 23). While the research outcome on 

utilization of crop residues has been encouraging, hastening degradation of crop residues through 

chemical/microbiological manipulations and integration of legume residues or by composting 

needs further studies for effective utilization of such potential nutrient sources. 

Table 21Potential availability of organic manures, crop residues and nutrients 

during 2000-2025 

Manures 2000 2010 2025 

P T P T P T 

Animal manures 392 126 415 134 448 145 

Nutrients 8.6 3.6 9.2 3.9 10.1 4.4 

Crop residues 300 99 343 112 496 162 

Nutrients 

(N+P205+K20) 

6.2 2.1 7.1 2.3 20.3 3.4 

P- Potential; T-Tappable 

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Table 22 Influence of crop residues on partial N balance crop rice - rice system 

(1996-1999) ( kg N /ha) 

Total N applied 

Total N uptake 

Cumulative N 

Treatment 

(kg/ha) 

(kg/ha) 

Balance/season (kg/ha) 

G M 639 – 1067 556 – 677 (+) 83 – 390 (+) 14 – 65 

G M + Str 655 – 1083 482 – 627 (+) 173 – 456 (+) 29 – 76 

Rice Str. 373 – 801 502 – 602 (+)129- (+)199 (+) 22 – 33 

Fallow 292 - 660 477 - 590 (+) 70 – (-) 

185 

(+) 12 – (-) 31 

(DRR, 2000) 

Table 23 Rice residue management on nutrient balance and soil quality in RR system 

Treatment Yield (t/ha) Apparent Nutrient 

balance 

Soil Quality 

R K N K BD 

(g/cc) 

OC 

(%) 

Resp 

(mg co2 

/g) 

RS (I) 7.3 3.7 +200 +115 1.25 1.22 0.16 

RS + GM (I) 7.4 4.0 +400 +219 1.21 1.27 0.17 

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RS ( B) 7.5 3.5 +180 _89 1.42 1.16 0.12 

RS (R) 6.3 3.2 +160 (-)107 1.41 1.00 0.11 

CD (0.05) 0.6 0.3 - - 0.10 0.10 0.01 

Initial - - - - 1.42 0.89 - 

Ref: Surekha et al (2008) 

Organic manures: Organic manures vary in their nutrient content, quality and utility as a source of 

nutrients. When properly managed these have high potential as nutrient sources supplementing 

at least 25-35 per cent of nutrient requirement. In Rice – Wheat system FYM @ 15.3 t/ha applied 

to rice was nearly 90 per cent as efficient as 150:60:60 kg N, P 2 0 5 and K 2 0 while in wheat (applied 

@ 20-40 t/ha) FYM was only 35-45% efficient because of low temperatures. As the only source, 

FYM was less efficient while as a supplementary dose along with fertilizer NPK the results have 

been highly encouraging (DRR, 2007; 2008). As a substitute, 50% N requirement of rice and wheat 

could be substituted with FYM and green manures in equal proportions. Long-term studies by 

DRR indicated significant improvement in organic C with FYM (DRR 2007) and also in many other 

such studies. The increase ranged from 4-49% (Swarup, 2002). The manure also influenced soil 

nutrient status positively and many physical and biological properties. 

Vermicomposts contain 1.9% N, 2.0% P and 0.8% K and are comparatively superior to FYM in their 

effects on crop productivity as reported in studies with rice perhaps due to higher N and P 

contents and manure characteristics. The impacts of vermicompost on soil quality were also 

superior to FYM in many cropping systems. 

Poultry manure (PM) is generally richer in P (1.8% N, 2.5% P and 1.4% K) and other nutrients 

which makes it a good source. In a laboratory study 45% of PM-N mineralized in 4 weeks as 

compared to only 12% from FYM-N, while as N source to rice 4 t PM and 60 kg N/ha was 

equivalent to 120 kg N/ha as urea. Similar effects were also recorded at DRR. 





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Biogas slurry (BGS) contains about 1.4, 1.2 and 1.0% NPK and was as effective as urea for rice and 

wheat in a study conducted at IARI in light textured soils. It is more efficient source of nutrients 

than strait fertilizers alone when > 50% N requirement is substituted with BGS (Gupta et al 2002). 

Biocompost (BC) It is prepared by mixing press mud cake (PMC) with spent wash from distilleries, 

and contains 1.9, 1.85 and 1.5% NPK besides many micronutrients. It was reported to be a good 

source more efficient than fertilizers when applied @ 5 t/ha BC + 50% RDF for wheat. The 

material also influenced soil quality (nutrient supply, OC) and recorded 22% more wheat yield 

(Tripathi et al 2007). 

Press mud cake (PMC) is a waste product of sugar industry, and about 9.0 M.t. is produced 

annually. It contains about 1.6, 1.0 and 0.8% NPK. Applied @ 5.0 t/ha along with 40-60 kg N/ha to 

rice, PMC was equally effective as 120 kg N/ha as urea with significant residual effects on wheat to 

the extent of 40 kg N and 13 kg P/ha (Yadvinder singh et al 2003). The material also improved soil 

OC by 50%, total N by 60% and the biological properties by 91 % (SMBN). 

Phosphocompost (PC or PEC): Enriched with P (SSP or RP) phosphocompost can be a good organic 

source of nutrients particularly of P in phosphorous fixing soils. 





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Following NADEP method of 

composting Dhawan et al (1996) reported increased P content from 0.69 to 0.92 and 0.98% when 

enriched with RP and SSP, the latter also improving N content by preventing loss of N through 

ammonia volatilization during composting. Combining PSB inoculation with phospocomposting 

with RP, the citrate soluble P of the fertilizer also improved, which make it useful even in 

calcareous soils. 

Biofertilizers : Biofertilizers are cultures of micro organisms that are capable of fixing atmospheric 

N, solubilising less soluble P forms, mobilizing native soil P and K and for accelerating 

decomposition of organic material while composting or directly used in the fields to decompose 

crop residues. 

N fixers are symbiotic (Rhizobium sp.,) and non symbiotic (Azotobacter; 

Azospirillum; blue green algae, Azolla etc.). 

Rhizobium cultures are used for the legumes, the 

residues of which can be recycled into the cereal crop system, while Azospirillum, BGA and Azolla 

are directly used in the rice fields. Estimates of N fixation in rice fields range from 25-30 kg N/ha 

Page | 56

y BGA and was reported to increase rice yield by 14%’ BGA inoculation with 50% N as NCU was 

reported to be equivalent to 120 kg N/ha as urea. 

Azolla (fern) has been used as N fixer in rice in china since 6 th century. An algae Anabaena 

sps. associated with it fix atmospheric N. The fern prefers low temperatures (16-17 0 C) but many 

cultures were identified that survive at 30 o c. Under field conditions it can fix 30-40 kg N/ha but 

requires 15-20 kg P205/ha to fix N. Azolla is grown simultaneously with rice as a dual crop but it is 

more useful as a source of N when used as a green manure. 

depends on the growth rate and doubling time. 

The quantum of N incorporated 

Phosphate solubilizing organisms (PSO - PSB, PSF): The organic acids (gluconic, lactic, citric, 

tartaric) released by PSO decompose rock phosphates and release P thereby improving its 

efficiency as a nutrient source, and is reported to increase rice yield. Sharma and Prasad (2003) 

reported comparable efficiency of RP + PSO and DAP, which improved further with the 

supplementation of crop residues. PSOs along with RP are effective for pulses though the yield 

improvement is comparatively high in the presence of soluble P inoculated with PSO. 

Nutrient efficient genotypes: Genotypes differ in their response to applied nutrients, utilization 

efficiency and nutrient requirement. Exploiting this variability to identify and utilize in specific 

environments would economise costs on nutrient use and conserve resources. Some of the rice 

varieties like Rasi, Vikas, RPA 5929, few rice hybrids, etc are reported to be efficient utilizers of 

nutrients (Table 24). 

An economic analysis of IPNS and its impact on soil quality changes was done by Singh (2005) 

in a study conducted in Assam. The results in IPNS indicated a net gain in productivity index in 

IPNS and soil quality increased by 5 – 12.5 units in rice based cropping systems when compared 

with farmer’s practice. 





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Table 24 Efficient rice genotypes for nutrient stress situations 

Stress 

Low N 

Low P 

Low Zn 

Fe toxicity 

Genotypes 

Swarna, Sarjoo-52, Bejhary, Pranava, Salivahana 

Rasi, RPA 5929, MTU 2400, Vikramarya 

CSR 10, Sarjoo-52, Vikas, IR-30864 

Mahsuri, Phalguna, Dhanrasi 

An economic analysis of IPNS and its impact on soil quality changes was done by Singh 

(2005) in a study conducted in Assam. The results in IPNS indicated a net gain in productivity 

index in IPNS and soil quality increased by 5 – 12.5 units in two rice based cropping systems when 

compared with farmer’s practice. 

Promoting, therefore, site-specific integrated nutrient management (SSNM) depending on 

the resources available and keeping in view crop nutrient demand, productivity targets of the 

component crops in a system, soil nutrient supply and nutrient flows while alleviating in situ soil 

problems is very much essential for improving and sustaining soil and crop productivity. 

Correction of soil and nutrient related problems 

Coupled with nutrient management is the need to alleviate soil problems and related 

secondary nutrient constraints for sustaining crop productivity because of wide adaptability of rice 

to diverse soil types and conditions including problem soils (for its tolerance and beneficial effects 

during soil amelioration). The drop encounters a variety of field problems which is further 

aggravated by improper and inefficient management of resources and inputs. Important soil and 

management related problems encountered in rice production in India are 

Major soil and management related constraints observed in rice 

Increasing area under soil salinization (8-10 M ha) (salt affected) due to improper irrigation 

and drainage facilities - major portion is cropped to rice 

About 15 M. ha of rice soils are acidic associated with toxicity of Fe, Al, H 2 S, Mn, As, deficiency 

of K, Ca, Mg, B, Si, and P fixation, 





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About 8.0 M. ha of rice area is deficient in zinc (Zn) 

About 3.0 M ha in north-western states under rice-wheat cropping system affected by Mn 

deficiency 

Nutrient problems of deficiency of N, P, K, Zn, Fe, S, Ca, B, and toxicity of Fe, Al, H 2 S, B, Mn, As, 

Salt affected soils 

Electrical conductivity (EC), pH, exchangeable sodium percentage (ESP) and / or sodium adsorption 

ratio (SAR) of saturation extract of the soil besides other soil and water quality-related parameters 

are important characteristics used for classifying the soil problem and for soil management. For 

the soils in Indo Gangetic Plains (IGP) pH 8.2 in place of pH 8.5 was found more appropriate for 

designating sodic soils. Many soils with pH 8.2-10.0 were associated with ESP 15-40, and for pH> 

10 with ESP values of 40-100. Likewise, ECe 2-4 dS/m and ESP 6-15% are used as critical values for 

saline and sodic soils depending on sensitivity of the crops. Several workers also use SAR values to 

calculate ESP since a good correlation exists between these two parameters. 

Table 25 Classification salt-affected soils 

Class US Salinity laboratory Soil Soc. Soc. of America 

Normal ECe 4.0dS/m, ESP >15, pH var. ECe 13 

SAR of saturation extract 

Saline soils: These soils are recognized by the presence of white crusts of neutral salts on the 

surface, non-uniform crop stand (patchy), deep green, stunted plants, and in some sensitive crops 

visible signs of salt injury such as tip burn of leaves and chlorosis. Chlorides and sulfates of sodium, 

calcium and magnesium are the major salts of which sodium constitutes more than 50% of soluble 

cations. The soils have good permeability because of neutral salts. 





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The effects of salinity on rice are osmotic (water stress), toxic ion effects of excess Na and Cl, 

reduction in uptake of K and Ca due to antagonistic influence of Na. Rice tolerates salinity during 

germination, tillering and elongation period, but is very sensitive during early growth (1-2 leaf 

stage) and flowering stages. Salinity symptoms are white leaf tip, stunted and patchy growth in 

the field, reduced germination rate, plant height and tillering, poor root growth, and increased 

spike let sterility. Approximate yield decrease of a susceptible variety due to salinity range from 

10-15% at EC 4-6 dS/m; 20-50% at EC 6-10 dS/m; and > 50% beyond 10 dS /m. 

Management of saline soils: Nature and intensity of soil salinity vary with the soil texture, 

mineralogy, calcareousness, topography, hydrological and drainage conditions. Reclamation and 

management of such soils are location- specific and should include combination of measures. 

Leaching and drainage are two essential components for a permanent solution to salinity 

problem in the root zone (0-20 cm) 

The required quantity of water increases with finer soil texture increased initial soil 

moisture content, degree of salinization, increasing proportion of chlorides, poorer quality 

of water, shallower ground water. Leaching efficiency depends upon depth of applied 

water, soil profile characteristics, ground water table and CEC.. 

Approximately one unit-depth of water of EC

Improving crop survival and better population density by transplanting aged (35-40 days) 

seedlings with more number of plants per hill at closer spacing reduces salinity intensity by 

shading. 

Controlled & frequent irrigation with limited water enhances leaching efficiency, l 

In view of higher N loss, and competitive reduction of P, K and Zn uptake due to Na and Cl 

ions apply about 20-30 per cent more than the recommended levels as per the crop 

demand 

Planting seed on sloping side of the bed, or at the bottom of the furrows prevents salinity 

stress. 

Cultivation of blue-green algae decreased the soil salinity, while VAM was observed to 

improve uptake of P, S and micronutrients by crop. 

Grow saline tolerant high yielding varieties such as CSR 10, CSR 13, CSR 27, CSR 30, Sarjoo 

52, Vikas, 

In coastal saline soils,because of fluctuating salinity (dependant on rainfall), proper crop 

calendar, rainwater harvesting, construction of dykes, provision of deeper drains up to 2.0 

m at 50-100m distance, organic manuring, 25% higher N use, top dressing or spraying of K 

and growing of tolerant rice varieties like Panvel 1, 2 & 3, CSR 6, 10,13, 23, Rasmi, IET 

11353, Lunisree, Vytilla 2, 3, Sumathi improve crop productivity. 

Alkaline or sodic soils: In the presence of sodium carbonate in soil solution, soluble Ca and Mg get 

precipitated; the soils get highly deflocculated resulting in low hydraulic conductivity. Poor plant 

growth due to deficiency of Ca, toxicity of carbonate and high pH. Sodic soils are formed due to 

use of carbonate and bicarbonate containing ground waters. During the wet season, water 

accumulates in low-lying areas and in the dry season soil solution gets concentrated, increases SAR 

of water resulting in high exchangeable sodium and pH. Alkali soils of IGP are deteriorated to a 

depth of 60-100 cm because of poor quality ground water. 

Characteristics: Alkaline or sodic soils in indo-gangetic plains are generally light to medium 

textured, with CaCO 3 concretion at 0.5-1.0 m depth. These soils have high pH (up to 10.5 in 1:2 





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Page | 61

soil: water suspension) and are poorly permeable with poor soil physical conditions affecting crop 

growth due to nutrient imbalances, low availability / deficiency of N, Zn, Fe, Mn, Mg, and toxicity 

of Na B and Se. The soils are low in organic carbon content and biological activity. At field level the 

observed characteristics are stagnation of water in micro-relief, poor soil physical conditions, 

darker soil surface, and effervescence crusts on the soil surface etc. 

Management of sodic soils: i) improvement of soil condition by chemical reclamation, ii) crop 

choice and genetic modification of plants and iii) cultural/agronomic manipulations 

Reclamation process through amendments with calcium sources of varying solubility 

(gypsum, phospho-gypsum, calcium chloride, ground limestone), acid or acid forming 

substances (sulfuric acid, ferrous sulfate, aluminum sulfate, lime sulfur, iron pyrites, fly ash) 

and organic sources like FYM, GM, compost, crop residues, press mud and molasses, weeds 

like Argimone mexicana, water hyacinth).Being the cheapest gypsum (CaSO 4 2H 2 O) is most 

commonly used. Depending on soil ESP, texture, and soil depth about 4, 8 and 12 tons/ha of 

gypsum is required to ameliorate respectively sandy, clay loam and clay soil of pH 9.6. 

For shallow root crops like rice/ wheat it is recommended to bring ESP to < 10 up to 15 cm 

soil depth. 

The reactivity of gypsum increases with fineness and higher soil ESP. Leaching with saline 

water containing CaCl 2 , CaSO 4 etc., can also be used. 

Pyrite, though cheaper, is only one-fourth as affective as gypsum 

Organic materials promote reclamation through soil physical improvement, mobilization of 

Ca, supply of nutrients, reduction in soil pH, and enhancement of biological activity. 

Sulfitation process press mud is superior. 

Integrated use of chemical amendments, organic matter, critical nutrient inputs, tolerant 

varieties and good cultural / water management practices substantially economize 

reclamation costs (DRR, 2007) and improve soil physical conditions, and availability of plant 

nutrients. 





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Page | 62

Rice is tolerant to alkalinity up to ESP of 50. Continuous growing of rice hastens soil 

reclamation through removal of exchangeable sodium by mobilizing native CaCO 3, 

decreases soil pH through root respiration 

Application of double the dose of Zn (100 kg ZnSO 4 /ha) initially and later normal dose is 

recommended 

Cultural management practices include planting older (>30 days) seedlings, 4-6 

seedlings/hill, deep ploughing up to 100 cm to break hard pans for water movement and 

root penetration, application of 25% more N. 

Improved water uptake and root penetration requires frequent irrigation with less water. 

Tolerant rice varieties such as CSR 13, CSR 23, Vikas, CSR 27, CSR 30, Kalanamak, etc 

enhance rice productivity. . 

Deficiency of iron (Fe) 

Fe deficiency, manifested as interveinal chlorosis / chlorosis of emerging leaves / entire 

plant, is a serious constraint in upland neutral, alkaline and calcareous soils, coarse 

textured soils 

It decreases drymatter production, reduces chlorophyll concentration in leaves and 

reduced activity of sugar metabolism enzymes 

Iron applied to soil are less efficient. Ferrous sulphate, Fe-EDTA and FYM, green manures 

are most commonly used as sprays. Foliar sprays of 1-2% FeSO 4. 7H 2 O solution at weekly 

intervals at early stage of deficiency are quite successful. 

Application of FYM or compost. Ponding of water in nursery beds during dry spell is 

essential to mitigate Fe chlorosis. 

Combination of green manure (GM) or organic manures with foliar spray of 1%FeSO 4 .7H 2 0 

solution is more beneficial in increasing crop yield than GM/ sprays. 

Soil acidity and related Problems 

More than 15 M.ha of rice area in India in the states of Kerala, Karnataka, Goa, North 

Coastal AP, Orissa, Jharkhand, Chhattisgarh, West Bengal, Himachal Pradesh, North east hill 





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egion, Assam and Tamil Nadu have acidic soils of varying degree of constraints associated with 

soil acidity which influence crop productivity 

Characteristics: The soils are coarse - textured with compact surface, poor physical structure and 

aggregate stability, high infiltration rate, low water holding capacity (WHC), high permeability, are 

prone to crusting and compaction (higher bulk density- BD) effecting seed germination. The soils 

have low pH (2.8-6.5), clay fraction with minerals of low surfaces and low CEC, low base saturation 

(16-67%) and high amounts of exchangeable Al, H + , Fe and Mn saturation, high P fixing capacity, 

and general low available status of Ca, K, Mg, P, Mo, B, Si, and high levels of Fe, Al, Mn, Zn, toxicity 

of organic acids, and reduced microbial activity. 

Acid sulfate soils: In coastal lowlands of Kerala and West Bengal soils of high acidity (pH 3.0-3.5) 

and organic matter content (peaty soils) are located. The acid sulfate soils in Kerala, locally known 

as Kari soils (1.1 M ha in Kerala) A part of these in west coast are saline (26,000 ha), and swamp 

soils (2,500 ha) located 2-3 m below sea level. 

Types of soil acidity: The soil acidity is divided into active, exchangeable and non-exchangeable 

(titratable or pH-dependent) forms. The proportion of pH dependant or residual and exchangeable 

acidity determines soil productivity and lime requirement. 

Major production constraints in acid soils: 

Toxic concentrations of Al and Mn have been reported in upland soils with pH below 5.0 

and l leading to impairment of root respiration and growth. . 

Deficiency of bases (Ca, Mg, K) and their poor retention power, and low soil P availability 

and use efficiency due to chemical fixation (up to 90% of applied P). l 

Reduction of soil biological activities 

Fe toxicity in submerged rice. Solubility of Fe increases with decreasing pH, increased OM 

content and water logging with impeded drainage. 





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Management of Acid Soils: 

Liming acid soils (neutralizing H + and Al 3+- pH 5.5) is - economical and selective with 

limestone, burned lime, marl, dolomitic lime, oyster shells, basic slag, cement plant fly dust, 

mining tailings, sugarcane press mud, wood ashes, and paper mill lime sludge categorized 

into carbonates, oxides, hydroxides, and by product materials. 

Lime requirement (LR) depends on initial soil pH, other factors such as surface and subsurface 

soil texture and structure, clay content, CEC, base saturation, OC, crops, kind and 

fineness(30-60 mesh) of liming materials. About 1-2.5 equivalents of exchangeable Al 

would be required to achieve soil pH of 5.5. 

Lime must be uniformly applied and mixed up to 10-15 cm of soil under sufficient moisture 

condition once in 2 years and later at half the rate in areas of >3000mm rainfall, and in 3-4 

years in areas of < 2000mm rainfall. 

Crops differ in their response to lime application. Paddy, potato and small millets are less 

responsive. Rice has tolerance to acidity because of flooding, and is preferred crop. 

P sources of less solubility are less prone to soil fixation and are economical eg., rock 

phosphates to soil of pH < 5.5 or in combination with SSP (1:1 ratio) to soil of pH 5.6-6.5, 

pre kharif green manure or to pulses in rotation(DRR) 

Organic sources / amendments (FYM), either alone or in combination with lime control soil 

acidity, improve nutrient availability and favourably influence microbial activity. 

Iron toxicity in rice 

Iron (Fe) toxicity in rice is widespread in the states of Orissa (42%), West Bengal, 

Chattisgarh, Jharkhand, Kerala, NE and NW hills in acid soils rich in reducible iron, light 

textured, with moderate to high acidity and SOM, low lying fields, low temperatures, salt 

content (acid saline), imbalanced soil nutrient status-deficiency of Ca, K, P, Mg, favour Fe 

toxicity 

Iiron toxicity symptoms are manifested 3-4 weeks after planting as tiny brown spots 

starting from the tips and spreading towards the base of lower leaves. The brown spots 





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coalesce on the interveins, entire leaf looks purplish brown followed by drying- scorched 

appearance. 

Rice plants are more susceptible to Fe toxicity during early growth stages, when root 

oxidation capacity is less. Affected plants have scanty roots, coarse and blunted, and dark 

brown or black (freshly uprooted plants) in colour, stunted growth and poor tillering 

Ameliorative measures include – Partial liming, drainage and addition of green manure or 

compost). Liming may not influence wetland rice crop, but benefits non rice crops 

Apply additional dose of K and P over the recommended level to improve nutrition and root 

health. 

In young acid sulphate soils, liming @ 2-3 t/ha, prolonged submergence and preventing 

water table to fall below the upper limit of pyrite sub-soil and application of phosphate are 

necessary to obtain good yield. 

Delay planting until the peak in Fe2+ concentration has passed (not less than 10–20 days 

after flooding). 

Use intermittent irrigation and avoid continuous flooding on poorly drained soils containing 

large concentration of Fe and organic matter. 

Carry out midseason drainage to remove accumulated Fe2+ at mid-tillering stage (25–30 

DAT/DAS) and keep it free of floodwater for 7–10 days 

Boron (B) deficiency: 

B deficiency occurs in highly weathered, acid upland soils, coarse textured sandy soils, acid 

soils derived from igneous rocks, and in soils of high organic matter and calcareousness 

under moisture stress and dry conditions due to low microbial activity, 

polymerizationptoms 

Affected plants are shorter, emerging (younger) leaves are white with rolled leaf tips, 

increased pollen sterility. The critical soil B level < 0.5 mg B per kg hot water extraction 

On B-deficient soils, apply 1.5 - 3.0 kg B/ha through fertilizer borate (14% B), broadcast and 

incorporated before planting, top dressed, or as foliar spray @ 0.1-0.25% boric acid / 

sodium borate during vegetative rice growth. 





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Basal soil application of B proved superior to foliar sprays. Residual effect of 1.6 kg B ha -1 in 

persists for two to three crops. 

In case of hidden deficiency sprays of 0. 2% boric acid/borax at pre flowering / flower head 

formation stages enhanced the crop yields. 

Sulfide toxicity 

S toxicity occurs in poorly drained (at Eh < -50 mV at pH 7.0) degraded paddy soils with 

low active Fe status, in organic soils, acid- sulphate soils. 

An excessive concentration of hydrogen sulphide (H2S) results in reduced nutrient uptake 

because of a decrease in root respiration. 

Interveinal chlorosis of emerging leaves similar to Fe deficiency, coarse, sparse, and 

blackened roots 

No critical levels have been established. H2S toxicity can occur when the concentration of 

H2S is >0.07 mg per L in the soil solution. 

Deficiency of K (regulates root oxidizing power) and unbalanced crop nutrient status 

aggravates the problem. 

Mid season drainage at the mid tillering stage (25–30 DAT/DAS) for about 7–10 days. 

Apply K, P, lime and Mg fertilizers. Avoid large quantities of organic matter application / 

high BOD sewage sludge, urban wastes etc. 

Dry plough the field after harvest to increase S and Fe oxidation during the fallow period. 





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Conclusions 

Rice and rice based cropping systems are cultivated widely and intensively in India under diverse 

soil and agro ecological conditions consuming major proportion of soil and water resources, agro 

chemicals and fertilizer inputs. The unique system of wetland rice cultivation provided many 

beneficial effects to the crop in terms of nutrient supply, weed and water control, and tolerance to 

specific soil stresses, the system also created problems of soil salinization and water logging of 

many fertile lands in the canal commands because of sharp rise in the water table. Similarly in 

areas of high productivity potential deficiency of many nutrients (Zn, Fe, S, K) have been reported 

after high intensity rice crop systems and high yielding varieties were introduced, which is further 

compounded by imbalanced and indiscriminate application of fertilizers nutrients. The impact on 

the productivity of the system has been perceptible with wide spread occurrence of multi-nutrient 

constraints besides low nutrient use efficiency and factor productivity, resulting in significant 

decline in yield growth under intensive agriculture. Compounded by this discouraging situation is 

the emerging problem associated with climate change influencing through its impact on land use, 

its quality, availability of irrigation water and use efficiency of resources and inputs, and crop 

growth and productivity. 

Adoption of precision technologies for more efficient use of resources and nutrients becomes 

more relevant in the current production scenario. While technological advancements, currently 

available, have the potential to address the issues when implemented in the right perspective of 

sustaining productivity of the soil system on a long term basis, the efforts also require addressing 

few issues connected with cataloguing of available information on soil variability systematically 

using modern tools of remote sensing and GIS. This provides opportunities to integrate crop based 

information for effective management of the field problems and dissemination. Some of the 

important strategies to minimize the existing abiotic stresses and sustain productivity growth 

without deteriorating soil quality are listed below. 





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Page | 68

Refinement of currently available soil test based fertilizer recommendations for rice 

through on-farm studies and cataloguing under GIS environment for effective dissimination 

Extensive adoption of site and yield target-specific integrated nutrient management 

practices involving available organic material, biofertilizers, fertilizers, amendments and 

efficient genotypes 

Restoration of biological activity of degraded and polluted soils through integrated 

methods of soil amelioration involving chemical, biological and cultural (including genetic) 

approaches 

Sequestration of carbon in soil through situation specific management of all available 

organic sources and conservation agriculture to build up soil organic carbon and reduce C 

loss 

Development of precise quantitative models for assessment of soil quality changes under 

different production systems and management and their monitoring for evolving a 

workable soil health care system 

Studies to understand nutrient dynamics and enhance nutrient use efficiency under 

changing climatic conditions 





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Page | 69

References 

ICAR (2008) News reporter April-June 2008 pp 1-2 

NAAS (2006) Low and declining crop responses to fertilizers. Policy paper 35: 1-8 

Tiwari, K,.N.(2007) JISSS 55(4): 444-454 

FAO (2005) Fertilizer use by crops pp: 1-50 

Pal , S.S. et al (2003) Natl. Stmp. In Dev, in Soil Science, Ann. Convn.., Kanpur 

Kar, G et al (2004) Aust, J. Soil Sci. 42: 369-379 

Sen, P et al (2008) Ind. J. Fert. 4:43 – 50 

Naidu, L.G.k.et al (2008) Ind. J. Fert. 4: 47-58 

Jannsen B H et al (1990) Geoderma 46: 299-318 

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DRR (2007, 2008) Progress report: Vol.III Soil Science. 

Swarup,A(2002) Fert. News 47(12):59-73. 

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