SOYBEAN RESEARCH

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Soybean Research 14(2): 32-38 (2016) Nitrogen Use Efficiency in Soybean S D BILLORE 1 and A RAMESH 2 ICAR-Directorate of Soybean Research, Indore 452 001, Madhya Pradesh E mail: billsd@rediffmail.com Received: 13.05.2016; Accepted: 25.10.2016 ABSTRACT Field experiments were conducted for consecutive three kharif seasons during 2011 and 2013 to study the effect of land configuration and nitrogen levels on productivity, nitrogen uptake and nitrogen use efficiency by promising soybean (Glycine max (L.) Merrill) varieties under semi-arid climate of Malwa plateau of Central India. Planting of soybean on broad bed furrow system had superiority over flat bed planting with respect to all the parameters evaluated. Broad bed furrow planting system gave higher yield (5.49 %), nitrogen uptake (5.62 %) and sustainable yield index (0.69) over flat bed planting. Soybean variety JS 97-52 had an edge over JS 95-60 except for seed index and harvest index. Soybean yield increased (8.72 to 15.97 %) as the levels of nitrogen increased up to 40 kg N per ha as basal over control. Basal application of 40 kg N per ha increased the seed yield by 6.68 per cent over recommended basal application of nitrogen (20 kg N/ha). Significantly highest yield, additional yield, net returns, incremental benefit cost ratio, nitrogen uptake and sustainable yield index were recorded with 20 kg N as basal + 40 kg N per ha at R 5 stage. Agronomic efficiency and partial factor productivity decreased as the levels of nitrogen increased while reverse were true with recovery efficiency. All the three nitrogen use efficiencies were maximum with the application of nitrogen @ 10 kg N as basal + 10 kg N per ha at R 5 stage. Key words: Nitrogen level, nitrogen use efficiency, sustainable yield index Increasing soybean yield continues to be an important focus today as input costs and fuel prices are on rise. Producers are progressively facing narrowing of profit margins from soybean and therefore, management decisions are vital for increasing yield and the economic returns. In addition to normal management decisions, producers are exploring the use of fungicides, inoculants, fertilizers and seed treatments to increase yield. Soybean being highly protein rich crop and concomitantly required high amount of nitrogen for producing the 1,2 Principal Scientist high yield as well as protein. However, the biological fixation of atmospheric nitrogen by the soybean plant makes it one of the unique crops grown in the world. The maximum N fixation was observed at starter dose of 20 to 30 kg N per ha. More conservative estimates suggest that the uptake of fixed nitrogen by soybean can meet its 60-89 per cent of total demand (Abendroth et al., 2006 and Rao and Reddy, 2010). The amount of fixed nitrogen used by a plant is often largely dependent on N availability in the soil, with the plants utilizing available soil N prior to fixed N 32
(Salvagiotti et al., 2009). Biological N 2 fixation and mineral soil or fertilizer N are the main sources of meeting the N requirement of high-yielding soybean. A negative exponential relationship was observed between N fertilizer rate and N 2 fixation (Salvagiotti et al., 2009). However, antagonism between nitrate concentration in the soil solution and the N 2 fixation process in the nodules is the main constraint the crop faces in terms of increasing N uptake (Streeter, 1988) and any gaps between crop N demand and N supply by N 2 fixation must be met by N uptake from other sources. However, the generally observed reduction in N 2 fixation activity between the R 5 and R 7 stages (Zapata et al., 1987) could lead to a shortage of N during seed-filling in highyielding environments. Applying fertilizer-N has been proposed as an aid for increasing available N in the soil. Studies of nodulated soybean showed significant yield response to frequent N additions when the N 2 fixation apparatus could not meet N demand (Thies et al., 1995). However, yield response of soybean to fertilizer N has been inconsistent at economically acceptable levels (Gan et al., 2003; Barker and Sawyer, 2005). An important research question is whether fertilizer N can alleviate N limitations without compromising the N 2 fixation capacity of the crop and doing so in a cost effective manner. Majority of soybean acreage is on Vertisols and associated soils. Soybean being a rainfed crop in India it experiences the moisture stress in its life cycle. The land configurations may be help under such situation. The yielding ability of soybean varieties was found to differ substantially because of their genetic makeup. The objective of the present research was to evaluate the effects of late-season supplemental N on soybean grain yield and nitrogen use efficiency of soybean varieties under different land configurations. MATERIALS AND METHODS A field study was carried out during kharif seasons between 2011 and 2013 at research farm of ICAR-Indian Institute of Soybean Research, Indore on Typic Chromusterts. The soil of experimental site analyzed: pH, 7.86; EC, 0.14 dS/m; organic carbon, 0.30 per cent; available P and K 4.80 and 120 kg per ha, respectively. The treatments included two land configurations (Broad bed furrow – BBF and flat bed system), two soybean varieties (JS 95-60 and JS 97-52) and 6 levels of nitrogen, namely, 0, 20, 40, 10 (basal) + 10 (at R 5 stage- pod filling), 20 + 20, and 20 + 40 kg N per ha. The design of the experiment was strip plot with three replications at a fixed site. The plot size was 3.6 m x 6 m. Uniform recommended dose of phosphorus (60 kg/ha) and potassium (20 kg/ha) were applied to all the treatments. The crop was planted on the onset of monsoon and grown as rainfed. The recommended package of practices was adopted for raising the soybean crop during the experimentation. Nitrogen uptake of seed and straw of soybean (kg/ha) was 33
Page 1 and 2: ISSN 0973-1830 Volume 14, Number 2
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Page 5 and 6: Soybean Research 14(2): 01-13 (2016
Page 7 and 8: Table 1. Nutrient composition (valu
Page 9 and 10: 100-green seed weight (49.9 g) and
Page 11 and 12: Training was provided through NGO p
Page 13 and 14: estimated using combined analysis.
Page 15 and 16: AGS 447 and AGS 457 in a taste surv
Page 17 and 18: Takahashi Y and Ohyama T. 2011. Pro
Page 19 and 20: eached to about 81,4435 ha in 2013
Page 21 and 22: 2. Soybean seeds were sown in both
Page 23 and 24: Table 1. Effect of ridge width, cro
Page 25 and 26: Table 3. Effect of ridge width, cro
Page 27 and 28: and seed yields per ha were affecte
Page 29 and 30: number of branches per plant, pod a
Page 31 and 32: cv. Giza 35 to increase dry matter
Page 33 and 34: increased total and net returns com
Page 35: Metwally A A. 1999. Intensive coppi
Page 39 and 40: Table 1. Effect of land configurati
Page 41 and 42: increasing levels of nitrogen and t
Page 45 and 46: conditions (Ruiz-Lozano et al., 200
Page 47 and 48: of 34 0 C and relative humidity 80
Page 49 and 50: Nodule N (%) Grain yield g/plant) N
Page 51 and 52: 140 120 100 Nodules/plant Nodule dr
Page 53 and 54: of AMF, which necessitates experime
Page 55 and 56: Biermann B and Linderman R G. 1981.
Page 57 and 58: Tabatabai M A and J M Bremner. 1969
Page 59 and 60: N:P 2O 5:K per ha (Patil and Purani
Page 61 and 62: available nitrogen content was reco
Page 63 and 64: lowest value in control (Table 2).
Page 65 and 66: the crop. These results corroborate
Page 69 and 70: the use of a variety by any person
Page 71 and 72: objection is received, the variety
Page 73 and 74: Table 1 contd. S. No. Name of varie
Page 75 and 76: Table 2. DUS Characteristics of pro
Page 77 and 78: Table 2. Contd S. No. Varieties DUS
Page 79 and 80: and are easily available. The varie
Page 83 and 84: Table 2. Estimates of variability p
Page 85 and 86: Table 4. Phenotypic path coefficien
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Shivakumar M, Basavaraja G T, Salim
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available phosphorus (24.89 and 23.
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attributes may be the result of red
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Soybean Research 14(2): 89-96 (2016
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productivity. This will help increa
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Growth rate The analysis on growth
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Table 5. Estimates of variability i
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Society for Soybean Research and De
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MS must be original and contribute
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Short research notes They should no
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