Seed Health Management for Better Productivity - Govind Ballabh ...

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(Seed Health Management for Better Productivity)Soil Health and Quality Seed ProductionB. MishraDepartment of Soil Science, G.B.P.U.A.&T., Pantnagar-263145 (Uttarakhand)Soil health may be viewed as the component of ecosystem health that reflects theproperties of soil as a living system. In simplest terms, soil health can be defined as "the fitness ofsoil for use" (Doran et al. 1996). In agricultural systems, healthy soil provides for the sustained andproductive growth of crops with minimal impacts on the environment.Soil is a component of primary importance in crop production, even if it is often neglected,or only regarded as a physical support for the growth of plants. However, with the increasingconcerns for the sustainability of agriculture and environmental protection, soil must be consideredas a living system. Its quality results from the multiple interactions among physicochemical andbiological components, notably the microbial communities, primordial for soil function. Crops areaffected by soil health and threatened by soil-borne diseases.The terms “soil health” and “soil quality” are often used synonymously. However, soil healthmay be considered as the state of soil at a particular time with reference to benchmark soil,whereas soil quality refers to its ability to function for a specific purpose. Two soils may be equally“healthy” but may achieve different levels of plant productivity because of differences in theirinherent quality.There are two components of soil quality viz. inherent and dynamic. Inherent soil qualityrefers to the characteristics that define a soil’s inherent capacity for plant production. These areusually static, changing little over short time frames (years to decades). Soil texture and soilmineralogy are commonly included as properties of inherent soil quality for productivity. Other soilproperties such as total soil carbon, cation exchange capacity (CEC) and exchangeable sodiumpercentage (ESP) may also be considered as inherent properties, even though they may bealtered by management over longer time frame.Properties of dynamic soil quality are those that change in response to human use andmanagement normally over relatively short time frame (years to decades). Agricultural soils of highquality or good health maintain high nutrient availability, permit adequate infiltration of water andair, have relatively stable structure and maintain a functionally diverse community of soilorganisms that support a relatively high level of plant productivity. These processes are reflectedin specific physical, chemical and biological properties of soils.It is not feasible to measure all soil properties in order to assess the soil quality or health.Some indicators are needed to facilitate the measurement of soil quality. These indicators coverthe whole range of soil physical, chemical and biological properties, reflect soil functions, and areeasy to measure for a variety of users and under various field conditions, and respond to changesin climate and management. Table 1 lists a set of indicators that are commonly used tocharacterize soil quality or soil health. Key indicators are soil texture, bulk density, aggregation,- 62 -
(Seed Health Management for Better Productivity)available water capacity, pH, EC, NPK reserves, organic C, and microbial biomass. In specificsituations, additional soil properties may be identified as indicators e.g. soil aggregation, ESP,micronutrient status, pesticide residues and heavy metal pollutants.Table 1: Some soil physical, chemical and biological properties used as indicatorsof soil healthSoil propertyPhysical propertiesSoil textureTopsoil and rooting depthSoil bulk densityInfiltration, hydraulicconductivityWater contentWater holding capacity,water release curveChemical propertiespHElectrical conductivityAvailable N, P, KOrganic C and NBiological propertiesInformationRetention and transport of water, nutrients and chemicals,susceptibility to erosion; stabilization of organic matter and soilstructureWater and nutrient availability, rooting volume for crop productionVolume of pore space, compactionRunoff and leaching potential, drainageAvailable waterAvailability of air and water, retention and transport of water andchemicals, drainageAcidity or alkalinity of soil, nutrient availabilityPresence and quantity of soluble saltsPlant available nutrientsOrganic matter reserves, nutrient cycling, soil structurePotentially mineralizable NMicrobial biomassSoil respirationPotential to supply plant available NSize of microbial population, pool of rapidly cycling organic matterand nutrientsAvailability of soil organic matter reserves, microbiological activitySoil productivity can certainly be lost through erosion, nutrient mining or other processessuch as salinization, sodification, compaction and water logging. The linkage between soilproductivity and soil health or quality is apparent when changes in soil attributes used to assesssoil quality are linked to causes of productivity loss. The effects of management practices onproductivity can also be assessed using soil quality attributes.Building or restoring soil health or quality may involve a range of measures adopted at thefield, farm or watershed level, to optimize resource conservation. Integrative approaches to landuse, such as conservation tillage and organic farming have shown that management inputs (e.g.crop residues) and system diversity (e.g. crop rotation) strongly influence dynamic soil properties.Recently, favorable effects of integrated nutrient management on soil quality indicators have beenreported (Sharma et al. 2005).Agricultural practices that affect soil health/quality1) Soil conservation2) Tillage3) Addition of organic matter (manures, crop residues)4) Use fertilizers and agrochemicals- 63 -
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potential. An improvement in qualit
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9. Session Arrangement CommitteeDr.
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9. Dr. Pradip Kumar BorahSr. Scient
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TRAININGONANNEXURE-IIISEED HEALTH M
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ANNEXURE-IVCENTRE OF ADVANCED STUDI
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SundayApril 6MondayApril 7TuesdayAp
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