Soil health and crop productivity.

摘要

Soil health emphasizes the integration of biological, chemical and physical measures of soil quality that affect farmers profit and the environment. Healthy soil, an essential component of a healthy environment, is the foundation upon which sustainable agriculture is built. Soil quality or soil health can be defined as "the fitness of soil for use" that has both inherent and dynamic components. The indicators of soil quality cover the whole range of soil physical, chemical and biological properties and the key soil quality indicators are soil texture, bulk density, aggregation, available water capacity, pH, EC, available soil nutrient reserves, organic C, microbial biomass, number of earthworms and termites. Major issues of soil health under Indian context include: (i) physical degradation caused by compaction, crusting, puddling, water logging and soil erosion, (ii) chemical degradation caused by wide nutrient gap between nutrient demand and supply, high nutrient turn over in soil-plant system coupled with low and imbalanced fertilizer use, emerging deficiencies of secondary and micro nutrients, poor nutrient use efficiency, insufficient input of organic sources because of other competitive uses, acidification and aluminium toxicity in acid soils, salinity and alkalinity, (iii) biological degradation due to organic matter depletion and loss of soil fauna and flora, and (iv) soil pollution from industrial wastes, excessive use of pesticides and heavy metal contamination. Management options to overcome these problems include the amelioration of soil physical environment, enhancing soil chemical and biological qualities through Integrated Plant Nutrition System (IPNS), soil test based fertilizer recommendation, micronutrient fertilization, management of industrial wastes and poor quality waters for agricultural use.