Role of soil physical properties in soil health management and crop productivity in rainfed systems-I: Soil physical constraints and scope.

Soil physical degradation has become a serious problem in both rainfed and irrigated areas of India. According to an estimate, about 90 m ha area is experiencing soil physical constraint in the country. In rainfed regions, among several other constraints related to crop and climate, soil physical constraints are the key which severely limit crop productivity. The predominant soil constraints which are governed by the principles of soil physics include subsurface hard pan and compactness, crusting and hardening, slow and high permeability, non-optimal porosity, poor soil structure, poor water receptivity, retention and transmission, etc. It is now well-established that unless the soil physical environment is maintained at its optimum level, the genetic yield potential of a crop cannot be realized even when all the other requirements are fulfiled. The optimum soil physical environment creates a suitable condition for better crop production both in irrigated and rainfed regions. Rainfed agriculture, often referred to as dryland agriculture, is practiced in areas that are relatively warmer (arid, semi-arid) and dry sub-humid regions of the country. These regions are highly diverse, ranging from resource-rich areas with good agricultural potential to resource-constrained areas with a much more restricted potential. These regions represent a wide variety of soil types, agro-climatic and rainfall conditions. This article discusses the soil physical constraints in rainfed regions of India. [ABSTRACT FROM AUTHOR]