Revisiting the agro-ecological zones for crop evaluation

Abstract

Food and nutritional security on sustainable basis are the major challenges of the 21st Century. The domestic production needs to be increased @2% for cereals and pulses and 0.6% per annum for oilseed to meet the projected demand by the year 2030. The speed of the expansion of irrigation potential of 140 m ha is very tardy at present. Irrigation has been possible in only 83 m ha upto 2005-06. Improving the efficiency of water under rainfed situation holds a promise to increase the productivity. Frontline demonstration results showed a large gap between farmers’ yield and achievable yield. This gap can be filled considerably by adopting a sustainable management approach of natural resources. It requires knowledge of sound agronomic principles, broader understanding of constraints and interaction of biotic and abiotic stresses in developing crop genetic bases for diversifying production while ensuring the efficiency of resource use. Under rainfed conditions, the yield of deeprooted crops in cracking clay soils (Vertisols) depends primarily on the amount of rain entered and stored at depth in soil profile, and the extent to which this soil water is released during the crop growth. Recent research results obtained at NBSSandLUP [16, 17, 19] indicate that both retention and release of soil water are governed by the nature and content of clay minerals, and also by the nature of exchangeable cations. In arid and semi-arid environment the subsoils become sodic due to accelerated rate of formation and accumulation of pedogenic CaCO3. This process impairs the sHC. Therefore, it has become imperative to revise the AESR boundaries incorporating revised LGP estimates based on soil properties. AESR map is a useful tool to plan the crop suitability based on length of growing period. The revision of LGP estimates involving the influence of drainage related soil properties might provide a better insight into the AESRs. It might also involve revising AESR boundaries to bring the latest soil, climate information generated during the last 20 years.