Evaluatio of Current Micronutrient Stocks in Different Agro-Ecological Zones of India for Sustainable Crop Production

摘要

The paper aimed to delineate micronutrient deficient agro-ecological zones of India. Scrutiny of 1.48 lakh soil samples data of recent years for different agro-ecological zones (AEZ) and soil types indicated 45, 8.3, 4.5, 3.3 and 33 per cent mean deficiency of Zn, Fe, Mn, Cu and B, respectively as compared to those of 49,12, 5, 3 per cent of Zn, Fe, Mn and Cu found based on compilation of data of 2.52 lakh soil samples collected during 1967-97 representing soils of 20 states.Zinc deficiency in different zones was less than 40% in AEZ 1, 2, 5,15,16,18, tford 19; 40-50% in AEZ 9,11,12; 50-55% in AEZ 4, 7,13 and >55% in remaining other zones. Among 90419 surface soil samples analysed for AEZ 4, 9,13,16mainly for Indo-Gangetic alluvial plain (IGAP) showed 55, 47 and 36% zinc deficiency in Trans-northern, Central and Eastern parts of IGAP while reverse trend was found for boron showing 8, 37, 68% deficient soils, respectively. Boron deficiency varies from 2% in AER 2; 24-48% in highly calcareous soils of AEZ 2,9 and 14 but most widespread (39-68%) in red and lateritic soils of AEZ 6,13,16,17, 19. Deficiencies of Cu and Mn were found sporadic. Zinc deficiency initially was more in Trans northern IGP alluvial plains than in recent alluvial soils of eastern plains which is decreasing with time due to regular use of zinc fertilisers.However, multinutrient deficiencies are emerging in several specific soil or AEZ. The problem of iron and manganese has emerged in Trans-northern IGAP zone 4 and 9, more so in areas under rice-wheat than cotton-wheat or cereal-oilseeds based cropping systems. Most soils have tested to be adequate in available iron;but its deficiency in all AEZ as well as toxicity in some coastal, submontane and red lateritic soils is quite common. The paper summarises occurrence of micronutrient deficiencies amongest and within Agro-ecological zones and magnitude of crop response for formulating suitable micronutrient management strategies for specific AEZ, soil types and cropping systems for maximizing crop oroduction.