Priority Zoning of Available Micronutrients in the Soils of Agro-ecological Sub-regions of North-East India Using Geo-spatial Techniques

Abstract

An attempt was made to identify priority zones of available micronutrients in the soils of agro-ecological sub-regions (AESR) of north-eastern states of India (Assam, Nagaland, Sikkim and Tripura) using geo-spatial techniques. Surface soil samples (0–25 cm) were collected from Assam (AESRs 15.2, 15.3, 15.4 and 17.1), Nagaland (AESR 17.1), Sikkim (AESR 16.2) and Tripura (AESR 17.2) and analysed for pH, organic carbon and DTPA-extractable micronutrients (Fe, Mn, Zn and Cu) by standard procedures. Regular Spline was employed as spatial interpolation techniques for obtaining spatial distribution of available micronutrients in soils. The AESR map was overlaid on spatial distribution layers to obtain spatial variability of micronutrients in the AESRs of north-eastern regions of India. Zinc deficiency was common in all the AESR. Maximum deficient area of Zn, Mn and Cu was observed in AESR 15.4, and it was regarded as the high-priority zone, whereas AESR 16.2 and AESR 17.2 were considered as low-priority zone. Rainfall, pH and organic carbon appeared to be the key factors in controlling micronutrient availability in soils of north-eastern regions of India.