Assessment of Available Macro and Micronutrient Status in Soils of Dhubri District of Assam

Abstract

An investigation was carried out to study fertility status in soils of Dhubri district of Assam and their relationship with some important soil properties. A total of two hundred and eighty geo-referenced surface (0-15 cm) soil samples were analyzed for macronutrients, micronutrients and some important soil properties. Soils of the district were found to be extremely acidic to slightly acidic in reaction with a low to high organic carbon (OC) content and low in cation exchange capacity (CEC). Status of available nitrogen (N) and potassium (K) was found to be low to medium category, while, in case of phosphorus (P), it was found low to high category. The overall per cent sample category of available sulphur (S) under low, medium and high was 6.99, 7.04 and 85.9%, respectively. All soils were adequately supplied with DTPA-extractable iron (Fe), manganese (Mn) and copper (Cu) content. In respect of zinc (Zn), 90.7% was sufficient, while, all soils were found deficient in hot water soluble boron (HWS-B). The overall nutrient index values of N, P, K, S, Zn, Fe, Cu, Mn and B were 1.67, 1.78, 1.73, 2.78, 2.34, 3.00, 3.00, 3.00 and 1.00, respectively. The overall fertility rating was low for B, medium for major nutrients and high for S, Zn, Fe, Cu and Mn. Soil pH and EC showed positive significant correlation with macronutrients and negative correlation with micronutrients. The macro and micronutrient showed significant positive relation with soil OC and CEC.