Micronutrients Availability in Soil–Plant System in Response to Long-Term Integrated Nutrient Management Under Rice–Wheat Cropping System

Abstract

In this study, we investigated the effect of long-term integrated nutrient management (INM) involving chemical fertilizers and organic amendments viz. farmyard manure (FYM), green manure (GM), and paddy straw (PS) on the availability of micronutrients in soil, their uptake by plants, and crop yield for rice–wheat system. Soil availability of micronutrients and their plant tissue concentrations was estimated in grain and straw of both the crops. Soil recovery coefficient (SRC) and transfer coefficient (TC) were calculated to find out micronutrients availability in relation to their plant uptake and transfer of micronutrients from shoot to grain, respectively. Results revealed that integration of FYM proved significantly superior to GM and PS in improving organic carbon, micronutrients availability, and shoot to grain transfer (TC) of Fe (both the crops) and Mn (wheat). Low SRC values of Zn, Cu, Fe, and Mn indicated that long-term INM can meet their plant nutritional requirement in rice–wheat system. However, higher SRC values for B (0.49) in 100% NPK treatment as well as in the integrated ones (0.22–0.27 for rice, 0.23–0.28 for wheat) suggest that quantity of this element in soil was too low to meet plants nutritional needs which was also confirmed by its very low content in the soil (below critical levels, i.e., 0.5 mg kg−1). This study concludes that long-term integration of FYM (with NPK fertilizers) has an edge over GM and PS in regulating the supply of micronutrients in soil–plant system and correcting the micronutrient deficiencies (except B) in rice–wheat cropping system.