Integration of Organics in Nutrient Management Improves Micronutrient Profile of Soil and Plants: A Case Study of Rice-Wheat Systems in Indo-Gangetic Plain

Organic Nutrient Management Improves micronutrient profile in Rice-Wheat Systems

Abstract

Incidences of micronutrient in human beings is an emerging challenge at global scale. Crop plants are the major source of micronutrients in the human diet via either direct consumption of plant parts or indirectly through the use of dairy and meat from animals fed on fodder and crop residues. In a 10-year long experiment on soil nutrient management for the rice-wheat cropping systems, the effects of six common managements on the daily plant availability of Zn, Fe, Cu, their stocks in soil, and the translocation into grain and straw were studied. The management included: 1) F=100% inorganic macronutrient (N, P, K) and micronutrient (Zn) fertilizers compared to reduced macronutrient fertilizer (55% of N, P, K; no micronutrient) application supplemented with organic inputs from 2) LE=opportunity legume crop (Green gram; Vigna radiata) biomass incorporation, 3) GM=green manuring with Sesbania aculeata, 4) FYM=farmyard manure incorporation, 5) WS=wheat stubble incorporation, and 6) RS=rice stubble incorporation. In the case of 100% inorganic nutrient management (F), significant soil buildup of micronutrient Zn neither translated into proportionate availability in soil solution during crop growth nor improved translocation to plant parts. All organic supplemented management, particularly legume-based, resulted in higher availability of Zn, Fe, and Cu in soil solution during crop growth, and better translocation into plants, compared to 100% inorganic fertilizer use. Total zinc harvests in legume based organics integration in nutrient management are comparable with zinc fertilization. Rice and wheat serve, almost in the whole world, as a staple food and their straw serves as feed for animals in many regions. The study indicated to considerable improvement in micronutrient status of rice-wheat crops when grown with integration of organics in nutrient management. Thus, integration of organic inputs has the potential to improve the micronutrient nutritional quality of rice-wheat crops and may contribute to addressing micronutrient deficiency, while recognizing that confirmation of effects on human nutrition would require dedicated dietary and nutritional studies.