Impact of Long-Term Organic Manure Application on Yield, Zinc, and Copper Uptake in Maize, Peas, and Mungbean (Vigna radiata L.) Cropping System

Abstract

To evaluate the impact of the long-term application of organic manures on yield, uptake of zinc and copper in maize, peas and summer mungbean cropping systems, a field study was conducted at the integrated farming system of Punjab Agricultural University, Ludhiana. The treatment combinations were; T₁: 50% N through recommended NPK + 50% N was substituted through FYM, T₂: 100% N through FYM, T₃: T₂ + intercropping (marigold in pea, cowpea in maize), T₄: T₂ + agronomic practices for weed and. pest control, T₅: 50% N as FYM + rock phosphate to substitute the P requirement of crops + phosphate solubilizing bacterial. cultures (PSB), T₆: T₂ + biofertilizer (consortium) containing N and P carriers and T₇: 100% Recommended NPK through chemical fertilizers. Significant increases in the yield, micronutrient content and uptake were recorded due to the application of 50% nitrogen through farmyard manure (FYM) and 50% of the recommended dose of fertilizers (T₁) followed by 100% N through FYM + biofertilizer containing. N and P_, carriers (T₆). The highest grain yield of maize (5.72 t ha^-1), pea (16.2 t ha^-1) and summer mungbean (11.6 t ha^-1) were recorded in treatment T_1, surpassing the 100% recommended dose of fertilizer (T7) by 13.7%, 20% and 10.4 %, respectively. The concentration of copper (Cu) and zinc (Zn) in the grains of maize, pea and summer mung bean was 38.3%, 14.1%, 29.6% and 53.4%, 22.8 % and 19.8% higher in treatment T₁ as compared to treatment T_7. Moreover, the concentration of copper and zinc in the grains of maize, pea and summer mung bean was 32.1%, 24.2% and 29.5 % and 21.7%, 17.6% and 11.6% higher in treatment T₁, respectively, compared to treatment T₇. Similarly, the increase in the uptake of Cu and Zn was observed in both grain and straw of maize, pea and summer mung bean. The study concluded that the integrated nutrient management (INM) treatment is to substitute a portion of chemical fertilizers with a more sustainable and environmentally safe organic compost in order to mitigate soil degradation, improve crop production, and protect the environment.