Long-Term Effect of Crop Residues and Zinc Fertilizer on Crop Yield, Nutrient Uptake and Fertility Build-up under Rice-Wheat Cropping System in Calciorthents

The effect of crop residues and zinc fertilizer on grain yield and nutrient uptake by rice and wheat was studied after 12 years of crop cycles in a Calciorthent. Long-term application of crop residues along with zinc increased soil organic carbon (from 4.5 to 6.8 g kg⁻¹), grain yield (3.40 to 4.35 t ha⁻¹ rice and 3.0 to 3.92 t ha⁻¹ wheat) and nutrient uptake by rice (191 to 405 g Zn, 68 to 98 g Cu, 2159 to 2717 g Fe and 663 to 1038 g Mn ha⁻¹) and wheat (142 to 256 g Zn, 53 to 84 g Cu, 1235 to 1679 g Fe and 411 to 659 g Mn ha⁻¹). The highest grain yield in both the crops was recorded in the treatment receiving 10 kg Zn ha⁻¹ along with 100% incorporation of the straw produced by both the crops. The treatment consisting of 5 kg Zn ha⁻¹ + 100% of crop residues was the next promising treatment in enhancing the crop yields. The combined use of crop residues and zinc fertilizer significantly increased the availability of N, P, K and micronutrients in soil over zinc-application alone. The application of 50% crop residues along with 5–10 kg Zn ha⁻¹ was adequate in sustaining crop productivity and maintaining soil health.