Long-term Effect of Integrated Nutrient Management on Distribution of DTPA-Extractable Micronutrients in Typic Haplustept under Rice-Wheat System

摘要

Soil samples collected from an on-going experiment on rice-wheat cropping system were analyzed to study the effect of manure and chemical fertilisers on distribution of DTPA-extractable zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in Typic Haplustept. Biogas slurry (BGS) was used as an organic source incorporated @ 6 t ha~(-1) before rice transplanting. Nitrogen (80 and 120 kg N ha~(-1)) and phosphorus (30 kg P2O5 ha~(-1)) in different combinations were applied to rice. Potassium @ 30 kg K2O ha~(-1) was uniformly applied to rice. In this study higher contents of DTPA-extractable Zn (3.37 to 5.73 mg kg~(-1)), Cu (0.88 to 1.36 mg kg~(-1)), Fe (24.81 to 44.10 mg kg~(-1)) and Mn (16.87 to 30.03 mg kg~(-1)) were obtained in surface soil samples collected before sowing of wheat. In the samples collected after harvesting of rice crop, levels of DTPA- extractable Zn, Cu, Fe and Mn contents ranged from 3.85 to 5.57, 1.38 to 1.77, 48.09 to 71.10 and 9.97 to 15.85 mg kg~(-1), respectively.