Effect of organic amendments with varied C-N ratios on grain productivity and nitrous oxide (N2O) emission from wheat grown in alluvial soil

Abstract

Amendment of local organic residues has been gaining worldwide attention for mitigation of agricultural greenhouse gases. Four treatments having different C-N ratios, including conventional Nitrogenous fertilizer (NPK), Cow dung (C:N = 25:1), Rice straw (C:N = 41:1) and Poultry manure (C:N = 15:1) were applied in the field to measure nitrous oxide emission from wheat (Triticum aestivum) crop variety Sonalika. The static chamber method and gas chromatography were employed for the collection and analysis of N2O. The cumulative N2O emission flux (Esif) recorded for the first year 2010-2011 were 1.78, 1.34, 1.46 and 1.83 kg N2O- N ha-1while for 2011-2012 it was 1.95, 1.36, 1.77 and 1.88 kg N2O - N ha-1 for NPK, CD, RS and PM, respectively. In this study, application of cow dung resulted in lower seasonal N2O emission than conventional N-fertilizer application for both the years. The N2O emissions from different treatments exhibited a strong correlation (p < 0.01) with soil organic carbon (R11 = 0.7763 and R12 = 0.652), soil mineralized N, NH4+-N (R11= 0.5517 and R12 = 0.8424 and NO3- -N (R11= 0.814 and R12 = 0.8579) plant height and tiller numbers (R11 = 0.565 and R12 = 0.723, p < 0.01). Highest yield was recorded at poultry manure (PM) applied field (3.10 and 3.82t ha-1). Application of cow dung with C:N = 25: 1 in wheat field reduced N2O emission and may be considered a suitable treatment for mitigation of N2O from Wheat agriculture without compromising grain productivity.