Nitrous Oxide Emissions from Soils Differentially Fertilized with Fertilizers and Manures Under Long-Term Rice-Wheat Cropping System in Northern India.

Differential long-term application of fertilizers and manures under continuous rice-wheat cropping system may result in changes in the soil carbon and nitrogen dynamics, which in-term may influence the emission of nitrous oxide (N₂O) from soils. A long-term fertilizer experiment under rice-wheat cropping system, in progress for past 18 years at Punjab Agricultural University, Ludhiana, India, was selected to study the effect of continuous application of chemical fertilizers in conjunction with green manure, farmyard manure and straw on N₂O emission from soils during rice and wheat growing seasons. N₂O fluxes varied considerably during the rice season under various treatments and were the highest under alone nitrogen application treatments and varied from 0.08 to 1.89 mg m^-2 h^-1 and were the lowest in control treatments. During wheat growing season N₂O emission was the highest under 150% NPK treatment, and least under control treatment.