Estimation of nitrous oxide emission from pulse cultivation in rainfed uplands.

摘要

An experiment was conducted in Sorada and Tangibanta, Orissa, India, on black gram (BG), horse gram (HG) and green gram (GG) for: estimation of N₂O from cultivation of different pulses; determination of factors affecting N₂O emission from these pulses; and the role of these crops in the emission of N₂O. Maximum emission of N₂O occurred in BG just before flowering at both places. However, N₂O flux in Tangibanta was always higher than at Soroda.For GG, the maximum N₂O emission occurred during 20-40 days after sowing. N₂O emission was also higher in Tangibanta compared to Soroda. N₂O flux was also collected during HG cultivation in both places. In most of the cases, positive N₂O flux was observed. Maximum flux was observed after 56-70 days of sowing in both the places. pH of the soil was near neutral or slightly acidic throughout the cropping period. In all the cases, redox potential of the soil was positive throughout the measuring period. The soil carbon content ranged from 4 to 6 g/kg. N₂O emission from agricultural activities depends on various factors such as N content, moisture content, pH, redox potential and temperature. The NO-₃, NO-₂ and NH+₄ content in the soil at Soroda was lower than that at Tangibanta. In both the places, the highest N₂O emission was associated with the higher N content of the soil.The seasonally integrated flux was observed to be different for different crops.