ĐÁNH GIÁ MỨC ĐỘ PHÁT THẢI CH4 TỪ ĐẤT PHÙ SA SÔNG HỒNG VÀ ĐẤT XÁM BẠC MÀU TRỒNG LÚA Ở MIỀN BẮC VIỆT NAM
ĐÁNH GIÁ MỨC ĐỘ PHÁT THẢI CH4 TỪ ĐẤT PHÙ SA SÔNG HỒNG VÀ ĐẤT XÁM BẠC MÀU TRỒNG LÚA Ở MIỀN BẮC VIỆT NAM
Assessment of CH4 emission from rice - growing fluvisols and acrisols in North Vietnam
Rice soils is a major emission source of CH4, the important greenhouse gas causing global warming. CH4 emission from rice soils is affected by agronomic and environmental factors. Therefore eveluation of CH4 emission potential of different rice production systems is required. In a pot experiment conducted in IAE, Hanoi, CH4 emission from fluvisols or acriosols cultivated with rice (Khangdan 18) with or without fertilizer application was observed and also checked in actual rice fields. The study shown that cumulative CH4 emission per unit of area (CCE/A) was 9% higher, but cumulative CH4 emission per unit of grain commodity (CCE/C) was 57% lower, in fluvisols than those in acrisols when not applied with fertilizer. Fertilizer application at the popular rate increased CCE/A by 15.4% and 25.5% while it decreased CCE/C by 30% and 59% in fluvisols and acrisols, respectively when compared to controls without fertilizer. In both soil types, CCE/A in Spring rice crop higher that in Summer rice crop (44489 - 45061 vs. 33454 - 39718 mgC m - 2 ) but CCE/C between two the rice crops did not differ statistically (84.3 and 93.7 mgC/g). The highest CH4 emission intensity occured in 45 - 60 days after transplanting. These results suggested that CH4 emission from different soil types differ but this can be overshadowed by difference in cultivation techniques and climate. Further studies on effect of cultivation techniques on CH4 emission from different soil types are essential.