改善农学管理措施减少太湖稻麦轮作NH_3和NO排放

Improving Agronomic Practices to Reduce Ammonia and Nitric Oxide Emissions from Rice-wheat Rotation Field in Tai Lake Region,China

在太湖稻麦轮作体系下,采用密闭室-间歇通气法和静态箱-化学发光法对空白(不施氮肥)、当地常规(农民习惯管理方式)和保产增效(与当地常规相比,改善作物种植、水分和养分管理方式)3个田间小区下的氨(NH_3)挥发和一氧化氮(NO)排放通量进行原位观测,并对作物产量和氮利用率进行评价。结果表明:与当地常规处理相比,保产增效处理在施氮量减少25%的情况下,总作物产量没有降低,且农学利用率提高了39%;NH_3挥发量在稻季和麦季分别减少了26%和44%;NO排放量在稻季较低(N,(0.75±0.03)kg/hm^2),与空白和当地常规处理均没有显著差异(P<0.05),但在麦季则显著降低了49%。因此,保产增效措施不仅能保障高产和提高氮利用率,还能减少NH_3和NO排放,值得在太湖地区推广。

Winter wheat-summer rice rotation is one of the general cropping systems in the Tai Lake Region, China, but which is favor ammonia （NH3） and nitric oxide （NO） emission to atmosphere due to high N input with low N use efficiency （NUE）, thus it is necessary to improve the agronomic management practices to alleviate the detrimental impacts of these gaseous compound emissions. This study is to illustrate the effectiveness of an improved integrated crop cultivation, water and nutrient practice for mitigating NH3 and NO emissions. Dynamic and static chambers were employed to simultaneously estimate NH3 and NO emissions from a rice-wheat rotation field with three different treatments of 1） CK （control, without N input）, 2） FP （the famer＇s practice）; and 3） IP （the improved crop cultivation, water and nutrient management practice with nitrogen dose reduced by 25% compared to FP in the Tai Lake Region. Crop yield and agronomic N use efficiency （ANUE） were appraised. In the rice-wheat rotation, the total crop yield from IP treatment was consistent with FP, and ANUE increased by 39% （P〈0.05）. Compared to FP, IP in the rice and wheat seasons mitigated seasonal NH3 emissions by 26% and 44%, respectively. In meanwhile, IP emitted marginal NO （N 0.75±0.03 kg/hm^2） into the atmosphere in rice growing season, which was in consistent with CK and FP. Besides, IP decreased NO emission by 49% in wheat growing season. Thus, IP practice should be advocated in this region for it sustaining crop yield and decreasing the environmental risk by mitigating significantly NH3 and NO emissions at the same time.