灌溉和种植方式对双季稻田NH3挥发和N2O排放的影响

Effects of irrigation and planting methods on ammonia volatilization andnitrous oxide emissions from double-cropping rice

【目的】探究种植和灌溉方式对双季稻全生育期水分利用效率以及氮素气态损失的影响。【方法】以双季稻田为研究对象,在江西省灌溉试验中心站研究基地开展大田试验,设置手工栽插(HT)、机械插秧(MT)、抛秧(ST)、直播(DS)四种种植方式,淹水灌溉(FI)和间歇灌溉(II)两种灌溉方式,分析不同种植和灌溉方式对双季稻全生育期水分利用效率以及秧田期、本田期NH3挥发及N2O排放的影响,提出NH3挥发和N2O排放的主要时期。【结果】结果表明:(1)与传统淹水灌溉相比,间歇灌溉下水稻产量略有增加,不同种植方式间产量差异显著,HT最高,DS最低。(2)同一种植方式下,间歇灌溉下N2O排放量较淹水灌溉增加约7.9%~16.4%,同一灌溉方式下,早稻N2O损失量大小为DS>MT>HT>ST,晚稻为DS>HT>MT>ST,早、晚稻N2O排放主要发生在分蘖期、拔节孕穗期、成熟期,3个生育阶段N2O损失量占比超过70%,而育秧期MT、ST占比不到1.5%,HT为6.4%。(3)同一种植方式下,早、晚稻NH3挥发损失量淹水灌溉比间歇灌溉增加了3.0%~30.8%,同一灌溉方式下,DS相比移栽稻显著增加NH3挥发(P<0.05),HT、MT、ST之间无显著差异,NH3挥发峰值均在施肥后3 d内出现,且主要发生在苗期、分蘖期、拔节孕穗期3个时期,其NH3挥发损失量之和占整个生育期NH3挥发损失量80%以上,育秧期MT、ST占比不到2%,HT达4.2%。【结论】在不同种植方式下,间歇灌溉方式会提高双季稻产量和N2O排放,但会降低NH3挥发,从早、晚稻生育阶段来看,N2O损失主要发生在生育前期和后期,NH3挥发损失主要发生在生育前中期,且育秧期NH3挥发和N2O排放占比较低,DS在显著降低产量的同时带来了更高的N2O排放和NH3挥发。

[Objective]To investigate the effect of the methods of planting and irrigation on water use efficiency and gaseous loss of nitrogen during the whole growing stage of double season rice.[Methods]Taking the double season rice field as the research object,a field experiment was carried out in the research base of Jiangxi Provincial Irrigation Experiment Centre Station and this experiment was set up by four planting methods and two irrigation methods.The four panting methods are namely by hand-planting(HT),mechanical transplanting(MT),seedling throwing(ST)and direct seeding(DS),and two irrigation methods are namely by flooding irrigation(FI)and intermittent irrigation(II),and to analyze the effects of different methods of planting and irrigation on the water use efficiency during the whole growing stage and as well as on the volatilization of NH 3 and the emissions of N 2O in the seedling stage and home stage of the double season rice,and to put forward the main periods of the volatilization of NH 3 and the emissions of N 2O.[Results](1)Compared with traditional flooding irrigation,the rice yield was increased slightly under the intermittent irrigation,and there were appeared significantly different in yield among the different planting methods,and HT was the highest and DS was the lowest.(2)The N 2O emission of intermittent irrigation was increased by 7.9%~16.4%than the flooding irrigation under the same planting method,and N 2O loss of early rice was showed by DS>MT>HT>ST and late rice was by DS>HT>MT>ST,and the N 2O emission of double cropping rice were mainly occurred at tillering stage,jointing-booting stage,and ripening stage,and their N 2O loss accounted for more than 70%,however MT and ST were accounted for less than 1.5%in the seedling stage,and HT was 6.4%.(3)The volatility loss of NH 3 of flooding irrigation was increased by 3.0%to 30.8%than the intermittent irrigation in the whole growing stage of early rice and late rice under same planting method,DS was significantly increased for NH 3 volatility loss(P<0.05)than the transplanting rice under the same irrigation method,and there was no significant difference among HT,MT,and ST,and the peak of NH 3 volatility was appeared within 3 d after fertilization,and mainly occurred in the seedling,tillering,and pulling and gestation periods,and their NH 3 volatility loss accounted for more than 70%,however MT and ST were accounted for less than 2%in the seedling stage,and HT was 4.2%.[Conclusion]The intermittent irrigation method could be increased the yield and N 2O emission of double cropping rice under different cropping methods,but it also could be reduced the NH 3 volatilization.From the perspective of the early and late rice in the whole growing stages,N 2O losses was mainly occurred in the early and late stages,and NH 3 volatilization losses mainly occurred in the early to middle of fertility,and the proportion of NH 3 volatilization and N 2O emission was relative low during the seedling stage,and the DS brought about higher N 2O emission and NH 3 volatilization with a significant reduction in the yield.