氮肥对潮棕壤稻田N_2O排放和土壤无机氮素的影响

Effects of N fertilization on the N_2O emissions and soil nitrogen in aquic brown soil

采用静态箱(暗箱)-气相色谱法对潮棕壤不同施肥处理的稻田N2O排放进行了原位观测,同时测定了整个生长季0cm^10cm、10cm^20cm耕层土壤中NO3--N、NH4+-N含量的动态变化。结果表明:植物—土壤系统为大气N2O的源。不同耕层土壤NO3--N含量在整个生长季的变化呈“两头高中间低”的形式:在水稻生长前期和收割前后较高,在生长中期含量很低;而NH4+-N含量在水稻成熟以前较高,进入成熟期以后含量急剧降低。氮肥施用可增加稻田N2O排放的总量和耕层土壤(0 cm^20cm)NH4+-N含量;对NO3--N含量则无明显影响。图3,参16。

A field experiment was conducted to evaluated N2O fluxes from rice paddy fields using static chamber-gas chromatographic techniques. At the same time, the contents of NO3^- - N, NH4^＋ - N in the different depth soil （0cm - 10 cm, 10cm - 20 cm） were measured respectively.The results were as follows： in the growing season, the soil-plant system is the source of atmospheric N2O,The variation of NO3^- - N eontents in different depth appear very regular： it is higher in early rice paddy growing stage, harvest period , and lower in middle rice paddy growing stage.The NH4^＋ - N contents is higher before rice paddy mature , but it reduced sharply after rice paddy matured.Application of nitrogen fertilization enhanced N2O total fluxes from paddy rice and NH4^＋ - N contents in soils, but its effect on NO3^- - N contents （0 cm - 20cm） in soil is not remarkable.