氮肥对宁夏地区水稻田N_2O排放的影响

为了摸清不同氮肥水平下水稻田N2O的排放规律,利用静态箱—气相色谱法,对宁夏地区水稻田N2O的排放进行田间原位观测。结果表明,氮肥的施入显著促进水稻田N2O的排放,不同氮肥水平间N2O的排放存在显著差异。在整个观测期内,不施氮肥处理无明显的N2O排放高峰,而施氮处理在水稻生长后期进行排水晒田时出现1个比较明显的峰值,其余时间N2O排放通量无明显变化趋势。施氮处理N2O的排放主要集中在水稻灌浆期,不施氮处理其排放主要集中于水稻返青期、拔节期、灌浆期和成熟后。随着施氮量的增加,水稻田以N2O形式损失的氮量减少。分析各处理水稻田间N2O的全球增温潜势(GWP),得出随着施氮量的增加其潜势逐步提高,对环境的影响不容忽视。

Effect of Nitrogen Fertilizer on the Emission of N2O from Paddy Field in Ningxia, China

In order to study the variation law of N₂O emission under different nitrogen fertilization in the rice paddy of Ningxia area, a field experiment was conducted, and in situ observation with static chamber and gas chromatograph was carried out. The results showed that, the emission of N₂O from rice paddy could be promoted by the nitrogen fertilization, and there were significant differences of the emission of N₂O between rice paddy with different levels of nitrogen fertilization. During the whole observation period, Only one emission peak of N₂O in the rice paddy treated with different nitrogen fertilization was detected at the late stage of rice grain filling, But the emissions of N₂O had no peak in the control treatment and which was mainly at the green, jointing, grain filling and maturity stage. With the increasing of nitrogen, the loss of nitrogen in the form of N₂O reduced. The N₂O global warming potential (GWP) was increased gradually with the increase of nitrogen amount, and its impact on the environment can not be ignored.