Ammonia volatilization from a paddy field following applications of urea: Rice plants are both an absorber and an emitter for atmospheric ammonia
Ammonia volatilization from a paddy field following applications of urea: Rice plants are both an absorber and an emitter for atmospheric ammonia
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DOI：
10.1016/j.scitotenv.2007.10.037
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发表时间：
2008-02-15
影响因子：
9.8
通讯作者：
Yagi, Kazuyuki
中科院分区：
文献类型：
--
作者：
Hayashi, Kentaro;Nishimura, Seiichi;Yagi, Kazuyuki
测定了稻田施用尿素后氨（NH3）的挥发。灰色低地土壤的pH值（H2O）为5.7的两个蒸渗仪用于实验。尿素的施用量为50 kg N ha（-1），通过掺入作为基础施肥（BF），并以30和10 kg N ha（-1）的施用量通过追肥分别作为第一次（SF 1）和第二次（SF 2）补充施肥。每个蒸渗仪安装两个风洞后，BF;一个是移植水稻植物（PR情节），另一个是没有水稻植物（NR情节）。在BF后的PR图中观察到弱挥发。相比之下，SF 1后PR地块观察到强烈的挥发，最大通量为150 g N ha（-1）h（-1）;然而，SF 2后几乎没有观察到挥发。NH3挥发损失量分别占尿素施用量的2.1%、20.9%、0.5%和8.2%，其中NH3挥发损失仅占尿素净排放量的2.1%、20.9%、0.5%和8.2%。利用膜模型估算了NR小区稻田水面NH3挥发通量（F-vol），并进行了验证。在确认良好的相关性后，应用膜模型估计PR图处的F-vol。水稻植株的NH3交换通量（F-ric）通过从观测的净NH3通量中减去F-vol得到。推导的F-ric表明，水稻植株排放NH_3显着后SF_1时，相对较高的比例施加尿素，虽然他们吸收大气中的NH_3在其他时期。总之，水稻植物本质上是大气NH3的吸收者，然而，在氨态氮的过量营养下，它们变成NH3的排放者。(c)2007 Elsevier B. V.保留所有权利。
Ammonia (NH3) volatilization from a paddy field following applications of urea was measured. Two lysimeters of Gray Lowland soil with a pH (H2O) of 5.7 were used for the experiment. Urea was applied at a rate of 50 kg N ha(-1) by incorporation as the basal fertilization (BF) and at rates of 30 and 10 kg N ha(-1) by top-dressing as the first (SF1) and second (SF2) supplemental fertilizations, respectively. Two wind tunnels per lysimeter were installed just after BF; one was transplanted with rice plants (PR plot), and the other was without rice plants (NR plot). Weak volatilization was observed at the PR plots after BF. By contrast, strong volatilization was observed at the PR plots after SF1 with a maximum flux of 150 g N ha(-1) h(-1); however, almost no volatilization was observed after SF2. The NH3 volatilization loss accounted for 2.1%, 20.9%, 0.5%, and 8.2% of the applied urea at each application, BF, SF1, SF2, and the total application, respectively, for which only the net fluxes as volatilization were accumulated. The NH3 volatilization fluxes from the paddy water surface (F-vol) at the NR plots were estimated using a film model for its verification. After confirmation of good correlation, the film model was applied to estimate F-vol at the PR plots. The NH3 exchange fluxes by rice plants (F-ric) were obtained by subtracting F-vol from the observed net NH3 flux. The derived F-ric showed that the rice plants emitted NH3 remarkably just after SF1 when a relatively high rate of urea was applied, although they absorbed atmospheric NH3 in the other periods. in conclusion, rice plants are essentially an absorber of atmospheric NH3; however, they turn into an emitter of NH3 under excess nutrition of ammoniacal nitrogen. (c) 2007 Elsevier B.V. All rights reserved.