Ammonia volatilization, a primary N loss pathway from rice (Oryza sativa L.) production systems, leads to a reduction in N use efficiency and environmental problems. Ammonia volatilization has not been studied in water‐seeded rice systems or where aqueous NH₃ is the primary fertilizer N source. Our objective was to quantify NH₃ volatilization from preplant aqueous NH₃ and compare it with drilled or broadcast urea. In addition, NH₃ volatilization from a topdress N application applied midseason was quantified. This was accomplished with 10 field experiments representing a range of soil types. Preplant N treatments were a zero‐N control, injected aqueous NH₃, broadcast urea, and drilled urea all applied at the farmer application rate to a dry soil. For the topdress experiment, the treatments were a zero‐N control and urea or (NH₄)₂SO₄ applied at 34 kg N ha⁻¹. Ammonia volatilization was measured up to 3 and 1 wk after the preplant and topdress N was applied, respectively, using a semi‐open static chamber. Losses due to NH₃ volatilization from preplant broadcast urea were significantly higher than from the other other treatments but accounted for <2% of applied N. Losses from aqueous NH₃ and banded urea were lower but were significantly greater than from the control. The losses occurred in the first week after flooding. When N was topdressed, 1.5 and 2.6% of applied N were lost via volatilization from urea and (NH₄)₂SO₄, respectively.

中文翻译：

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肥料的来源和位置影响水培稻米系统中氨气的挥发损失

氨挥发是水稻（水稻）生产系统中氮的主要损失途径，导致氮利用效率和环境问题的降低。氨水挥发在水稻种植的水稻系统中或NH ₃水溶液是氮肥的主要来源时尚未进行研究。我们的目标是定量从种植前的NH ₃水溶液中NH ₃挥发，并将其与钻孔或撒播的尿素进行比较。此外，定量了季中施用的Topdress N施肥中的NH ₃挥发量。这是通过代表各种土壤类型的10个田间试验完成的。种植前的氮处理为零氮对照，注入NH ₃水溶液，撒播尿素和钻井尿素都以农民的施用量施用到干燥的土壤上。对于追肥试验，处理为零氮控制，并以34 kg N ha ^-1施用尿素或（NH ₄）₂ SO ₄。使用半开放式静态腔室分别在施用了种植前喷剂和氮肥后，分别测量了3周和1周时的氨挥发。种植前撒播的尿素引起的NH ₃挥发损失明显高于其他处理，但占施用氮的<2％。NH ₃水溶液的损失和带状尿素比对照低，但显着大于对照。损失发生在洪水后的第一周。追施氮肥时，尿素和（NH ₄）₂ SO _4的挥发分别损失了1.5％和2.6％的氮肥。