Waterhouse Hannah, Wade Jordon, Horwath William R, Burger Martin
J Environ Qual. 2017 Sep;46(5):1123-1130. doi: 10.2134/jeq2017.01.0033.
Synthetic nitrogen (N) fertilizer formulations vary in their effects as substrates on nitrous oxide (NO) emissions. Mitigation of NO emissions can potentially be achieved through appropriate choice of N fertilizer sources combined with stabilizers. The effects of three N fertilizers and urease and nitrification inhibitors on NO emissions, crop N uptake, and yields were determined in a furrow-irrigated corn ( L.) system in Reiff loam soil in the Sacramento Valley of California for one growing season. Aqua ammonia (Aq. NH), urea ammonium nitrate (UAN), and calcium nitrate were sidedressed at the rate of 202 kg N ha. The control treatment received only starter fertilizer (20 kg N ha). Total seasonal emissions were in the order Aq. NH > UAN > calcium nitrate = control with 1.38, 0.97, 0.35, and 0.27 kg NO-N ha, respectively. A novel, positively charged form of dicyandiamide, KAS-771G77 (G77), was combined with Aq. NH and UAN to test the effectiveness of this nitrification inhibitor in reducing NO emissions. When combined with Aq. NH, G77 did not reduce the emissions, but G77 significantly lowered them in the UAN treatment. A similar reduction of NO emissions in the UAN treatment was achieved with the urease and nitrification inhibitor AgrotainPlus. Yields and N use efficiency did not differ among the fertilized treatments. Ammoniacal fertilizers had higher NO emissions than nitrate-based fertilizers, which could imply nitrification pathways as a source of NO emissions. The use of G77 or AgrotainPlus, when applied with UAN, was an effective NO mitigation practice.
合成氮肥配方作为底物对一氧化二氮（N₂O）排放的影响各不相同。通过适当选择氮肥来源并结合稳定剂，有可能减少N₂O排放。在加利福尼亚州萨克拉门托山谷的赖夫壤土中，对一种沟灌玉米（L.）系统进行了一个生长季的试验，测定了三种氮肥以及脲酶和硝化抑制剂对N₂O排放、作物氮吸收和产量的影响。以202千克氮/公顷的用量侧施液氨（Aq. NH₃）、硝酸脲铵（UAN）和硝酸钙。对照处理仅施用基肥（20千克氮/公顷）。季节性总排放量依次为Aq. NH₃＞UAN＞硝酸钙 = 对照，分别为1.38、0.97、0.35和0.27千克N₂O-N/公顷。一种新型带正电荷的双氰胺形式KAS-771G77（G77）与Aq. NH₃和UAN混合，以测试这种硝化抑制剂在减少N₂O排放方面的有效性。与Aq. NH₃混合时，G77没有减少排放，但在UAN处理中G77显著降低了排放。使用脲酶和硝化抑制剂AgrotainPlus也使UAN处理中的N₂O排放有类似减少。施肥处理间的产量和氮利用效率没有差异。铵态氮肥的N₂O排放高于硝态氮肥，这可能意味着硝化途径是N₂O排放源。与UAN一起使用时，G77或AgrotainPlus是有效的N₂O减排措施。
