氢醌和双氰胺对种稻土壤N_2O和CH_4排放的影响

Effect of hydroquinone and dicyandiamide on N 2O and CH 4 emissions from lowland rice soil.

通过盆栽试验，研究了脲酶抑制剂氢醌（ＨＱ）、硝化抑制剂双氰胺（ＤＣＤ）及二者的组合（ＨＱ＋ＤＣＤ）对种稻土壤Ｎ２Ｏ和ＣＨ４排放的影响．结果表明，在未施麦秸粉时，所有施抑制剂的处理均较单施尿素的能显著减少水稻生长期供试土壤Ｎ２Ｏ和ＣＨ４的排放．特别是ＨＱ＋ＤＣＤ处理，其Ｎ２Ｏ和ＣＨ４排放总量分别约为对照的１／３和１／２．而在施麦秸粉后，该处理的Ｎ２Ｏ排放总量为对照的１／２，但ＣＨ４排放总量却较少差别．不论是Ｎ２Ｏ还是ＣＨ４的排放总量，施麦秸粉的都比未施的高出１倍和更多．因此，单从土壤源温室气体排放的角度看，将未腐熟的有机物料与尿素共施，并不是一种适宜的施肥制度．供试土壤的Ｎ２Ｏ排放通量，与水稻植株的ＮＯ－３Ｎ含量和土表水层中的矿质Ｎ量分别呈显著的指数正相关和线性正相关；ＣＨ４的排放通量则与水稻植株的生长量和土表水层中的矿质Ｎ量呈显著的线性负相关．在Ｎ２Ｏ与ＣＨ４的排放间，未施麦秸粉时存在着定量的相互消长关系；施麦秸粉后，虽同样存在所述关系，但难以定量化．

Through pot experiments, this paper studied the effect of urease inhibitor hydroquinone (HQ), nitrification inhibitor dicyandiamide (DCD) and their combination (HQ+DCD) on the N 2O and CH 4 emissions from a lowland rice soil. The results show that with no wheat straw powder amended, all treatments with inhibitors significantly reduced the N 2O and CH 4 emissions during rice growth, as compared with the treatment only urea applied. Especially for treatment HQ+DCD, its total amount of N 2O and of CH 4 emission was about 1/3 and 1/2 of the control, respectively; while with wheat straw powder amended, the total N 2O emission of this treatment was 1/2 of the control, but that of CH 4 emission had less difference. Wheat straw powder amendment induced one times and more emissions of N 2O and CH 4 than no its application, and hence, even only from the standpoint of diminishing soil source greenhouse gases emission, applying unmatured composted organic materials with urea is an inappropriate fertilization system. The N 2O flux from this soil had a significant positive exponential relationship with the NO - 3 N content of rice plant and a significant positive linear relationship with the mineral N content in soil surface waterlayer, while CH 4 flux had a significant negative linear relationship both with the growth rate of rice plant and with the mineral N content in soil surface waterlayer. There existed a quantitative trade off between N 2O and CH 4 emission in case of no wheat straw powder incorporated, while with its amendment, the trade off still existed, but hard to quantify.