Developing a management system of animal manure to reduce greenhouse gas emission and water contamination

研究在一个芦苇金丝雀草地上进行，在那里andiol占主导地位，与奶牛粪便施用。用能量平衡法估算的田间蒸散量与用标准鲍文比法估算的值吻合较好。采用条件采样法连续测定了温室气体和其他气体（N_2O、CO_2、CH_4、NH_3）的通量。结果表明，即使在积雪季节，大气与地面之间也存在着N_2O和CO_2气体的循环交换。通过测定氮同位素δ^<15>N在铵态氮、铵态氮、硝态氮、硝态氮、硝态氮中的天然丰度，发现施用有机肥后，nh3发生挥发和硝化，随后发生反硝化。因此，施肥后的N_2O气体排放可归因于硝化和反硝化两个过程。随着土壤温度的降低，硝化速率降低的幅度更大，积雪季节观测到的N_2O气体通量可能是由脱硝作用引起的。N_2O气体通量随土壤含水量的增加呈线性增加。这可能会导致降雨事件后N_2O气体通量的大幅增加。由于阴离子被andiol吸附明显，阴离子的吸附可能导致相对少量的阴离子输送到地下水中。草田全年的N_2O气体排放可能是由于andiol吸附NO_3^-离子的反硝化作用所致。我们估计，N_2O气体排放约占总氮用量的17%。在早春解冻期，土壤中水通量较大。由于土壤含水量影响N_2O气体排放，因此需要进一步研究土壤冻融与温室气体排放的关系。建立了二维完全耦合的水、溶质和热输运模型。在制定农田动物粪便施用管理办法时，应考虑动物粪便对水和大气环境的影响。少

The research was conducted at a reed canary grass field, where Andisol was predominant, applied with dairy cattle manure. Estimates of evapotranspiration in the field using an energy balance method were agreed well with those with the standard Bowen ratio method. The fluxes of greenhouse and other gases, N_2O, CO_2, CH_4, and NH_3, were continuously measured using the conditional sampling method. It was found that there were cyclic exchanges of N_2O and CO_2 gases between the atmosphere and the ground even in a snow accumulated season. By measuring the natural abundance of nitrogen isotopes, δ^<15>N, in ammonium-, NH_4^+-, and nitrate, NO_3^--, nitrogen, we found that just after the manure application the volatilization and nitrification of NH_3, immediately followed by denitrification, occurred. Thus, it was implied that the N_2O gas emission after the manure application was attributed to both the processes of nitrification and denitrification. As the rate of nitrification decreased w … More ith decreases in soil temperature, the N_2O gas flux observed during the snow accumulated season might be caused by denitification. We also found that the N_2O gas flux increased linearly with increases in soil water content. This might result in a large spike of N_2O gas flux occurred after rainfall events. As the adsorption of anions by the Andisol was evident, the anion adsorption might cause the relatively small amounts of anions transported to the groundwater. The year-round emission of N_2O gas from the grass field might be resulted from the denitrification of the NO_3^- ion adsorbed by Andisol. We evaluated that the N_2O gas emitted was approximately 17% of the total nitrogen applied. A large water flux in soil was observed during a thawing period in the early spring. Since soil water content affected the N_2O gas emission, further research is needed to understand the relationship between the freezing and thawing of soil and the emission of the greenhouse gases. A two-dimensional fully-coupled water, solute, and heat transport model was developed. We should consider the effect of animal manure on both water and atmospheric environments when we establish management practices for animal manure application to an agricultural field. Less