猪粪固体自然堆放方式下含氮气体排放规律及其影响因素研究

Nitrogenous Gas Emissions from Solid Swine Manure Under Natural Composting Conditions

针对我国畜禽固体废弃物自然堆放管理过程中含氮气体排放欠缺系统研究、排放规律尚不清晰的现状,以长江流域生猪固体废弃物典型自然堆放方式为例,采用静态箱-气相色谱法、化学发光法、磷酸甘油溶液吸收法对猪粪固体堆放下N2O、NOx和NH33种主要含氮气体排放进行了一个堆肥周期的系统观测,深入研究了猪粪固体堆放管理方式下3种含氮气体排放规律及其影响因素。一个堆放周期的试验结果表明:在固体贮存堆体最初含水量较多的情况下,NH3前期排放较多,后期排放比较少,受堆体氨态氮浓度影响较大。N2O和NOx的排放规律基本相同,都呈现前期排放量较小,后期排放增多的态势,这与降雨导致的酸性环境加剧硝化反硝化作用有关。堆体表面与堆体内部剖面N2O的排放趋势基本相同,而堆体下部土壤剖面的N2O受堆体影响较小。

In China growing livestock industries are arousing public concerns over the environmental quality, especially atmospheric environ- ment. In this study, we collected emission data of three nitrogenous gases, nitrous oxide （N20）, nitrogen oxides （NOx） and ammonia （NH3）, from naturally composted swine manure piles in Changsha, Hunan, China, during one composting period（53 days）. A statistic chamber was employed for sampling gases and gas-chromatography for quantifying gas concentrations. The daily emission rate of NH3 was the highest at the beginning of the composting, then decreased rapidly during the following 14 days, and kept relatively low during the rest time of the ex- periment; The emissions of N20 and NOx were initially low but gradually increased. The emissions of nitrogenous gases from the surface and inside of the compost piles showed roughly similar patterns. Since no ammonium or nitrate in the compost piles were measured at the begin- ning, it could be hypothesized that the initial high NH3 emissions could result only from urea or dissolved NH3 in the original manure while emissions of N20 or NOx could be related to increased moisture or nitrate at the late stage of the composting process. Further studies are needed to prove or disprove the hypotheses.