The interactive effects of soil texture and type of N fertility (i.e., manure vs. commercial N fertilizer) on N2O and CH4 emissions have not been well established. Th is study was conducted to assess the impact of soil type and N fertility on greenhouse gas fluxes (N2O, CH4, and CO2) from the soil surface. The soils used were a sandy loam (789 g kg−1 sand and 138 g kg−1 clay) and a clay soil (216 g kg−1 sand, and 415 g kg−1 clay). Chamber experiments were conducted using plastic buckets as the experimental units. The treatments applied to each soil type were: (i) control (no added N), (ii) urea-ammonium nitrate (UAN), and (iii) liquid swine manure slurry. Greenhouse gas fluxes were measured over 8 weeks. Within the UAN and swine manure treatments both N2O and CH4 emissions were greater in the sandy loam than in the clay soil. In the sandy loam soil N2O emissions were significantly different among all N treatments, but in the clay soil only the manure treatment had significantly higher N2O emissions. It is thought that the major differences between the two soils controlling both N2O and CH4 emissions were cation exchange capacity (CEC) and percent water-filled pore space (%WFPS). We speculate that the higher CEC in the clay soil reduced N availability through increased adsorption of NH4+ compared to the sandy loam soil. In addition the higher average %WFPS in the sandy loam may have favored higher denitrification and CH4 production than in the clay soil.
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机译：土壤质地和氮肥类型（即肥料与商业氮肥）对N2O和CH4排放的交互作用尚未得到很好的确定。该研究旨在评估土壤类型和氮肥对土壤表层温室气体通量（N2O，CH4和CO2）的影响。使用的土壤是砂壤土（789 g kg-1沙子和138 g kg-1粘土）和粘土（216 g kg-1沙子和415 g kg-1粘土）。使用塑料桶作为实验单元进行腔室实验。适用于每种土壤类型的处理方法是：（i）对照（不添加N），（ii）尿素-硝酸铵（UAN）和（iii）猪粪肥液。在8周内测量了温室气体通量。在UAN和猪粪处理中，砂壤土中N2O和CH4的排放均比黏土中的大。在沙壤土中，所有氮处理之间的N2O排放量均存在显着差异，但在粘土土壤中，仅粪便处理的N2O排放量显着较高。可以认为，控制N2O和CH4排放的两种土壤之间的主要差异是阳离子交换容量（CEC）和含水孔隙率百分比（％WFPS）。我们推测，与砂壤土相比，粘土中较高的CEC通过增加NH4 +的吸附来降低N的有效性。此外，与壤土相比，沙壤土中较高的平均％WFPS可能有助于较高的反硝化作用和CH4的产生。
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