Barton L, Schipper L A
Landcare Research, Hamilton, New Zealand.
J Environ Qual. 2001 Nov-Dec;30(6):1881-7. doi: 10.2134/jeq2001.1881.
Animal slurries and effluents are commonly applied to soil as a source of organic N fertilizer. By increasing inorganic N, applying animal effluents may also increase soil nitrous oxide (N2O) emissions. Our objectives were to (i) determine if dairy farm effluent (DFE) irrigation increased short-term N2O emissions from a surface-drained peat soil and a freely drained mineral soil and (ii) see if this increase could be attributed to increased N availability, increased soil water content, or a combination of both factors. We measured short-term N2O emissions following DFE irrigation in spring and autumn, using closed chambers. Nitrous oxide emissions from DFE-irrigated soils (50 kg N ha(-1), 20-mm hydraulic loading) were compared with soils receiving inorganic nitrogen and water (50 kg N ha(-1), 20 mm), inorganic N only (50 kg N ha(-1)), water only (20 mm), and no treatment. Nitrous oxide emissions increased immediately following DFE irrigation to both soils, and were generally greater than emissions following the application of inorganic fertilizer with water. Increased N20 emissions following DFE irrigation coincided with increased soil water contents and mineral N and CO2 emissions. We suggest that DFE application increased N2O emissions more than inorganic N fertilizer by enhancing denitrification either by increasing C availability and/ or decreasing soil aeration following increased respiration. These findings suggest that the proportion of N applied to the soil and emitted as N2O may at times be greater for organic N fertilizers than inorganic N fertilizers, particularly if the organic N fertilizer contains sufficient available C to enhance denitrification.
动物粪便和污水通常作为有机氮肥施用于土壤。通过增加无机氮，施用动物污水也可能增加土壤一氧化二氮（N₂O）的排放量。我们的目标是：（i）确定奶牛场污水（DFE）灌溉是否会增加表层排水泥炭土和自由排水矿质土的短期N₂O排放量；（ii）查看这种增加是否可归因于氮有效性的提高、土壤含水量的增加或这两个因素的综合作用。我们在春季和秋季使用密闭箱测量了DFE灌溉后的短期N₂O排放量。将DFE灌溉土壤（50千克氮/公顷，20毫米水力负荷）的一氧化二氮排放量与接受无机氮和水（50千克氮/公顷，20毫米）、仅无机氮（50千克氮/公顷）、仅水（20毫米）以及未处理的土壤进行了比较。DFE灌溉后，两种土壤的一氧化二氮排放量立即增加，并且通常大于施用无机肥料和水后的排放量。DFE灌溉后N₂O排放量的增加与土壤含水量、矿质氮和二氧化碳排放量的增加同时出现。我们认为，DFE的施用通过增加碳的有效性和/或在呼吸作用增强后降低土壤通气性来促进反硝化作用，从而比无机氮肥更能增加N₂O的排放量。这些发现表明，对于有机氮肥而言，施用于土壤并以N₂O形式排放的氮的比例有时可能高于无机氮肥，特别是如果有机氮肥含有足够的有效碳来促进反硝化作用。
