Nitrogen leaching and phosphorus accumulation in a perennial pasture after composted goat manure was topdressed and incorporated in the Three Gorges region
Nitrogen leaching and phosphorus accumulation in a perennial pasture after composted goat manure was topdressed and incorporated in the Three Gorges region
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DOI：
10.1007/s11368-012-0501-5
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发表时间：
2012-03
影响因子：
3.6
通讯作者：
Yanjun Guo;Guangdi D. Li
中科院分区：
文献类型：
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作者：
Yanjun Guo;Guangdi D. Li
目的堆肥施肥不当，可能增加养分淋溶和磷积累的风险，导致水体富营养化，威胁河流生态安全。本研究以三峡地区某多年生牧草为研究对象，研究了羊舍堆肥对牧草产量、土壤硝态氮淋溶和磷积累的影响。材料和方法堆肥羊粪在行与行之间0-20 cm的土壤深度进行手工追肥或用锄头掩埋，以4种施肥量（15、22.5、30和37.5 Mg DM ha - 1）和不施用堆肥粪肥的未修改对照。2005年7月、9月、11月和2006年1月、4月分5次施用堆肥，每次施用指定量的20%。采用土壤-树脂-岩心组合浸出-培养试验，测定了土壤中NO3-N的浸出量。结果与讨论土壤全氮、全磷浓度随堆肥施肥量的增加而增加。土壤NO3-N和从土壤中浸出的NO3-N随季节变化而变化。施肥15、22.5、30和37.5 mg ha - 1时，土壤有效磷分别达到92、132、225和261 mg kg - 1，追肥处理的有效磷分别达到39、78、86和132 mg kg - 1，表明土壤有效磷随肥料用量的增加而积累。随着堆肥施肥量的增加，牧草产量增加。在追肥处理中，施用37.5 Mg ha−1堆肥肥时牧草产量最高。相比之下，在22.5 Mg ha−1施肥时，牧场产量最高，进一步增加堆肥量会降低牧场产量。结论过量施用羊粪显著增加了土壤硝态氮淋溶和磷积累的风险。综上所述，羊粪堆肥的施肥量应低于22.5 Mg ha - 1，以减少硝态氮淋溶和磷积累，同时保持牧草高产。为了满足草场的生长需要，建议分块施用，从而减少NO3-N淋溶和土壤P积累，这在三峡地区具有重要意义。
PurposeImproper utilization of composted manure might increase risk of nutrients leaching and phosphorus (P) accumulation, hence causing eutrophication and threatening the ecological safety of river. In the current study, composted manure from a goat feedlot was applied to a perennial pasture in the Three Gorges region to evaluate its effects on pasture yield, NO3–N leaching, and phosphorus accumulation in soil.Materials and methodsComposted goat manure was either topdressed by hand or incorporated by hoe in the 0–20 cm soil depth between rows at four application rates (15, 22.5, 30, and 37.5 Mg DM ha−1) and an unamended control without application of composted manure. The composted manure was applied five times, with 20 % of the designated amount each, in July, September, and November 2005 and January and April 2006. A combination leaching–incubation experiment (soil-resin-core) was conducted to measure the amount of NO3–N leached from soils.Results and discussionSoil total nitrogen and P concentrations increased as amount of composted manure applied was increased. Soil NO3–N and NO3–N leached from soil varied across seasons. Soil available P reached 92, 132, 225, and 261 mg kg−1when 15, 22.5, 30, and 37.5 Mg ha−1of composted manure was incorporated, respectively, and soil available P reached 39, 78, 86, and 132 mg kg−1for corresponding treatments for topdressed treatment, indicating soil available P accumulated with increased manure applied. Pasture yield increased as application rate of composted manure increased. For the topdressed treatments, the highest pasture yields were obtained at 37.5 Mg ha−1of composted manure applied. As a comparison, the highest pasture yields was obtained at 22.5 Mg ha−1when composted manure was incorporated, further increase of composted manure decreased the pasture yields.ConclusionsExcess use of composted goat manure significantly increased the risk of soil NO3–N leaching and P accumulation. It is suggested that the composted goat manure should be incorporated at rate of less than 22.5 Mg ha−1to minimize NO3–N leaching and P accumulation while maintaining high pasture production. The split application is also recommended to meet the growth requirement of pastures, hence less NO3–N leaching and soil P accumulation, which is of importance in the Three Gorges region.