施用羊粪条件下人工草地土壤硝态氮淋失量研究

采用SRC（Soil-Resin-Core）装置，研究了三峡库区草畜配套体系中羊粪还田量与硝态氮淋失量的关系。研究结果表明，有机肥本身即可产生硝态氮在土壤中的累积，羊粪施肥量越高，土壤硝态氮累积量和全氮含量就越高。随着施肥次数的增加，全氮含量整体呈上升趋势，硝态氮含量因降雨、气温和牧草生长等因素的影响，存在明显的季节性。元月份土壤中的硝态氮含量显著高于其它季节。相关分析表明：土壤全氮和硝态氮含量影响20cm土层中硝态氮的淋失量，三者之间呈显著正相关关系；施肥提高了人工草地的产草量，但施肥量过高，草地产量下降，增加了氮素损失的可能性。在一定的产草量下，人工草地可容纳的羊粪量高于单位土地面积承载羊只所产生的羊粪量。说明在三峡库区发展集约化的种草养羊业，羊粪直接还田，从资源环境的角度分析是可行的。

Study of Nitrate Leaching from Artificial Grassland under Sheep Manure Application

With soil-resin-core equipment, correlation between sheep manure application and nitrate leaching amount under grassland-farming system in three gorges region was studied. Results showed that there had nitrate accumulation of organic fertilizer in soil. Nitrate accumulation and total soil nitrogen content increased with increasing manure application. Nitrate content in soil changed seasonally because of changing precipitation, temperature and grass growth and highest content was found in January. Total soil nitrogen content and nitrate content significantly influenced nitrate leaching amount from 20 cm depth soil, they had significant positive correlation. Manure application significantly increased grass yields while surplus application decreased yields and increased nitrate leaching possibility. Under certain grass yields, carrying capacity of sheep manure by pasture was higher than the manure produced from sheep breed on certain area of pasture. With manure returned to pasture, it is feasible to develop confinement rearing in three gorges region based on resources and environment.