Nitrogen leaching and phosphorus accumulation in a perennial pasture after composted goat manure was topdressed and incorporated in the Three Gorges region

作者：Guo Yanjun^*; Li Guangdi

来源：Journal of Soils and Sediments, 2012, 12(5): 674-682.

DOI：10.1007/s11368-012-0501-5

• Environmental safety
• Feedlot
• Pasture yields
• Perennial pasture

Improper 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.
Composted 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.
Soil 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(-1) when 15, 22.5, 30, and 37.5 Mg ha(-1) of composted manure was incorporated, respectively, and soil available P reached 39, 78, 86, and 132 mg kg(-1) for 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(-1) of composted manure applied. As a comparison, the highest pasture yields was obtained at 22.5 Mg ha(-1) when composted manure was incorporated, further increase of composted manure decreased the pasture yields.
Excess 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(-1) to 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.

• 出版日期2012-5
• 单位西南大学