羊粪归还对荒漠草原表层土壤碳氮的影响  

Effect of Sheep Dung Return on Surface Soil Organic Carbon and Total Nitrogen Contents in Deserted Grassland

作　　者：王兴[1] 宋乃平[1,2] 杨新国[1] 肖绪培[2] 杨明秀[1] 

机构地区：[1]宁夏大学西北土地退化与生态恢复国家重点实验室培育基地,宁夏银川750021 [2]宁夏大学资源环境学院,宁夏银川750021

出　　处：《水土保持通报》2013年第5期6-10,共5页Bulletin of Soil and Water Conservation

基　　金：国家重点基础研究发展计划前期研究专项"荒漠草原农牧系统稳定性与维持机理研究"(2012CB723206);国家科技支撑计划课题"荒漠草原区农牧复合生态系统构建与可持续利用技术集成试验与示范"(2011BAC07B03)

摘　　要：以宁夏回族自治区盐池县的荒漠草原围栏放牧草地为研究对象，按自然形成的地表羊粪积累量梯度，设置了6个梯度序列控制样地（1．41～1581．68g／m2），分析羊粪量与表层O-5cm土壤有机碳、全氮含量的对应关系。同时，以羊粪量对数lnf为自变量x，与表层土壤有机碳，全氮含量构建回归模型。结果表明：（1）地表羊粪量在较低水平时，表层O-5cm土壤有机碳含量未发生显著变化；羊粪量在较高水平时，土壤有机碳含量跃变特征明显。（2）表层O-5cm土壤全氮含量在羊粪积累量较少时，开始出现显著的增长，跃变特征明显。（3）随着地表羊粪量的增加，土壤C／N比分别发生转折性变化，整体呈先降低后上升的趋势。初步研究认为，自由放牧条件下，羊粪归还是影响荒漠草原表层土壤有机碳和全氮含量的重要过程。地表羊粪积累量在较低水平时，羊粪对土壤全氮归还作用开始显现，但是，只有当羊粪积累量在较高水平时，对土壤有机碳及全氮的净归还作用才会显著增强。受土壤有机碳和全氮归还作用的交互影响，土壤碳氮比呈现出先下降后上升的变化趋势。The relationships between sheep dung quantity and the organic carbon and total nitrogen contents within 5 cm of surface soil were studied by setting up sequential plots of six grades（1.411 581.68 g/m2） according to sheep dung quantity grade formed naturally in Ningxia Hui Autonomous Region deserted steppe ecosystem. Models were then established for logarithmic sheep dung quantity, as an independent variable, and the surface soil organic carbon and total nitrogen contents, as dependent variables. Results showed the surface soil organic carbon content did not change significantly at a low level of sheep dung quantity, but changed obviously at a high level. The surface soil total nitrogen content changed obviously at a low level of sheep dung quantity. Ratio of soil carbon to soil nitrogen increased firstly and then decreased with the in creased sheep dung quantity. Preliminary research concluded that sheep dung nutrients return is a very im portant process affecting soil organic carbon and total nitrogen contents under free grazing conditions in the deserted steppe ecosystem. The effect of the returned sheep dung quantity on soil total nitrogen began to ap pear when accumulated sheep dung quantity was at a low lever, but the net returns of soil organic carbon and soil total nitrogen contents were significantly enhanced at a higher level. The ratio of soil carbon to nitrogen showed a complex trend because of the interactive effect of the returned soil organic carbon and total nitrogen.

关 键 词：羊粪积累量 养分归还 土壤有机碳 土壤全氮 荒漠草原 

分 类 号：S812.8[农业科学—草业科学]