【摘要】 为了解畜粪的分解特征及对半干旱典型草原养分循环的影响,于2008年6月~2009年10月采用人为控制的野外实验,研究了羊粪和牛粪对内蒙古典型草原草地的输入量,分解过程中的重量损失、有机物和氮(N)、磷(P)浓度变化.结果表明,羊粪和牛粪的年输入量分别约为(17.8±13.8)kg hm-2和(365.6±495.9)kg hm-2.分解450 d后,残留粪样中有机物浓度较鲜粪减少约14.46%(羊粪)和48.78%(牛粪),即羊粪的分解速率较牛粪显著缓慢,2种粪的残留粪块在草地中堆置时间至少可达2个生长季以上.两种粪中,N素以有机态为主,矿化和释放速度均较慢;P素以无机态为主,释放速度较快;春季冻融变化可以显著促进两种粪中N和P的矿化速率;实验结束时,残留粪样中的全N浓度较鲜粪分别降低了25.89%(羊粪)和16.07%(牛粪),全P分别降低了30.73%和27.21%.埋入地下处理,可以消除风蚀对羊粪块失重的影响,使残留粪样保持较高湿度,促进有机质分解,并改变淋溶作用对粪块中养分含量的影响;但对牛粪分解无明显影响.从研究结果可以看出,家畜粪在半干旱草地环境中分解较慢,堆积过程中对草地的养分循环有重要影响.更多还原

【Abstract】 The inputs and decomposition of sheep and cattle dung at two grazed grasslands in Inner Mongolia steppe were monitored to understand effect of livestock dung decomposition on the nutrient cycling of semiarid grassland ecosystem.The inputs of sheep and cattle dung were about(17.8 ± 13.8) and(365.6 ± 495.9) kg hm-2 a-1,respectively.After 450 days decaying,the concentration of organic matter in residual dung decreased by 14.46%(sheep dung) and 48.78%(cattle dung),respectively compared to the fresh dung,suggesting that the decomposing rate of sheep dung was slower than that of cattle dung,and the dungs could last at least two growing seasons on the grassland floor.Most of the nitrogen was organic with relatively lower mineralization rate,while phosphorus was mostly inorganic and released faster.Freezing-thawing cycle in spring could remarkably promote the rates of N,P mineralization.Compared to fresh dung,the concentration of total N in residual dung decreased by 25.89%(sheep dung) and 16.07%(cattle dung),respectively,and the concentration of total P decreased by 30.73% and 27.21%,respectively at the end of the experiment.Dung was buried in 10 cm soil layer and had relatively higher water content because of excluding the effect of wind-erosion on mass loss of residual sheep dung,which resulted in a quicker decaying rate of organic matter,and altered the impacts of eluviations on the nutrient content in the residual dung,but such effects were not significant on cattle dung.The results suggested that water environment affect the decaying rate of livestock dung in semiarid grassland,and their deposition seriously influence the nutrient cycling of the grassland ecosystem.更多还原