【摘要】 以宁夏荒漠草原优势植物赖草(Leymus secalinus)、胡枝子(Lespedeza bicolor)及二者混合物为研究对象,采用分解袋法研究了不同处理间植物枯落物营养元素残留率变化特征,旨在揭示荒漠草原优势植物枯落物分解过程中营养元素变化规律。结果显示,(1)随着分解时间变化,P在3种处理植物枯落物中均呈"释放-富集-释放"的规律;K在胡枝子和混合枯落物中呈"释放-富集-释放"的规律,而在赖草枯落物中则仅表现为释放现象;N在赖草和胡枝子枯落物中呈"释放-富集-释放"的规律,而在混合枯落物中则仅表现为释放现象。(2)经过640d分解,P和K残留率表现为胡枝子枯落物>赖草枯落物>混合枯落物,N残留率表现为赖草枯落物>混合枯落物>胡枝子枯落物。(3)经过640 d分解,植物枯落物P、K和N在3种处理间整体上呈净释放状态。研究表明,宁夏荒漠草原植物枯落物营养元素变化特征与植物种的差异性密切相关;混合植物枯落物P和K释放率高于单一种植物枯落物,而N释放率表现为胡枝子枯落物高于赖草及二者混合枯落物。更多还原

【Abstract】 An investigation on nutrient elemental residual rate of plant litter of dominant Leymus secalinus, Lespedeza bicolor and their mixture was carried on by the method of litterbag sampling. The objective of the present study is to probe into the changes of plant nutrient element during litter decomposition process in desertified steppe of Ningxia. The results showed:(1) As the decomposition time changed, there was an alternatives of "release-accumulation-release" course of plant P in three litter treatments.There was an alternative of "release-accumulation-release" course of plant K in L. bicolor and their mixture litter, whereas there was a "release" course of plant K in L. secalinus litter. There was an alternative of "release-accumulation-release" course of plant N in L.bicolor and L. secalinus litter, whereas there was a "release" course of plant N in in their mixture litter.(2) At the sampling time of 640 days, the residual rate of plant litter P and K was found to follow an order of L. bicolor>L. secalinus>mixture, whereas plant litter N was found to follow an order of L. secalinus>mixture>L. bicolor. And(3) during the whole decomposition process, plant litter P, K and N were found to indicate a "release" course in three treatments. It was concluded that the changes of nutrient element was closely related to litter differences in terms of plant species. The release rate of plant P and K in mixture litter was suggested to be greater compared with single plant litter, whereas that of plant N in L. bicolor litter was suggested to be greater compared with L.secalinus and their mixture litter.更多还原