宁南典型退耕模式对土壤有机碳固存的影响

摘要

以宁南退耕区采取的5种主要退耕模式--纯山杏林、山杏+柠条林、山杏+山桃+柠条林、沙棘林和苜蓿人工草地为研究对象,以撂荒地为对照,探讨不同退耕模式对土壤有机碳固存的影响.结果表明:在100 cm土层内5种退耕模式和撂荒对照的土壤有机碳储量基本上呈现出随土层深度加深而递减的趋势,其中浅层(0～20 cm)是土壤有机碳固存的聚集层,且极显著高于其他层的土壤有机碳累积;100 cm土层累积的总碳量表现为山杏+柠条林>山杏林>沙棘林>山杏+山桃+柠条林>撂荒地>苜蓿人工草地.从有机碳蓄积来看,在宁南山区采用单一的乔灌混交、乔木林或灌木林的退耕模式较采用人工草地或自然恢复的模式更有利于土壤有机碳的累积.%In order to find out the effect on soil organic carbon sequestration of different re-vegetation patterns, 5 main re-vegetation patterns, including pure wild apricot forest, wild apricot and Caragana korshinskii forest, wild apricot and wild peach and Caragana korshinskii forest, seabuckthorn forest and artificial alfalfa grassland were selected as the study objects, and the abandoned land were adopted as the control in southern Ningxia.It was shown that the soil organic carbon reserves of the 5 main re-vegetation patterns and abandoned land took on decreasing trend with the increase of soil depth basically within 100 cm soil layer, and the shallow layer (0-20 cm) was the accumulation layer of soil organic carbon sequestration, as soil organic carbon reserve in this layer was significantly higher than that in other soil layers.The total organic carbon sequestration in 100 cm layer decreased as wild apricot and Caragana korshinskii forest>pure wild apricot forest>seabuckthorn forest>wild apricot and wild peach and Caragana korshinskii forest>abandoned land>artificial alfalfa grassland.From the view of organic carbon accumulation, the re-vegetation patterns with arbor and shrub or pure trees forest or shrubs forest were more appropriate than artificial grassland or natural restoration for mountainous area in southern Ningxia.