【作者】 张平良；

【导师】 李小刚；

【作者基本信息】 甘肃农业大学 ， 土壤学， 2007， 硕士

【摘要】 植被是影响土壤有机碳含量和土壤结构的重要因素,植被通过凋落物影响有机碳输入的数量和质量,同时改善土壤结构。然而在高寒农牧交错带植被恢复对草地土壤有机碳库及土壤结构稳定性影响的研究不多。本研究以耕地为对照,对种植老芒麦草和撂荒两种植被恢复方式下土壤有机碳动力学和团聚体稳定性进行了定量研究,以评价植被恢复对高寒农牧交错带草地可持续利用的影响。本研究的主要结果如下:1.与耕地相比较,种植老芒麦草和撂荒使0-30cm土壤总有机碳含量分别增加了19.7～22.4%和7.3～10.6%,颗粒有机碳(2～0.05mm)含量分别增加了43.0～52.3%和28.7～59.8%,碳水化合物碳含量分别增加了13.8～27.9%和4.94～29.7%;使0-10cm土壤矿化碳含量分别增加了49.0%和14.4%,10-30cm无明显变化;使0-30cm土壤全氮含量分别增加了12.0～20.6%和5.4～13.7%。这一结果说明,在高寒农牧交错带通过种植老芒麦草或者撂荒恢复植被,对于提高土壤有机碳含量和全氮含量、恢复土壤质量的效果非常显著。2.与耕地相比较,种植老芒麦草和撂荒使0～30cm土壤水稳性团聚体稳定率分别增加了45～110%和45～113%,平均重量直径分别增加了11～65%和28～95%,表明在高寒农牧交错带通过种植老芒麦草或者撂荒恢复植被对提高土壤结构稳定性和抗侵蚀性有重要影响。3.土壤总有机碳、颗粒有机碳和碳水化合物碳含量均与土壤水稳性团聚体结构稳定率和平均重量直径显著线性正相关,说明草地植被恢复后土壤质量的改善与土壤有机碳含量的变化密切相关,颗粒有机碳和碳水化合物对水稳性团聚体稳定性起主要作用,进一步论证了种植老芒麦草和撂荒都可以通过植被的恢复导致土壤中颗粒有机碳和碳水化合物碳含量的显著增加,对提高土壤结构稳定性起着明显作用。上述研究结果说明,在高寒农牧交错带通过种植老芒麦草或者撂荒恢复植被,可以显著提高土壤有机碳含量,有利于提高水稳性团聚体稳定性和增强土壤抗侵蚀性,这对于该地区恢复土壤质量和改善生态环境具有十分重要的意义。更多还原

【Abstract】 Vegetation is one of important factor to affect the contents of soil organic carbon and aggregate, which increases the input of soil organic carbon and improves soil structure. However,the influence of vegetation restoration on soil organic carbon pools and soil aggregates stability in Agro-pastorally Transitional Alpine Region has not been well understood. This work was designed to investigate the changes in soil organic carbon dynamics and aggregates stability and their relations in cultivated alpine soil induced by Elymus sibiricus plantaion and abandonment, compared with cultivation and therefore we evaluated the influence of vegetation restoration on grassland sustainable development in Agro-pastorally Transitional Alpine Region. The main conclusions as following:1 Compared with cultivation, It was found that total soil organic carbon contents was increased by 19.7～22.4% and 7.3～10.6%, particulate organic carbon contents by 43.0～52.3% and 28.7～59.8%, carbohydrate carbon contents by 13.8～27.9% and 4.94～29.7%, total nitrogen contents by 12.0～20.6% and 5.4～13.7% at depth 0-30 cm in soils under Elymus sibiricus plantaion and abandonment after three years conversion from cultivated soil,mineral carbon contents was increased by 49.0%and 14.4% in 0-10cm depth, and which has not significant effect in 10-30cm depth. This result might indicate that Elymus sibiricus plantation and abandonment are advantageous to the soil organic carbon contents and total nitrogen contents enhancement, which are favorable to the improvement in cultivated alpine soil quality.2 Compared with cultivation, It was found that soil water stable aggregates ration was increased by 45～110% and 45～113%, and mean weight diameter by 11～65% and 28～95% at depth 0-30 cm in soils under Elymus sibiricus plantaion and abandonment after three years conversion from cultivated soil, This result might indicate that Elymus sibiricus plantation and abandonment have important influence on enhancing soil structure stability and improving soil anti-erosion.3 Our research indicated that soil total organic carbon contents and particulate organic carbon contents were all more closed linear relationships to soil water stable aggregates ration and mean weight diameter. But carbohydrate carbon content was also significant linear relationship to soil water stable aggregates ration. This result might indicate that it was closely related between improvement of soil quality and changing of soil organic carbon contents by vegetation restoration, particulate organic carbon and carbohydrate carbon have main function in water aggregates stability, This result further explained Elymus sibiricus plantaion and abandonment resulted in soil particulate organic carbon and carbohydrate carbon contents remarkably increased was the most directly reason of soil aggregate stability improvement.The above research results showed that, in Agro-pastorally Transitional Alpine Region Elymus sibiricus plantaion and abandonment may remarkably increase the soil organic carbon contents, meanwhile which are advantageous to improving soil water stable aggregates stability and increasing soil anti-erosion, thus this has very important meaning that vegetation restoration is advantageous to raising soil quality and improving ecosystem environment in this region.更多还原