黄土丘陵区退耕植被土壤水分·可溶性碳氮的变化特征

[目的]研究黄土丘陵区植被恢复过程中土壤水分、可溶性碳氮的变化特征。[方法]选择刺槐(乔木)、柠条(灌木)、撂荒地(草地)3种退耕植被为研究对象,以坡耕地为对照,研究不同退耕植被下土壤水分、可溶性碳氮的季节和垂直分布。[结果]土壤水分、可溶性碳氮均受季节变化的影响,其中土壤水分表现为先降低后增加的趋势,可溶性碳氮的趋势相反;此外,与耕地相比,3种退耕植被土壤水分、可溶性碳氮均有较大的提高;随着土层的加深,土壤水分在表层(0~30 cm)整体表现为撂荒地较林地低,而30~200 cm土层,表现为撂荒地大于林地,深层土壤水分变化不显著。可溶性碳氮在0~30 cm土层也表现为随着土层的增加而递减趋势,且显著受土层变化的影响(P0.05)。另外,土壤水分、可溶性碳氮存在着显著相关性(P0.05)。[结论]该研究阐明了黄土丘陵区典型退耕植被的土壤水分、可溶性碳氮的动态变化规律,为进一步分析和评价黄土丘陵区土壤养分状况提供科学依据。

Change Characteristics of Soil Water Content,Dissolved Organic Carbon/Nitrogen Following Afforestation in Hilly Loess Region

Objective] In order to study the changes of the soil water content ( SWC) , dissolved organic carbon and nitrogen ( DOC/DON) during the vegetation restoration on the Loess Hilly Region of China.[ Method] Robinia pseudoacacia L., Caragana korshinskii Kom, and a-bandoned land, were selected, with slope farmland as control.The seasonal and vertical distribution of SWC and DOC/DON under different kinds of vegetation were studied.[ Result] The results showed that SWC, DOC, and DON were affected by seasonal variations; the SWC showed the increasing after decreasing trend, while both the DOC and DON showed the contrary.Additionally, compared to the farmland, af-forestation greatly increased the SWC, DOC and DON.Furthermore, SWC showed the trend of abandoned land