水土保持研究2012，Vol.19Issue(4)：43-47,52,6.
黄土丘陵区不同退耕还林地土壤有机碳、氮密度变化特征
Change Characteristics of Density of Soil Organic Carbon and Nitrogen under Land Shifted into Forestland in Hilly Loess Region
摘要
Abstract
This study was conducted to determine the change characteristics of the density of soil organic carbon and total nitrogen and distribution in soil layers of 0—60 cm with 10~40 years of conversion of cropland to forest in Hilly Loess Region.The results showed that： compared different soil layers in forestland shifted from cropland for 10~40 years,the average organic carbon density in 0—20 cm soil layer of caragana,orientalis and robinia was 4.20,6.87,4.46 Mg/hm2,which was higher than that in 20—60 cm soil layer in caragana,orientalis and robinia forest land,respectively,and average nitrogen density was increased 0.08,0.02,0.07 Mg/hm2,which was higher than that in 20—60 cm soil layer,respectively.Compared with slope farmland,the organic carbon sequestration rate in 0—20 cm soil layer within 30 years of conversion of cropland to forestland follow the order of orientalis（0.33 Mg·hm^-2·a^-1）〉robinia（0.28 Mg·hm^-2·a^-1）〉caragana（0.17 Mg·hm^-2·a^-1）,and nitrogen sequestration rate follow the order of robinia（0.03 Mg·hm^-2·a^-1）〉orientalis（0.02 Mg·hm^-2·a^-1）〉caragana（0.01 Mg·hm^-2·a^-1）.The carbon and nitrogen sequestration rate of 0—20 cm soil layer was higher than that in deep soil layer.Average 57% of increased soil organic carbon and 51% of increased nitrogen were contributed by 0—20 cm soil during 10~30 years of conversion of cropland to forest.The ratio of C/N decreased with soil depth under all lands of conversion of cropland to forest.In conclusion,conversion of cropland to forestland could significantly increase soil carbon and nitrogen stocks,and orientalis was better for carbon sequestration and robinia was better for nitrogen sequestration.关键词
退耕还林/土壤有机碳/土壤全氮/黄土丘陵区Key words
conversion of cropland to forestland/soil organic carbon/soil nitrogen/Hilly Loess Region分类
农业科技引用本文复制引用
赵发珠,韩新辉,杨改河,佟小刚,康乐,杜约翰..黄土丘陵区不同退耕还林地土壤有机碳、氮密度变化特征[J].水土保持研究,2012,19(4):43-47,52,6.基金项目
国家自然基金 （）
教育部高等学校博士点基金 （）
陕西省自然科学基金 （）
