黄土高原羊圈沟小流域土地利用时空变化的土壤有机碳效应  

Effects of spatio-temporal changes of land-use on soil organic carbon in Yangjuangou watershed in Loess Plateau,China

作　　者：文雯[1,2] 周宝同[3] 汪亚峰[1] 梁地[1] 

机构地区：[1]中国科学院生态环境研究中心城市与区域生态国家重点实验室,北京100085 [2]北京大学环境科学与工程学院,北京100871 [3]西南大学地理科学学院,重庆400715

出　　处：《生态学报》2015年第18期6060-6069,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金(40901098)

摘　　要：土地利用变化是影响土壤有机碳储量和分布变化的重要驱动因素,为进一步探讨土地利用变化对土壤有机碳的影响,根据土壤样点数据、土地利用类型图,分析了黄土丘陵沟壑区羊圈沟小流域2006—2011年土地利用变化及其对表层土壤有机碳密度和储量的影响,主要结论如下:(1)小流域土地利用发生较大变化,主要集中在乔木林地和灌木林地面积的增加,分别为39.697、46.404 hm2;以及草地面积的减少,为64.030 hm2;(2)土地利用方式的变化会导致土壤有机碳密度及储量的变化,其中转变用地类型的土壤有机碳储量增加587.25 kg,以荒草地转出类型增加的土壤表层有机碳储量最多,为441.64 kg;灌木林地转出类型减少的土壤表层有机碳储量最多,为-21.01 kg。草地-灌木林地、草地-乔木林地、坡耕地-草地、坡耕地-灌木林地、坡耕地-乔木林地、坡耕地-坝地、梯田-草地、梯田-灌木林地、梯田-乔木林地、梯田-坝地、坝地-草地、坝地-灌木林地、坝地-乔木林地等转换用地类型的表层土壤碳密度增加值高于保持用地类型碳密度的增加值,说明这些地类的转换有利于表层土壤有机碳储量的增加,即有利于表层土壤碳汇的形成;而其他地类转换造成了表层土壤的碳排放,应该引起足够的重视;(3)土壤固碳应着眼于长期效应,频繁的土地利用类型转化可能会降低土壤碳截流效果,黄土丘陵区植被重建的长期利用和保持更有利于土壤有机碳的积累。Land use change is an important driving factor for changes of storage and spatial distribution of soil organic carbon （SOC）. In order to study effects of land use change on SOC, we analyzed the spatio-temporal changes of land use and their effects on SOC content, density and storage of topsoil based on soil sampling data and land-use map from 2006 to 2011 in Yangjuangou watershed. The main conclusions include that, （1） Land use types in this watershed changed significantly from 2006 to 2011. The area of grass land, which mainly transformed into shrub land and arboreal land, decreased the most with 64.030 hm2, following by sloping farmland mainly transformed into terrace ; the area of shrub land and arboreal land increased rapidly by 39.697 hm2, and 46.404 hm2respectively, which were converted from the grass land, terrace, sloping farmland, dam land and construction land ; the area of terrace was so small that the transformation was not obvious. （2） Land use change caused change of density and storage of SOC. The increase of carbon storage due to land type changes was 587.25 kg, among which the contribution from changed land types converted from grass land was 441.64 kg. Within all the land use transformations, ＇ grass land to shrub land＇ , ＇ grass land to arboreal land＇ , ＇ sloping farmland to grass land＇ , ＇ sloping farmland to shrub land＇ , ＇ sloping farmland to arbor land＇ , ＇ sloping farmland to terrace＇ , ＇ sloping farmland to terrace＇ , ＇ terrace to grass land＇ , ＇ terrace to shrub land＇ , ＇ terrace to arboreal land＇ , ＇ terrace to dam land＇ , ＇ dam land to grass land＇ , ＇ dam land to shrub land＇ , and ＇ dam land to arboreal land＇ showed higher SOC densities than those of the original land use types. It indicated that these land use transformations were conducive to increase of surface SOC and reduction of carbon emissions, which were beneficial to formation of surface soil carbon sink. However, other land use transformations, which caused

关 键 词：土地利用变化 土壤有机碳 羊圈沟小流域 黄土丘陵地区 

分 类 号：S153.6[农业科学—土壤学]