黄土丘陵区不同退耕还林地土壤颗粒结合态碳库分异特征  

Variances of carbon storage in soil particle-sized fractions following conversion of cropland to forest in Loess Hilly Region

作　　者：佟小刚[1,2] 韩新辉[3] 李娇[1] 杨云芬[1] 王健[1] 

机构地区：[1]西北农林科技大学资源环境学院,杨凌712100 [2]农业部西北植物营养与农业环境研究重点实验室,杨凌712100 [3]西北农林科技大学农学院,杨凌712100

出　　处：《农业工程学报》2016年第21期170-176,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(41301602);国家林业公益性行业科研专项(201304312);中央高校基本科研业务费专项(2452015269)

摘　　要：为揭示黄土丘陵区不同退耕还林土壤有机碳库差异及变化机制,比较分析了15 a生刺槐、山杏、杨树、沙棘、柠条5种退耕还林地土壤砂粒（≥53-2000μm）、粉粒（≥2-53μm）、黏粒（〈2μm）结合碳的质量分数与分布变化状况。结果表明,与坡耕地比较,不同退耕林地从表层0-10cm到〉40-60 cm土层土壤总有机碳质量分数增加了1.0-1.9 g/kg,砂粒碳、粉粒碳、黏粒碳质量分数分别增加了0.5-0.1、1.0-0.6、0.4-0.3 g/kg。同时,各林地0-20 cm土层土壤总有机碳和粉粒碳密度差异为杨树=柠条〈沙棘〈山杏〈刺槐,两种碳库增幅分别为2.4-5.8和1.2-3.5 Mg/hm2;但不同林地该土层黏粒碳和砂粒碳基本无显著差异,平均增幅分别为0.7和0.9 Mg/hm2。土层深度为0-60 cm时,土壤总有机碳、粉粒碳、黏粒碳密度均表现为沙棘=杨树=柠条〈山杏=刺槐,3种碳库增幅分别7.1-12.1、3.8-6.8、1.8-3.2 Mg/hm2;该土层砂粒碳密度在不同林地间仍无显著差异,平均提高了1.5 Mg/hm2。不同林地土壤颗粒碳组分占全有机碳比例均以粉粒碳最高（56.8%）、黏粒碳次之（29.3%）,砂粒碳最低（13.8%）。综上,不同退耕林地均以粉粒碳为土壤碳库变化和累积的主要形式,但以刺槐和山杏林提升退耕土壤总有机碳及颗粒碳组分库效应最明显,可作为该区域优选的退耕还林生态固碳技术。With the implementation of Grain for Green Project in the Loess Hill region of China, a large amount of arable land has been replaced by shrubs and trees, resulting in increased storage of soil organic carbon （SOC）. To elucidate the mechanisms of change in the SOC and differences in the storage of SOC among the afforested lands, we separated the whole SOC into three particle-sized fractions： sand associated carbon （sand-C, ≥153-2000μm）, silt associated carbon （silt-C, ≥ 2-53μm） and clay associated carbon （clay-C, 〈2μm）. Soils were collected from cropland land and from areas with five tree species, robinia （Robiniapseudoacacia L）, apricot（Armeniacasibirica）, poplar （Populustomentosa）, buckthom （Hippophaerhamnoides L） and caragana （Caraganakorshinskii）, which have grown on former cropland for 15 years. The result showed that compared with cropland, the content of SOC in whole soil at all afforested lands were significantly increased by 1.9-1.0 g/kg from top soil of 0-10 cm to soil depth of 〉40-60 cm, while the content of silt-C, elay-C and sand-C was increased by 1.0-0.6, 0.4-0.3, 0.5-0.1 g/kg, respectively. As a result, the stock of whole SOC and silt-C in 0-20 cm soil depth followed the increased ordercaragana = poplar〈 buckthom 〈 apricot 〈robinia, and increased 2.4-5.8 and 1.2-3.5 Mg/hm2, respectively. Carbon in the clay-C and sand-C fraction in the shallow soil layer was not significant differences among the afforested lands, and averagely increased 0.7 and 0.9 Mg/hm2, respectively. Moreover, the stock of whole SOC, silt-C and clay-C in soil depth of 0-60 cm was in the order caragana = poplar = buckthom 〈 apricot 〈robinia, and increased by 7.1-12.1, 3.8-6.8 and 1.8-3.2 Mg/hm2, respectively. There were no differences for sand-C stock in the 0-60 cm soil layer among the afforested sites, and the sand-C averagely increased 1.5 Mg/hm2 compared with cropland. However, the variation of sand-C stock was 1.6 times higher than the variation in silt-C and clay-C

关 键 词：土壤 有机碳 颗粒 黄土丘陵区 退耕还林 黄绵土 

分 类 号：S157.2[农业科学—土壤学]