黄土丘陵区不同退耕还林措施的土壤碳汇效应
黎 鹏1, 张 勇2, 李夏浩祺3, 孙彩丽4, 段奥华1, 刘国彬1,5

(1.西北农林科技大学 水土保持研究所, 陕西 杨凌 712100; 2.陕西省林业科学院, 西安 710082; 3.西北农林科技大学 资源与环境学院, 陕西 杨凌 712100; 4.贵州民族大学 生态环境工程学院, 贵阳 550025; 5.中国科学院 水利部 水土保持研究所 黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西 杨凌, 712100)

退耕还林(草); 有机碳储量; 恢复类型; 恢复年限; 土层深度

Effect of Soil Carbon Sink in the Hilly Region of the Loess Plateau Under Grain for Green Project
LI Peng1, ZHANG Yong2, LI Xiahaoqi3, SUN Caili4, DUAN Aohua1, LIU Guobin1,5

(1.Institute of Soil and Water Conservation, NorthwestA&F University, Yangling, Shaanxi 712100, China;2.Shaanxi Academy of Forestry, Xi'an710082, China;3.College of Natural Resources and Environment,NorthwestA&F University, Yangling, Shaanxi 712100, China;4.College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang 550025, China;5.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS&MWR, Yangling, Shaanxi 712100, China)

Grain for Green; soil organic carbon storage; restoration type; restoration ages; soil depths

备注

为分析黄土高原退耕还林(草)后土壤有机碳储量变化特征,选取不同土层深度(0—20 cm,0—30 cm,0—50 cm和0—100 cm)和不同恢复年限的刺槐林(5,10,20,56 a)、沙棘林(5,10,20,30 a)、柠条林(10,20,36,47 a)及草地(5,10,15,20,25,30 a)土壤为研究对象,通过测定土壤有机碳(SOC)含量,分析了植被恢复后土壤有机碳储量变化规律,并探讨了0—20 cm和0—100 cm土层土壤有机碳储量的关系。结果表明:4种退耕方式下,各土层土壤有机碳储量和0—100 cm土壤有机碳加权平均含量随恢复年限整体呈增加趋势; 同时,通过对比0—20 cm土层土壤碳储量随恢复年限变化速率发现,沙棘[0.048 g/(kg·a)]>刺槐[0.023 g/(kg·a)]>撂荒[0.020 g/(kg·a)]>柠条[0.012 g/(kg·a)]。此外,线性回归表明0—20 cm土层与0—100 cm土层土壤有机碳储量呈极显著正相关关系(F=169.6,R2=0.755,p<0.001)。综上,退耕还林(草)能够显著提高土壤有机碳储量,从土壤有机碳蓄积的角度考虑沙棘更有利于土壤有机碳的积累,同时可以用0—20 cm土层土壤有机碳储量来估算退耕还林的固碳潜力。
With the aim to analyze the variation characteristics of soil organic carbon reserves after returning cropland to forest(grassland)on the Loess Plateau, soil with different depths(0—20 cm, 0—30 cm, 0—50 cm and 0—100 cm)and various vegetation with different restoration ages including Robinia pseudoacacia (5 a, 10 a, 20 a and 56 a), Caragana korshinskii(5 a, 10 a, 20 a and 30 a), Hippophae rhamnoides(10 a, 20 a, 36 a and 47 a)and natural grassland(5 a, 10 a, 15 a, 20 a, 25 a and 30 a)were selected as the objects of this study, the law of soil organic carbon(SOC)reserves after vegetation restoration was analyzed, and the relationship between soil organic carbon reserves in 0—20 cm soil layer and 0—100 cm was discussed. The results showed that soil organic carbon reserves of each soil layer increased with the recovery years in four restoration patterns. Meanwhile, the carbon sequestration rate of the 0—20 cm soil layer followed the order of Caragana korshinskii [0.048 g/(kg·a)]>Robinia pseudoacacia [0.023 g/(kg·a)]>natural grassland [0.020 g/(kg·a)]>Hippophae rhamnoides [0.012 g/(kg·a)]. In addition, a significant positive correlation was found between soil organic carbon of 0—20 cm soil layer and 0—100 cm soil layer(F=169.6; R2=0.755; p<0.001). Overall, Grain for Green project can significantly increase SOC storage, and Caragana korshinskii is more conductive to SOC accumulation, compared with other treatments. In addition, the SOC of 0—20 cm soil layer could be used to estimate the potential carbon sequestration of conversion of farmland to forest. This study is conducive to enhancing the understanding of soil carbon sequestration during vegetation restoration in the Loess Plateau and providing theoretical reference for regional carbon cycle.