石羊河流域干旱荒漠区人工梭梭林对土壤碳库的影响

采用野外调查与室内分析相结合的方法,研究石羊河流域民勤干旱沙区种植人工梭梭林4,13,36年后的土壤有机碳(Soil organic carbon,SOC)、无机碳(Soil inorganic carbon,SIC)、全氮(Total nitrogen,TN)和总碳(soil total carbon,TC)含量及储量变化特征。结果表明:流动沙地种植梭梭后,0-50cm层灌丛下和行间SOC和TN含量总体随造林年限增加而增加,5-50cm层灌丛下SIC含量在13年梭梭林地最高。36,13年林地0-50cm层灌丛下SOC和TN储量均高于行间,而13年灌丛下SIC储量低于行间,4年灌丛下5-50cm层SOC、TN和SIC储量均低于行间。0-50cm层土壤有机碳、无机碳、全氮储量增幅分别为102.44%,24.66%,54.55%,36年林地SOC和TN储量随土层加深先降低后增加,但4,13年和流动沙地SOC、SIC和TN储量均随土层加深而增加。土壤有机碳占总碳比例随造林年限增加而增加。相关分析结果表明,土壤颗粒组成、造林年限、土层深度等与土壤有机碳和全氮储量显著相关(P0.01)。民勤干旱沙区造林提高了土壤碳库截存量,并且随林龄增长而增长。

Effect of Artifical Haloxylon Ammodendron Plantation on Soil Carbon Pools in Arid Desert Region of Shiyang River Basin

This study evaluated the effects of artificial Haloxylon ammodendron plantation on the concentrations and storages of soil organic carbon (SOC), soil inorganic carbon (SIC), total nitrogen (TN) and total carbon (TC) by field investigation and laboratory analysis in Minqin desert regions. And the ages of H. ammodendron plantations were 4,13, and 36 years old, respectively. Results showed that the concentrations of SOC and TN in soils of 0-50 cm depth under shrubs and between shrubs both increased with the increasing of plantation age after afforestation, whereas the highest concentrations of SIC in 5-50 cm depth soil under shrubs were observed in 13-year-old plantations. Generally, the storages of SOC and TN were both higher under shrubs than those of between shrubs in 13- and 36-year-old plantations. However, the storage of SIC was less under shrubs than that between shrubs in 13-year-old plantations. And in the soils of 5-50 cm depth, the storages of SOC, SIC and TN were less under shrubs than those of between shrubs in 4-year-old plantations. In the soils of 0-50 cm depth, the storages of SOC, SIC and TN increased by 102.44%, 24.66% and 54.55%, respectively, after afforestation. Additionally, the storages of SOC and TN declined firstly and then increased with the increasing of soil depth in 36-year-old plantation, whereas the storages of SOC, SIC and TN all increased with the increasing of soil depth in shifting sandy land, 4- and 13-year-old plantations. Overall, the proportion of SOC to TC increased with increasing of afforestation age. Pearson''s correlation analysis indicated that storages of SOC and TN were both significantly correlated with soil particle size distribution, soil bulk density, plantation ages and soil depth. Therefore, we concluded that afforestation in arid desert region largely improved the accumulation of soil organic carbon and total carbon pools, and the carbon storage of soil increased with the growth of forest age.