黄土高原刺槐人工中龄林土壤碳汇

Soil Carbon Sequestration in a Middle-aged Black Locust Plantation in the Loess Plateau

以黄土高原26年生人工刺槐（Robinia pseudoacacia）林为对象,在调查了5个样地和测定125个碳含量数据的基础上,分析了造林后土壤有机碳密度的变化特征与造林对土壤碳增汇的效应。结果表明：在研究的0-80cm土层范围内,26年生刺槐林林地土壤有机碳密度（4.093 kg.m-2）与荒地（4.533 kg.m-2）相比,减少了0.440 kg.m-2,说明黄土高原荒地刺槐造林不能提高土壤有机碳密度。对土壤分层研究表明：荒山刺槐造林明显改变了原土壤有机碳密度分布,表现为：在0-10 cm土层范围,有机碳密度显著提高（33.4%）;在10-30 cm土层范围内,有机碳密度则明显降低（45.5%）。通过土壤层中总有机碳密度的研究显示,由于根系有机碳不断积累,林地总有机碳密度（5.214 kg.m-2）比荒地（4.688 kg.m-2）明显增加,土壤中总碳增汇率为11.2%,说明黄土高原刺槐造林具有显著的碳汇能力。

The variation characteristics of soil organic carbon（SOC） density and the effects of soil carbon sink enhancement after afforestation were analysed on the basis of the investigation of 5 sample plots and 125 data of carbon content by taking a 26-year-old black locust（Robinia pseudoacacia） plantation in Loess Plateau as the research object.In 0-80cm soil layer,SOC density of the black locust plantation（4.093kg·m-2） decreased by 0.440kg·m-2 compared with wasteland（4.533kg·m-2）,indicating that the SOC density can not be improved by planting black locust in wasteland of Loess Plateau.The SOC density in different soil layers showed that planting black locust in wasteland significantly changed the distribution of SOC density,namely SOC density increased by 33.4% in the 0-10cm soil layer and decreased by 45.5% in the 10-30cm soil layer.Total SOC density of forestland（5.214kg·m-2） increased significantly compared with wasteland（4.688kg·m-2） due to the continuous accumulation of organic carbon in root.The total carbon sink rate of the locust plantation was 11.2%,which shows that the black locust afforestation in the Loess Plateau has a huge potential for carbon sink.