晋西黄土区土地利用方式对土层有机质变异的影响

Effect of land use type on variability of soil organic matter content with soil depth in the loess region of western Shanxi Province

为揭示晋西黄土区不同土地利用方式下有机质的土层变异特征及其影响因素,选取刺槐林地、油松林地、荒草地和农田（玉米）坡地4种样地,分析土地利用方式、坡位、土层深度和土壤水分含量对土壤有机质含量的影响。结果表明,不同土地利用方式下土壤有机质含量大小顺序为：油松林地〉刺槐林地〉荒草地〉农地;坡位对土壤有机质含量及变异系数的影响复杂,难以出现一致性规律;随土层深度增加,不同土地利用方式下土壤有机质含量差异显著,但均随着土层深度的增加而不断减小且变异性减弱;两种林地和草地32-160 cm土层土壤水分与有机质含量呈显著正相关关系,而对于表层土壤和农地二者关系不密切。逐步回归分析表明,土层深度对土壤有机质空间变异影响最大。研究结果对晋西黄土区水土保持中林草措施的配置和生态环境建设有一定的参考价值。

To reveal the variability of soil organic matter content with soil depth under different land use type and its in- fluencing factors in the loess region of western Shanxi Province, four typical land use types including waste grassland （WL）, agricultural land （AL）, Robinia pseudoacacia forestland （RF） and Pinus tabuliformis forestland （PF） were chosen to ascertain the variability of organic matter content. It was shown that the order of soil organic matter content was PF〉RF〉WL〉AL. Slope position exerted a complicated influence on soil organic matter content, and the regularity of conformity was hard to find. With the increase of soil depth, soil organic matter content was significantly different under different land use patterns, while the content of organic matter in all typical land decreased, and the variability also decreased. Stepwise regression analysis showed that the soil depth was the dominated factor. Under PF, RF and WL, significantly positive relationship was available between soil moisture and organic matter content in the layer of 32-160 cm. The results are beneficial to the soil and water conservation and eco-environment construction in the loess region of western Shanxi Province.