植被措施对土壤保育的作用及其影响因素分析

Effect of Vegetation Measures on the Soil Conservation and Factors Analysis

以我国不同水蚀区典型生态试验站实测资料为基础,研究了西北黄土区、南方红壤区、西南石漠化区及北方土石山区植被恢复措施对土壤保育的作用。结果表明,各个区域内林草地与耕地相比可以显著增加土壤中>0.25mm水稳性团粒含量、土壤空隙度并降低土壤容重,且林地恢复时间越长,对土壤结构改善的作用越明显。土壤中有机质和全氮含量也有类似规律。但不同区域内气候、土壤母质、植被类型等因素存在差异,使得各区域内植被恢复对土壤结构及肥力的改良效果存在差异。与对照样地相比,各类型区植被措施下的土壤中的全磷和全钾含量没有明显一致性变化规律,主要原因在于天然土壤中有机质和氮素最主要来源是植被凋落物,磷和钾主要与土壤类型、土壤形成母质等因素有关。

Based on data from ecological experiment stations located in the four typical water erosion regions （i.e., loess region in Northwestern China, red soil region in Southern China, stony desertification in Southwestern China, and earth-stony region Northern China）, the effect of vegetation restoration measure on soil texture as well as its fertility were studied. Results showed that vegetation restoration measures could greatly improve soil structure and its fertility. compared to cultivated land, the content of soil stable aggregate with size larger than 0.25mm and soil porosity increased greatly in the forest and grass lands, whereas soil bulk density decreased. This improvement in soil texture and its fertility became more and more apparent with time duration of vegetation restoration for the study area. Similarly, the content of soil organic matter （SOM） and total nitrogen （TN） had the same changing trend as that of the soil stable aggregate and soil porosity. However, because of differences of climate, soil parent material, and vegetation types et al., the effect of vegetation restoration measures on soil structure and its fertility were different in the four typical water erosion regions. Compared to the reference fields, the changing trends were different for the contents of soil total phosphorus （TP） and total Potassium （TK） under vegetation restoration measures in the four typical water erosion regions. The main reasons could be explained that SOM and TN mainly come from vegetation deciduous matter, while TP and TK mainly relates to soil parent material, and soil type etc.