大兴安岭南部落叶松人工林与3种典型天然植被对立地土壤性质影响的差异

摘要

作为受人类干扰的特殊群落,人工林对林下土壤理化性质的影响作用一直备受争议. 在相似立地条件下,分析了大兴安岭南部常用人工树种(落叶松)与蒙古栎、山杏和草地3种典型天然植被对土壤理化性质影响的差异. 结果表明,4种植被类型土壤质地均为粉砂壤土,0~40 cm土壤容重由小到大依次为蒙古栎( 1. 06 g·cm-3 )、落叶松( 1. 07 g·cm-3 )、山杏( 1. 21 g·cm-3 )和草地( 1. 23 g·cm-3 ) ,说明蒙古栎天然林和落叶松人工林土壤具有更好的通气保水性. 土壤化学性质分析表明,除草地深层土壤磷素含量外,各植被类型土壤有机质、全氮、全磷、全钾含量均符合全国第2次土壤普查养分一级标准. 落叶松人工林土壤酸度( pH值5. 84)在落叶松天然林土壤适宜酸度范围内( 5. 5~6. 8). 随着土壤深度的增加,各植被类型土壤养分含量呈递减趋势. 主成分分析表明,与天然灌草相比,落叶松人工林土壤性质更好,但与蒙古栎天然林相比,落叶松人工林土壤性质略差. 认为研究区落叶松人工林建设不会造成土壤性质衰退.%Impacts of artificial forests, being a special category of biological communities under human interference, on soil properties, have long been an issue of controversy. Hence, a tract of Larix plantation, quite common in the area, and three tracts of other natural types of vegetation ( Quercus mongolica, Prunussibirica and grassland) under similar natural conditions were selected in the South Da Hinggan Mountains for investigation of impacts of vegetation on soil properties. Results show that the soils under the four types of vegetation were all silt loam in texture, and 1.06 g·cm-3( Quercus mon-golica),1.07 g·cm-3(Larix spp.), 1.21 g·cm-3(Prunussibirica) and 1.23 g·cm-3(grassland) in bulk density, 0-40 cm in depth, indicating that the soils under the artificial Larix plantation and natural Quercus mongolica woodlot were bet-ter than those under the two others in aeration and moisture retention. Analysis of soil chemical properties shows that all the items of soil nutrients, i.e. organic matter, total nitrogen, total phosphorus, and total potassium, in the soils under all the four types of vegetation, except for total N in the deep soil layers under grassland, were up to Criteria Grade I of the Stand-ard for Soil Nutrients for the Second National Soil Survey. However, soil nutrients decreased in content with increasing of soil depth. The soil under the artificial Larix woodlot was 5.84 in pH, right in the range of soil acidity (5. 5-6. 8) for nat-ural Larix forests to survive in. And principal component analysis shows that the soil under artificial Larix woodlot was bet-ter than that under grassland, but slightly worse than that under Quercus mongolica in soil properties. Based on the above findings, it could be concluded that the plantation of Larix forest would not lead to deterioration of soil properties.