科尔沁沙地土地利用变化对土壤特性的影响

在中国科学院奈曼沙漠化研究站放牧试验场周围,选取了不同利用方式和类型的草地（封育和放牧）、林地（乔木和灌木）和农田（灌溉和非灌溉）为研究样地,调查了0～30cm土层每隔10cm的土壤水分质量分数和有机养分（有机碳和全氮）,分析了土地利用变化对土壤水分质量分数和有机养分的影响。结果发现,垂直空间分布上,无论哪种土地类型样地,土壤水分质量分数和有机养分各土层间均无显著差异性（P〉0.05）,土层垂直变化对土壤特性影响均较小。在不同土地利用方式水平空间分布上,土壤水分质量分数和有机养分（土壤有机碳和全氮）灌木林地均显著高于乔木林地（P〈0.05）,而封育草地和放牧草地间以及灌溉农田与非灌溉农田间土壤水分质量分数和有机养分均无显著差异性（P〉0.05）。不同土地利用类型水平分布上,草地土壤水分质量分数显著低于林地和农田（P〈0.05）,而土壤养分质量分数草地显著高于林地和农田（P〈0.05）。分析表明,对沙质草地进行围栏封育和旱作农田退耕还林还草的同时,对水浇农田实行保护性耕作和精细管理,有利于沙地土壤环境改善与生态系统恢复。

Effect of land use changes on soil properties in Horqin sandy land

Based on Naiman Desertification Research Station,CAS,three types of land use were chosen as study sites under different management,such as grassland（enclosure and free grazing grassland）,forest stands（tree and shrub stand） and farmland（irrigated and no irrigated land）.The results were shown that no significant difference in soil properties was found vertically（P0.05）,whatever types of land use,which implied that vertical changes in soil depth of 0-30 cm had no effect on soil properties in Horqin Sandy Land.At different trend of one type of land use such as in forestry lands,the soil water and organic nutrients（total soil organic carbon and soil nitrogen content） were significant higher（P0.05） within shrub stands than within tree stands,while no significant differences（P0.05） were found between enclosure and free grazing grassland or between irrigated and no irrigated land.At the different types of land use,the soil water content was significantly lower on grasslands than on forestry lands and farmland（P0.05）,but the soil organic nutrients was significantly higher on grasslands than on forest stands and farmland（P0.05）.In conclusion,the sandy grassland was enclosed and the farmland was back for forests or grassland under the protective cultivation and careful management,both were beneficial for the recovery of soil ecosystem,thus to combat the desertification in Horin Sandy Land.