巢湖典型低山丘陵区不同土地利用类型壤中流养分流失特征

摘要

以巢湖典型低丘山区坡地的6种主要土地利用类型(弃耕地、尾矿裸地、灌木林地、荒草地、马尾松林地和人工恢复林地)为研究对象,通过定位观测与收集坡面壤中流,探讨该地区壤中流养分流失动态变化特征.结果表明,巢湖低丘山区典型土地利用类型壤中流发生概率为灌木林地和荒草地较高,尾矿裸地最低(仅在0～20 cm土层产生)；表层壤中流氮含量为尾矿裸地最高,人工恢复林地最低,壤中流磷含量为弃耕地最高,尾矿裸地最低；壤中流氮素流失以溶解态NO3--N为主,并随雨季的到来而呈下降趋势,随土层加深呈先下降后升高趋势；磷主要以有机溶解态形式流失,随土层加深而呈下降趋势.相关分析表明,地表总盖度、地表植被均匀度、土壤养分含量与壤中流氮、磷含量间存在显著相关性,而降雨特征(降雨量、降雨强度)与壤中流氮、磷含量间相关性不显著.由于人为开采严重,在分析该地区壤中流氮素含量时,应注意干湿沉降的影响.%Six major types of land use ( deserted farmland, bare land, shrub land, grassland, Pinus massoniana forest, and artificially restored forest) in the low hill region of Caohu Basin were chosen as subjects in a study to explore for characteristics of soil nutrient loss with soil interflow as affected by the land use in the region. Stationary observation and sampling of soil interflows for analysis were conducted. Results show that among the six types of land use, shrub land and grassland were the highest in probability of interflow occurrence, while bare tailing land was the lowest and had interflows only in the top 20 cm soil layer. For the nitrogen concentration in soil interflow, it was found the highest in bare tailing land and the lowest in artificially restored forest. However, phosphorus content in interflow was the highest in deserted farmland and the lowest in bare tailing land; Specifically, the nitrogen in soil interflow was found mainly in the form of dissolved NO3- -N, of which the concentration displayed a decreasing trend with the arrival of the rainy season, but a falling and then rising trend with soil depth. The phosphorus lost with soil interflow was mainly in the form of dissolved organic phosphorus, of which the concentration displayed a decreasing trend with soil depth. Correlation analysis showed that both nitrogen and phosphorus concentrations in soil interflow were significantly related with total land coverage, vegetation evenness and soil nutrient level, but insignificantly with amount and intensity of rainfall. Owing to the flourishing mining industry in the region, it is important to take into account the effect of dry and wet depositions when analysis is done of N content in soil interflow in the region.