滇东南岩溶地区三种退耕还林模式的水土保持效应研究

对滇东南岩溶地区3种退耕还林模式和坡耕地的径流和植被、土壤测定分析,结果表明：退耕地还林恢复植被后,能取到明显的固土保水增肥作用。营造纯林、乔草混交林或经济林与牧草复合经营,均具有较好的水土保持效果,综合考虑保水、保土和保肥能力,由大到小依次是：川滇桤木：红三叶〉墨西哥柏〉花椒：大百脉根。与坡耕地相比,川滇桤木与红三叶混交林能减少37．23％的径流和99．40％的土壤流失,固体养分流失量中有机质、全氮、全磷、全钾、速效氮、速效磷和速效钾分别减少99．37％,99．43％,98．68％,98．86％,99．34%,99．35％和99．58％,液体养分流失中氮、磷、钾分别减少32．45％,19．80％和21．57％。不仅减少了水土和养分的流失,同时枯枝落叶等有机质对土壤的改良和营养补充,使土壤养分有所提高,而坡耕地的土壤养分则有所下降。

Study on Conservation of Soil and Water in Three Different Forestation Modes in Karst Area of Southeastern of Yunnan

It analysed that runoff,plants and soil in three different forestation modes and hillside cultivation in Karst area of the southeastern of Yunnan.The results showed that returning land for farming to forestry had remarkably impact on soil buildup,water retention increased fertility.We also could get good effects of conversation of soil and water by constructing pure forest,mixed forest,and complex management of commercial forest and herbage.Size these plants down by comprehensive consideration to water retention, soil retention and fertility retention was Alnus ferdinandi-coburgii:Trifolium pratense>Cupressus lusitanica>Zanthoxylum bungeanum:Lotus uliginosus. Alnus ferdinandi-coburgi iand Trifolium pratense mixed forest could decrease runoff flow and loss of run-off soil 37.23% and 99.40% respectively than those of hillside cultivation.The loss of soil solid nutrition was also decreased, which organic matter,total nitrogen,total phosphorus,total potassium,alkaline hydrolysis nitrogen,available phosphorus,and available potassium respectively decrease 99.37%,99.43%,98.68%,98.86%,99.34%,99.35% and 99.58%.The loss of nitrogen,phosphorus and potassium in fluid nutrition was respectively decreased 32.45%,19.80% and 21.57%.Soil nutrition was increased because of decreasing loss of runoff soil and soil nutrition,meanwhile organic matter had some impact on soil reform and nutrition supplement.While soil nutrition in hillside cultivation had some certain decreased.