山毛豆在岩溶区石漠化治理中的作用
Role of Tephrosia candida DC. in rocky desertification in Karst areas
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摘要: 为探讨山毛豆对岩溶区石漠化治理的作用,在广西凌云县典型的石漠化治理示范点阁楼村和加尤镇,在椿树和板栗树林下种植山毛豆和合萌,以坡地种植山毛豆作对照,通过定点监测植被多样性和土壤中养分的变化情况。结果显示,岩溶区种植山毛豆后第1 年,植被盖度达到20%~70%,第2 年提高到95%~100%,水涵养性提高了3.85%~10.3%,野生物种有害数减少20%~30.7%,土壤有效氮提高6.14%~14.61%,全磷提高23.02%~51.66%,全钾提高38.10%~45.24%,有机质提高6.28%;86.7% 的区域土壤有机质属于中等及以上等级,必需微量元素Cu、Mn、Ni、Mo、Sn 等有益元素得到提高,有害金属元素中除了Cr 外Pb、Ag、As、Hg 等均明显减少,其中Hg 由原来的三级标准提高到二级标准;阁楼对照区土壤pH 值第2 年比第1 年降低6.47%~10.59%,而山毛豆种植区提高0.40%~6.63%。表明种植山毛豆可以提高石漠化地区植被盖度,提高土壤水涵养性、有效氮和pH 值,可以减少野生有害物种的数量和土壤中有害金属元素的含量,具有强大的保持水土和恢复生态环境的作用,可促进石漠化地区土壤和植被正向恢复的演替。Abstract: In order to understand the role of Tephrosia candida DC. in rocky desertification management in Karst areas,we conducted the program in Gelou village and Jiayou town,typical pilot sites of rocky desertification management in Guangxi,planted T. candida and Aeschynomene indica L. under Cedrela wood and Chestnut wood, while planted T. candida on slope as control group,and detected the vegetation diversity and changes in soil nutrients. The results showed that,by planting T. candida in Karst areas,the vegetation coverage reached 20%-70% in the first year,and increased to 95%-100% in the second year;water conservation increased by 3.85%-10.3%; harmful wild species in the second year decreased by 20%-30.7% over the first year;soil available nitrogen was remarkable improved by 6.14%-14.61%,total phosphorus and potassium content increased by 23.02%-51.66% and 38.10%-45.24% respectively,organic matter raised by 6.28%,soil organic matter of 86.7% of the area belonged to medium and higher grade;essential trace elements in the soil,such as Cu,Mn,Ni,Mo,Sn content increased; the harmful metal elements except Cr,Pb,Ag,As,Hg content decreased obviously,and Hg was taken to the second standard from third standard;soil pH of Gelou village,the control group,in the second year decreased by 6.47%-10.59% over the first year,but that of T. candida area increased by 0.4%-6.63%. The result revealed that, planting T. candida in rocky desertification area could increase vegetation coverage,improve soil available nitrogen content,water conversation and soil pH,could decrease harmful wild species and harmful metal elements,played a powerful role in soil conversation and renovating ecologic environment,facilitated positive evolution of soil and vegetation in rocky desertification area.