中国西南岩溶区土壤允许流失量及防治对策

中国西南岩溶区碳酸盐岩成土物质先天不足,沿用1997年水利部颁布的《土壤侵蚀分类分级标准》(SL190—96),显然与岩溶区的实际情况不相适应。在分析影响西南岩溶区碳酸盐岩风化成土因素的基础上,收集了相关的资料、数据和图层,估算了西南岩溶区碳酸盐岩的风化成土速率,并将成土速率作为土壤允许流失量,重新厘定西南岩溶区水土流失强度的分级标准,微度、轻度、中度、强度、极强度和剧烈分别为<30、30~100、100~200、200~500、500~1 000、≥1 000 t/(km2.a)。同时根据西南岩溶区水土流失过程的基本特点,对该地区以后的水土保持工作提出4点建议:抓住水土流失过程关键环节重点防治;不同岩溶石漠化区采取不同水土保持对策;积极推进生物篱技术;加强岩溶区土壤改良技术研究,提高基本农田的生产效率。

Soil Loss Tolerance and Prevention and Measurement of Karst Area in Southwest China

The carbonate litho-soil substance of karst region in the southwest is congenital deficiency and can not suit to the actual situation of the karst region if continues to use "Classification Standard for Soil Erosion"(SL190-96) published by the Ministry of Water Resources in 1997.The paper collects related data and figures and estimates the weathering soil-forming rate of carbonate karst region in the southwest based on the analysis of the affecting factor of weathering soil-forming rate.It takes soil-forming rate as soil allowable loss and redecides the classification standard of the intensity of soil and water loss of the karst region as degrees of very slight,slight,medium,serious and very serious(<30,30~100,100~200,200~500,500~1 000 and >1000 t/(km2·a)) respectively.It puts forward the following four suggestions on future work about soil and water conservation in the region based on the basic characteristic of the process of soil and water loss: to prevent and control soil and water loss at the key links of process;to adopt different countermeasures of soil and water conservation for different karst desertification region;to actively carry forward techniques of living hedges;to strengthen the study on soil improvement of the karst region and to increase the production efficiency of basic farmlands.