地质高背景区富Se耕地可利用性研究及区划建议

Availability of Se-rich Arable Land in High Geological Background Area and Suggestions for Zoning

为了促进土地质量地球化学调查成果服务于特色土地资源开发,实现地质高背景区富Se资源的安全利用,以重庆市黔江区五里镇为研究对象,通过评价土壤-农作物的富Se水平及重金属含量,开展地质高背景区富Se耕地区划及可利用性方法研究,以期提高富Se资源利用效率,为地质高背景区富Se资源的安全利用提供思路.结果表明,研究区土壤及农作物中Se含量丰富,具备开发富Se资源的潜力,但部分样品存在Cd超标的问题.土壤pH是影响农作物Se和Cd含量的关键因素,碱性条件下有利于富Se资源安全利用.A~E(A表示可利用富硒耕地,B表示农作物不富硒但农作物安全,C表示农作物富硒但农作物不安全,D表示农作物不富硒且农作物不安全,E表示土壤硒含量小于富硒阈值且土壤重金属不超标)类耕地面积分别为0.72、0.75、0.28、0.13和0.56 km^(2),建议在A类耕地分布区开展安全富Se资源开发,在C和D类耕地分布区开展土壤酸化调理及作物低累积品种等农艺措施,降低农作物重金属超标风险,并加强全区耕地保护力度,防止新增污染物输入.

In order to promote the results of land quality geochemical surveys to serve the development of characteristic land resources and realize the safe utilization of Se-rich resources in high geological background areas,Wuli Town,Qianjiang District,Chongqing City were taken as the research object to evaluate the Se-rich level and heavy metal content of soil crops and carry out research on Se-rich cultivated area division and the availability method system in the high geological background area,in order to improve the utilization efficiency of Se-rich resources and provide ideas for the safe utilization of Se-rich resources in high geological background areas.The results showed that the soil and crops in the study area were rich in Se and had the potential to develop Se-rich resources,but some samples had the problem of excessive Cd.Soil pH was a key factor affecting the content of Se and Cd in crops,and alkaline conditions were conducive to the safe utilization of Se-rich resources.The areas of Class A-E(A:selenium-enriched arable land,B:crops that were not selenium-enriched but were safe,C:crops that were selenium-enriched but unsafe,D:crops that were not selenium-enriched and unsafe,and E:soil selenium content less than the selenium-enriched threshold and soil heavy metals not exceeding the standard)cultivated land were 0.72,0.75,0.28,0.13,and 0.56 km^(2),respectively.It is recommended to develop safe and Se-rich resources in the distribution area of Class A cultivated land and to carry out soil acidification conditioning and low-accumulation crops in the distribution area of Class C and D cultivated land;other agronomic measures should be taken to reduce the risk of excessive heavy metals in crops and strengthen the protection of cultivated land in the region to prevent the input of new pollutants.