硒在草地放牧系统“土壤-植物-动物”间的流动与调控

摘要

硒(Se)作为动物必需而容易缺乏的微量元素,具有多种生物学功能.在草地放牧系统中,硒随着物质在土壤、植物和动物之间的转移而循环流动.本文从硒在放牧草地“土壤-植物-动物”间的含量、分布及功能等方面,对国内外的研究现状进行了综述,分析了硒在放牧系统中的循环流动特点.结果表明,硒在土壤、植物和动物中的含量分别为0.1～2.0、0.05～1.50和0.02～0.05 mg·kg-1.受多种因素影响,硒在土壤、植物和动物之间的流动量存在较大差异且不稳定,导致放牧家畜往往容易出现硒元素摄入不足的现象.在合理的放牧制度下,采取适宜的施肥方式,补播对硒积累能力强的牧草品种,可有效增加草地放牧系统中硒的循环流动量,以缓解或解决放牧家畜缺硒的不利局面.%The trace element selenium has various biological functions and is essential for animal health.There is considerable transference of substances in the grassland grazing system and,therefore,selenium circulates through the soil into plants and animals.This review summarized the recent research studies on various aspects of the circulation of selenium including its content,distribution,and functions in soil,plants,and animals.In addition,we analyzed the cyclic characteristics of selenium in the grassland grazing system.The results showed that the content of selenium in soil,plants,and animals was 0.1～2.0,0.05～1.50,and 0.02～0.05 mg · kg-1,respectively.The circulation of selenium in the soil,plants,and animals is affected by numerous factors and has exhibited considerable differences and instability,which has led to consistent deficiencies in its intake by grazing animals.The implementation of a reasonable grazing system would efficiently increase the circular flow of selenium by initiating appropriate fertilization methods and reseeding selenium-enriched forage.We believe these strategies would relieve or resolve the current situation where grazing livestock consistently show deficient selenium levels.