中国南方典型富硒区土壤硒有效性调控与评价

摘要

多目标区域地球化学调查发现中国南方酸性土壤的硒含量普遍较高,但其生物有效性一般较低,土壤硒有效性直接关系到富硒土地资源的可利用性,而土壤酸碱度是影响土壤硒生物有效性的重要因素.本文选取福建、海南富硒红壤(pH为3.91 ～4.98)、富硒水稻土(pH为4.33～5.75),以生石灰、燃煤炉渣为改良剂,分别设置6个实验处理以调控土壤硒生物有效性.结果表明:添加生石灰和燃煤炉渣均能提升南方酸性土壤的pH,上升幅度在1～2个pH单位,从而有利于土壤中硒元素的活化,显著提高了土壤中硒元素的生物有效性;燃煤炉渣用量与其10倍的生石灰对提升土壤硒有效度的效果相当,而燃煤炉渣作为调控物料更为经济、实用,既可以实现炉渣的有效利用,又可以改善土壤结构、提高土壤硒有效度.%The multi-purpose regional geochemical survey showed that the concentration of selenium in acid soil in Southern China is generally high,but the bio-availability of selenium in soil is relatively low,which affects the usage of selenium-rich soil.The pH values of soils are an important factor affecting the bio-availability.Se-rich red soil samples with pH of 3.91-4.98 and Se-rich paddy soil samples with pH of 4.33-5.75 were collected from Fujian Province and Hainan Island.Six experiments were conducted using lime and coal slag as the modifier to improve the bio-availability of selenium in soil.The results show that soil pH can be significantly elevated by 1 to 2 units by using the modifiers,which advances the mobility of Se in soils and improves selenium bio-availability in soils.Coalcinder and 10 times weights of quicklime have the same effect to promote selenium availability.The coalcinder as a regulation material is more economical and practical.It can not only realize the effective utilization of cinder,but also improve the soil structure and increase the soil selenium availability.