广西区域富硒土壤硒素特征及其活化机理研究

Selenium has the effects of preventing and curing of diseases, improving health and slowing down the aging, and so on, thus Se-enriched products get the present people to pay more and more attention to health. Area of 2.12 million ha of selenium-rich soil in Guangxi is suitable for large-scale selenium-riched agricultural products development. But strongly soil acidity, high aluminum and iron content and clay, low soil effective selenium in regional selenium-riched of Guangxi, selenium content of agricultural products are often not up to standard, and influence seriously development of selenium-riched product in Guangxi. The project goal is the activation of soil selenium, selenium content of quantitative strengthening agricultural products, Combined the indoor simulation experiment and pot experiment and field experiment, through the analysis of the soil selenium morphological characteristics of Guangxi regional and the law of selenium adsorption and desorption, and its relationship with soil physical and chemical properties and biological properties, looking for selenium effectiveness impact factor; Adopts joint control of inorganic and organic, revealing the selenium activation mechanism of selenium-riched soil in Guangxi region, form a regulation.mode of selenium efficient activation in Guangxi regional selenium-riched soil, as to provide theoretical basis and technical support for quantitative strengthening of crops selenium in Guangxi.

硒有防治疾病、增进健康和减缓衰老等功效，因而富硒产品得到当今越来越重视健康的人们青睐。广西拥有面积达212.1万hm2的连片富硒土壤，适合大规模富硒农产品开发，但广西区域富硒土壤酸度大，粘粒及铁铝含量高，土壤有效硒较低，农产品硒含量常未达标，严重影响广西富硒产品开发。本项目以活化土壤硒素、定量强化农产品硒含量为目标，采用室内模拟试验与盆栽试验田间试验相结合，通过分析广西区域土壤硒素形态特征、硒吸附解吸规律与土壤理化性质和生物性质关系，寻找对硒有效性影响因子；采用有机无机联合调控，揭示广西区域富硒土壤硒活化机理，形成广西区域富硒土壤硒素高效活化的调控模式，为广西作物硒素定量强化提供理论依据和技术支持。

广西拥有适合大规模富硒农产品开发且硒含量较高的连片富硒土壤，但农产品硒含量较低，达不到富硒农产品要求，影响广西富硒产品开发和广西农业发展，其主要原因是广西区域红壤赤红壤中有效硒含量较低，提升土壤有效硒含量是广西富硒农业发展的关键。为此开展广西土壤硒素形态特征及其有效性、富硒土壤硒素转化及有效硒提升的影响因子及土壤硒素活化的调控研究。研究结果表明，广西区域红壤赤红壤总硒含量较高，平均含量分别为0.941mg/kg和1.173mg/kg，有效硒含量均较低，红壤平均占总硒的7.22%，赤红壤平均占总硒的5.52%；土壤对硒的固定较强，其中砂页岩母质土壤对SeO32-固定最强，60天固定达98.10%，而四纪红土和花岗岩母质土壤90天固定率也分别达到69.58%和54.68%；对广西区域土壤有效性硒有显著影响的因子有：交换态硒、硫、磷、富里酸、游离氧化铁铝、非晶质氧化铁、络合态铁铝、粘粒等。采用室内模拟试验研究有机无机因子及生物因子对土壤有效硒提升作用，发现无机因子磷硫钙及有机因子氨基酸、黄腐酸等均能显著提升土壤硒有效性，而从当地土壤中筛选出的两种牙孢杆菌也有较好的活化土壤硒能力；分析土壤硒形态变化发现，有机无机因子主要影响土壤铁锰氧化物结合态硒，而微生物主要影响残渣态硒。有机无机组配试验和生物菌剂组配试验，得到磷和氨基酸组合对硒的活化效果最好，茶叶硒含量可提高40.03%， 生物菌剂J1可显著提高土壤有效硒和增加茶叶硒累积，春茶季土壤有效硒较对照提高236.89%，夏茶季提高39.37%，而春茶和夏茶硒含量分别达到0.34 mg/kg和0.29 mg/kg，比对照提高183.33%和107.14%，茶叶硒含量符合广西富硒农产品标准。形成广西区域富硒土壤硒素高效活化的调控模式，为广西富硒农业发展提供理论依据和技术支持。