外源硫输入对稻田土壤硒流失的影响

土壤中硒的甲基化可能会导致硒的挥发,加剧土壤硒的流失,而农田土壤硒的缺乏会造成农作物中硒含量偏低.施用硫肥是保障作物增产、增收的一种重要农艺措施,外源硫输入对土壤硒的含量可能产生重要的调控作用.本研究模拟稻田淹水环境,通过添加典型有机硫(甲硫氨酸)和无机硫(硫酸钠),测定硒的挥发量以及土壤中残留的硒含量,以揭示外源硫输...

Effects of exogenous sulfur input on selenium loss in paddy soils

Selenium methylation can promote the production of volatile organic selenium,which could lead to selenium loss in soils,and subsequently result in lower selenium levels in crops.Considering that applying sulfur fertilizers for a high and stable yield in crop production is common in agricultural activities,the input of exogenous sulfur may play a key role in regulating the forms or contents of selenium in soils.To explore the migration and transformation of selenium in response to the exogenous sulfur input,we simulated flooded paddy soil environment,added organic sulfur(i.e.,methionine)and inorganic sulfur(i.e.,sodium sulfate)in paddy soils under an anaerobic and dark condition,and determined the volatilization of selenium and residual selenium content in soils.Our results indicate that the input of both inorganic and organic sulfur promoted the loss of selenium in paddy soils.Compared with the blank control group,methionine input enhanced a decrease in residual selenium content of 15.9%-35.7%,because selenium methylation provided large numbers of methyl donors,leading to an increase in selenium volatilization of 88.4%-308%.While sulfate input could promote the dissolution of selenite in soils,resulting in a reduction of 4.67%-25.5%in residual selenium content.Hence,selenium loss induced by sulfur input should be taken into consideration when applying sulfur fertilizers in in farmland soil.