谷壳灰硅肥改善土壤质量降低水稻镉砷累积的效应

Effect of Silica Fertilizer(Husk Ash)to Improve Soil Quality and Reduce Cd and As Accumulation in Rice

为研究谷壳灰制备硅肥对水稻不同生育期土壤重金属镉(Cd)和砷(As)生物有效性、酶活性、微生物群落结构和糙米重金属含量的影响,开展水稻盆栽试验.结果表明,施用0.1%~1.0%谷壳灰硅肥能提高土壤pH值0.04~0.24个单位,有效硅含量44.2%~97.5%,也能降低土壤有效态Cd含量16.2%~21.4%,有效态As含量16.0%~24.9%;随施加量的增大各生育期土壤酶活性增大,其中蔗糖酶活性显著增大6.3%~145.7%,脱氢酶活性显著增大6.7%~224.1%;分析土壤成熟期微生物群落结构显示,施用谷壳灰硅肥不影响微生物α-多样性,但对微生物β-多样性产生显著影响,促进微生物生长,维持群落结构稳定性;随施加量的增大,糙米Cd含量降低了29.3%~89.7%,糙米总As和无机As含量分别降低7.8%~42.3%和17.2%~44.5%,当施用量在0.5%和1.0%时水稻糙米ω(Cd)<0.2 mg·kg^(-1),ω(无机As)<0.35 mg·kg^(-1).综上,谷壳灰硅肥能改善土壤质量、降低糙米Cd和As含量,具有环境友好性,可用于Cd和As复合污染稻田土壤的治理.

A rice pot experiment was conducted to identify the effect of silica fertilizer prepared from husk ash on the soil bioavailability of cadmium(Cd)and arsenic(As),enzyme activities,microbial community structure,and heavy metal content in brown rice at different growth stages.The results showed that the application of 0.1%-1.0%silica fertilizer-husk ash increased the pH value of soil by 0.04-0.24 units and the content of soil available silicon by 44.2%-97.5%.It also decreased the content of available Cd and available As by 16.2%-21.4%and 16.0%-24.9%,respectively.With the increase in application amount,the soil enzyme activities increased at all growth stages,and the sucrase activity and the dehydrogenase activity significantly increased by 6.3%-145.7%and 6.7%-224.1%,respectively.The analysis of the soil microbial community composition structure at mature stages showed that the application of silica fertilizer-husk ash had no effect on microbialα-diversity,but it had a significant effect on microbialβ-diversity and then promoted microbial growth and maintained the stability of the community structure.With the increase in application amount,the contents of Cd in brown rice decreased by 29.3%-89.7%,and the contents of total As and inorganic As in brown rice decreased by 7.8%-42.3%and 17.2%-44.5%,respectively.Under the application of 0.5%and 1.0%silica fertilizer-husk ash,the Cd contents in brown rice were lower than 0.2 mg·kg^(−1),and the inorganic As contents in brown rice were lower than 0.35 mg·kg^(−1).In conclusion,the silica fertilizer-husk ash can improve soil quality and reduce the contents of Cd and As in brown rice,and it is eco-friendly and can be used to remedy the paddy soil contaminated with Cd and As.