原位钝化对轻度镉污染农田小麦修复研究

为探讨原位钝化在镉轻度污染小麦农田上的修复效果,在田间试验条件下,研究了石灰、生物炭配施石灰、生物有机肥配施石灰以及多孔陶瓷纳米材料配施石灰等钝化剂联合修复对镉污染农田中土壤氮、磷、钾含量、土壤pH值、土壤有效态Cd含量、土壤Cd的化学形态、小麦籽粒Cd含量以及小麦产量的影响。结果表明,在土壤Cd背景值为0.337 mg·kg~(-1)的轻度Cd污染农田中,钝化剂处理均可以在不同程度上提高土壤养分含量和pH值,降低小麦籽粒Cd含量和土壤中有效态Cd含量,促使土壤中的Cd形态由易被作物吸收的酸溶态和可还原态转化为不易被吸收的可氧化态和残渣态。其中,小麦籽粒Cd含量降低幅度最大,为40.0%,土壤有效态Cd最大降低率为43.7%,土壤pH值提高0.35。对各指标的相关性分析表明,土壤Cd含量与土壤酸溶态Cd及小麦籽粒Cd含量显著正相关,与可氧化态Cd显著负相关,与可还原态Cd含量极显著正相关;土壤中可还原态Cd与酸溶态Cd含量显著正相关,与小麦籽粒Cd含量极显著正相关。

Study on Rehabilitation of Wheat with Mild Cadmium Pollution by In-situ Passivation

In order to investigate the effect of in-situ passivation on the cadmium-lightly polluted wheat field,under the field test conditions,lime,biochar with lime,bio-organic fertilizer with lime and porous ceramic nano-material with lime were studied. Effects of combined chemical agents on soil nitrogen,phosphorus and potassium contents,soil pH,soil available Cd content,soil Cd chemical form,wheat grain Cd content and wheat yield in cadmium-contaminated farmland were investigated. The results showed that in the mild Cd contaminated farmland with soil Cd background value of 0.337 mg·kg^-1,the passivation treatments could increase soil nutrient content and pH value to different extent,and reduce the Cd content of wheat grain and soil. The Cd content promotes the Cd morphology in the soil from the acid-soluble,and reducible states that are easily absorbed by the crop,compared to the oxidizable and residual states that are not easily absorbed. Among them,the maximum reduction of Cd content in wheat grains was 40.0%,and the maximum reduction rate of soil DTPA-Cd was 43.7%,and the pH value of soil was increased by 0.35. The correlation analysis of each index showed that the soil DTPA-Cd content was positively correlated with soil acid-soluble Cd and wheat grain Cd content,and was negitively correlated with soil oxidizable Cd,and was significantly positively correlated with the reducible state Cd content. There was a significant positive correlation between Cd in reducible state and acid-soluble Cd content and wheat grain Cd content.