溶解性有机质强化棉花修复镉污染土壤

Enhanced Remediation of Cd Contaminated Soil by Cotton with DOM

为探究溶解性有机质(DOM)对棉花修复镉(Cd)污染土壤的影响,通过盆栽试验研究棉花秸秆溶解性有机质(CM)和农家肥溶解性有机质(FM)在3种外源Cd(mg·kg^(-1))添加含量为0(C0)、5(C5)和10(C10)下对土壤有效态Cd含量、棉花生物量、光合作用参数和Cd积累的影响.结果表明,CM和FM施入能提高土壤有效态Cd含量,最大增幅分别为30.89%和8.51%,且CM高于FM;CM和FM施入对棉花总生物量和光合作用参数的影响表现为C0水平下促进生物量积累和净光合速率,C5水平下与对照相比无显著差异,C10水平下抑制总生物量积累和净光合速率,但蒸腾速率均呈现出高于同一Cd水平的CK处理;与CK处理相比,施入CM使得棉花各部位(棉纤维除外)Cd含量显著高于同一Cd水平的CK处理,施入FM主要表现在提高根系Cd含量;根系为Cd积累总量增加的主要器官,施加CM和FM均能显著提高棉花的Cd积累总量,增幅范围分别为27.76%~113.05%和17.77%~93.79%.因此,DOM能作为一种添加剂修复Cd污染土壤,具有一定的应用潜力,推荐施用棉花秸秆DOM用于修复Cd污染土壤.

To reveal the effects of dissolved organic matter(DOM)on the remediation of cadmium(Cd)-contaminated soils by cotton,the effects of cotton straw dissolved organic matter(CM)and farmyard manure dissolved organic matter(FM)on soil available Cd(DTPA-Cd)content,cotton biomass,photosynthetic characteristics,and Cd accumulation were investigated in a pot-based experiment under three exogenous soil Cd levels(mg·kg^(-1))of 0(C0),5(C5),and 10(C10).The results showed that the application of CM and FM increased the content of available Cd in soil,with the maximum increase of 30.89%and 8.51%,respectively,and that of CM was higher than that of FM.The effects of CM and FM application on total biomass and photosynthetic characteristics in cotton showed that biomass accumulation and net photosynthetic rate were promoted at the C0 level,there was no significant difference compared to that in the control(CK)at the C5 level,and total biomass accumulation and net photosynthetic rate were inhibited at the C10 level;however,transpiration rate both showed higher than the CK treatment at the same Cd level.The application of DOM altered the Cd content of all parts of the cotton compared to that in the CK treatment,where the application of CM resulted in significantly higher Cd content in all parts of the cotton(except for lint)than that in the CK treatment at the same Cd level;however,the application of FM mainly increased the Cd content in the root.The root was the main organ for the increase in total Cd accumulation,the application of CM and FM significantly increased the total Cd accumulation in cotton,and the total Cd accumulation increased by 27.76%-113.05%and 17.77%-93.79%,respectively.Therefore,DOM can be used as an additive to repair Cd-contaminated soil,which has certain application potential.It is recommended to apply cotton straw DOM to repair Cd-contaminated soil.