施用有机物料对土壤中Cu、Cd形态及小麦吸收的影响:田间微区试验

采用田间微区试验研究秸秆与无机肥配施(SM),猪粪与无机肥配施(PM)和无机肥(F)3种不同施肥处理下小麦地不同土层土壤中交换性Cu、Cd的分布状况,以及在小麦不同生长阶段Cu、Cd的动态变化和小麦对重金属Cu、Cd的吸收情况.结果表明,土壤交换性Cu、Cd含量以耕作层(0～20 cm)最高,且随着土层深度的增加含量逐渐降低.随小麦生长,各处理耕层土壤交换性Cu含量均呈下降的趋势,而交换性Cd含量则明显上升.与施无机肥相比,施用有机肥后耕层土壤中交换性Cu、Cd含量明显增加,SM处理交换性Cu、Cd含量平均比F处理高16.7%和43.2%;PM处理Cu、Cd含量分别比F处理高10.6%和17.3% .此外,有机物料的施用还增加了小麦对重金属Cu、Cd的吸收,促进了Cu、Cd在小麦植株内的积累,威胁到食品安全.因此,施用有机物料改良重金属Cu、Cd污染土壤应谨慎.

Influence of applying organic manures on the chemical form of Cu and Cd in the contaminated soil and on wheat uptake:field micro-plot trials

Field micro-plot trials were performed to investigate the dynamics of the exchangeable Cu and Cd in the different depth of the soil amended with straw manure(SM),pig manure(PM),and inorganic fertilizer(F)in different wheat growth period.The uptake of Cu and Cd by wheat was also assessed in this experiment.The results showed that the concentration of exchangeable Cu and Cd was the highest in the depth from 0 to 20 cm and decreased with the depth of soil in three treated soils.Besides,exchangeable Cu decreased and but exchangeable Cd increased in the treated soils with the depth from 0 to 20 cm with the increase of wheat growth time.Compared with the control without the addition of any organic manure(F),two organic manure-treated soils exhibited a higher concentration of exchangeable Cu and Cd.For example,the concentrations of exchangeable Cu and Cd were enhanced by 16.7% and 43.2% in the SM treatment and 10.6% and 17.3% in the PM treatment,respectively,with comparison to the control.The uptake of Cu and Cd by wheat was improved drastically due to the application of organic manures.The obvious accumulation of Cu and Cd in the wheat grain was observed,which might be harmful for food safety.Therefore,it was implied that the application of organic manures to amend the soils contaminated by Cu and Cd should be taken cautiously.