Effect of organic acid enhancement on the remediation of cadmium-lead-polluted farmland by feed maize
In order to explore the restoration and improvement of cadmium-lead polluted farmland by forage maize strengthened with organic acid.In this study,a field experiment was conducted to compare the reparative effects and economic benefits of fortified forage maize enhanced with citric acid(CA),tartaric acid(TA),and polyaspartic acid(PASP).The results showed that:all three organic acids could increase the biomass and yield of maize,with a yield increase of 2.92%-8.37%compared to the control.After the application of organic acids,the cadmium and lead concentrations in maize grains ranged from 0.13 mg·kg-1 to 0.90 mg·kg-1 and 0.06 mg·kg-1 to 0.25 mg·kg-1,respectively,which met the national feed hygiene standard(GB 13078-2017)and can be used as plant-based-feed raw materials.Meanwhile,the concentration of cadmium and lead in maize cobs,straw,and roots significantly increased compared to the control,and the ability of straw and roots to accumulate and transport cadmium and lead improved.During the reparation of 0-20 cm of arable soil with TA treatment,Gaoyu 2068 and Jingke 968 extracted the highest amounts of cadmium and lead,respectively,reaching 3.78 mg·m-2 and 48.97 mg·m-2,respectively.In theory,the shortest time required to make the farmland meet the standard for safe use of arable land is 13 years.After the application of organic acids,although the soil pH value during the mature period of maize decreased by 0.09-0.19 units,the highest increase in available cadmium and lead concentration reached 52.37%and 63.22%,respectively,improving the extraction ability of maize plants and thereby reducing the total cadmium and lead concentrations in the soil.From the perspective of economic benefits,under organic acid treatment,the input-output ratio of planting Yufeng 303 is relatively high,ranging from 1.18 to 1.78.This study proves that Gaoyu 2068 has the most significant remediation effect under treatment with TA and PASP.Although the repair period of Yufeng 303 under CA reinforcement is relatively long,it has high economic benefits.Both can be promoted and applied for the simultaneous production and remediation of heavy-metal-contaminated farmland.
organic acidforage maizecadmium and lead pollutionintensive repairfarmland
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