摘要
本研究以镉污染石灰性土壤(Cd含量7.15 mg/kg)为基质进行盆栽试验,设置Cd胁迫下施用不同热解温度生物炭(250、480℃,B1、B2)、柠檬酸不同用量(1、10 mmol/kg,N1、N2)及其组合处理(B1N1、B1N2、B2N1、B2N2),以单种植紫花苜蓿为对照(CK),研究不同热解生物炭和柠檬酸用量对土壤性质、Cd形态转化及紫花苜蓿Cd富集的影响。结果表明,生物炭、柠檬酸处理皆可提高土壤有效养分含量、提高土壤酶活性、改变低分子量有机酸组成,高温热解生物炭、高剂量柠檬酸处理效果更显著。生物炭、柠檬酸处理影响土壤Cd形态转化和紫花苜蓿Cd的富集,但二者的作用强弱与机制不同;不同热解温度生物炭对Cd皆为吸附钝化效果,而低浓度柠檬酸略微钝化Cd,高浓度柠檬酸活化土壤碳酸盐结合态镉(CA-Cd)和可交换态镉(EX-Cd),提高有效Cd含量。生物炭与柠檬酸配施条件下,与CK相比,B1N2处理的土壤有效Cd含量、植株Cd含量及生物富集系数分别显著提高40.01%、57.48%及12.40%,B2N1则分别显著下降26.79%、49.38%及30.81%。综上,不同热解温度生物炭及柠檬酸剂量对Cd修复的作用强弱与机制存在差异,高温生物炭配施低剂量柠檬酸可钝化土壤Cd,低温生物炭配施高剂量柠檬酸处理可活化土壤Cd及促进紫花苜蓿Cd富集。
A pot experiment was conducted with cadmium(Cd)contaminated soil(7.15 mg/kg Cd)as substrate,and biochar prepared by different pyrolysis temperature(250 and 480℃)(B1 and B2),different dosage(1 and 10 mmol/kg)of citric acid(N1 and N2)and their combinations(B1N1,B1N2,B2N1,B2N2)were set with only planting alfalfa as control(CK).Their effects on soil properties,Cd form transformation and Cd accumulation in alfalfa were studied.The results showed that both biochar and citric acid treatments could increase the content of soil available nutrients and the soil enzyme activities,and change the composition of low molecular weight organic acids,and the effects of high-temperature pyrolysis biochar and high-dose citric acid treatment were more significant.Biochar and citric acid treatments affected the transformation of Cd form in soil and the enrichment of Cd in alfalfa,but their effect level and mechanism were different.The biochar with different pyrolysis temperatures had the adsorption passivation effect on Cd,while low concentration of citric acid had slight passivation effect on Cd,and high concentration of citric acid activated soil carbonate-bound Cd(CA-Cd)and exchangeable Cd(EX-Cd)to increase the effective Cd content.Under the combined application of biochar and citric acid,compared with CK,the soil available Cd content,plant Cd content and bioconcentration factor of B1N2 treatment were significantly increased by 40.01%,57.48%and 12.40%respectively,while those of B2N1 were significantly decreased by 26.79%,49.38%and 30.81%respectively.In summary,the effect level and mechanisms of biochar prepared by different pyrolysis temperatures and different doses of citric acid on Cd remediation were different.High-temperature biochar combined with low-dosage citric acid could passivate soil Cd,while low-temperature biochar combined with high-dosage citric acid could activate soil Cd and promote the Cd enrichment in alfalfa.
作者
张伟华
张伟丽
周晶
Zhang Weihua;Zhang Weili;Zhou Jing(College of Life Sciences and Engineering,Jining University,Jining 272113,China;Hekou District Secondary Vocational School of Dongying City,Dongying 257200,China;College of Life Sciences,Qufu Normal University,Qufu 273165,China)
出处
《山东农业科学》
北大核心
2024年第10期119-126,共8页
Shandong Agricultural Sciences
基金
国家自然科学基金青年科学基金项目(41807053)。
关键词
生物炭
柠檬酸
紫花苜蓿
土壤酶活性
镉污染土壤
镉形态
生物富集系数
Biochar
Citric acid
Alfalfa
Soil enzyme activity
Cadmium contaminated soil
Cadmium form
Bioconcentration factor
