牛粪有机肥与化肥配施对土壤重金属形态的影响

Effect of Organic Cattle Manure and Chemical Fertilizer Application on Heavy Metal Morphology in Soil

为缓解畜牧业产能的提高和日益严峻的畜禽粪污污染之间的矛盾,充分挖掘畜禽粪污肥料化利用的潜力,避免过量施用对环境带来的潜在重金属危害,本试验采用牛粪有机肥为研究对象进行盆栽试验,根据牛粪有机肥和化肥的不同配施比例,设置5个处理,测定收获后不同处理土壤中重金属铜、锌各形态质量分数,并进行土壤有机碳和pH的测定。结果表明,与CK组相比,配施牛粪有机肥可以降低土壤中重金属Cu、Zn的总质量分数,DF1处理组降低幅度最大,分别下降了25.54%、39.20%;与CK组相比,DF1和DF2处理组可交换态Cu分配率从15.86%分别提高至28.13%、42.02%,促进残渣态向可交换态转化,DF2处理组对分配率的提高幅度最大;与CK组相比,CD和DF1处理组残渣态Zn分配率分别降低至39.27%、38.40%,DF2处理组变化幅度最大,降低至24.33%。配施牛粪有机肥后,土壤pH、有机碳含量有上升趋势,其中土壤有机碳与土壤中有效态铜、锌的分配率变化趋势呈正相关,相关性显著(P<0.05),同时土壤有效态锌与土壤pH的变化趋势呈正相关,相关性显著(P<0.05),但重金属铜的有效态与pH的相关性不显著(P>0.05)。施用牛粪有机肥时应严格遵循测土配方算出的实际需求量,避免过量施用,增加土壤环境的重金属污染风险。

The purpose of the study was to alleviate the contradiction between the increase of livestock production capacity and the increasingly serious pollution of livestock manure,to explore the potential of fertilizer utilization of livestock manure and avoid the potential heavy metal hazards to the environment caused by excessive application.The experiment used organic fertilizer made of cow dung as the research object for pot experiment,and five treatments were set up according to different proportions of organic fertilizer made of cow manure and chemical fertilizer application,and the mass fraction of each form of heavy metal Cu and Zn in the soil of different treatments after harvesting was determined,the determination of soil organic carbon and pH value was also performed.The results showed that the distribution of cow dung organic fertilizer could reduce the total mass fraction of heavy metals Cu and Zn in the soil,and the DF1 treatment had the greatest reduction,which was 25.54%and 39.20%,respectively,compared with the CK treatment.Meanwhile,it promoted the transformation of residue state to exchangeable state,the distribution rate of the exchangeable state Cu in DF1 and DF2 treatments increased form 15.86%to 28.13%and 42.02%,respectively,compared with CK treatment,and DF2 treatment had the greatest increase on the distribution rate.Zn distribution rate of residue state was reduced to 39.27%and 38.40%,respectively,in CD and DF1 treatments,compared with CK treatment.The change in DF2 treatment was the greatest,from 53.40%to 24.33%.After the application of cow dung organic fertilizer,the soil pH and organic carbon content had a tendency to increase,in which the soil organic carbon was positively correlated with the trend of the allocation rate of the effective state of Cu and Zn in the soil,and the correlation was significant(P<0.05),while the positive correlation between the soil effective state of Zn and the trend of the soil pH was significant(P<0.05),but the correlation of the effective state of the heavy metal Cu and the pH was not significant(P>0.05).To sum up,the application of organic fertilizer made of cattle manure should strictly follow the actual demand calculated by soil testing formula to avoid excessive application which increases the risk of heavy metal pollution in the soil environment.