微塑料种类、浓度和粒径对黄土区土壤有效磷含量的影响

Effects of type,concentration and particle size of microplastics on soil available phosphorus

化肥和塑料薄膜等化工产品的使用可显著促进粮食生产和土壤肥力改善,但地膜的残留积累不仅影响化肥的有效性,也会给农业环境带来潜在污染和威胁.通过添加不同含量和粒径的传统微塑料(PE、PVC)与生物可降解微塑料(PBS、PLA),分析了土壤中有效磷含量变化特征及其影响因素.结果表明:①传统微塑料与生物可降解微塑料都能显著降低土壤有效磷含量(p<0.05),但生物可降解微塑料对有效磷含量的降低幅度约为传统微塑料的2倍;②随着微塑料浓度的增加,土壤有效磷含量呈先降低后增加趋势,当微塑料浓度达到5%(质量分数)时对土壤有效磷含量的影响最为显著,降低幅度达22.5%~73.6%;③随着微塑料粒径的增大,土壤有效磷含量逐渐升高;④在砂质土壤中,微塑料种类、浓度和粒径变化均未对有效磷含量产生显著影响.微塑料残留量、种类和粒径等性状对有效磷含量的影响因土壤质地不同而存在显著差异.上述结果可为不同土壤条件下微塑料的治理和调控提供参考.

Chemical products,such as chemical fertilizers and plastic films,have significantly promoted food production and soil fertility.However,the legacy of chemical fertilizers and plastic films not only affected soil nutrients supply,but also posed a potential threat to the environmental security.Up to now,effects of microplastic concentration,types and particle size on phosphorus availability in soil are still unclear.Traditional microplastics(PE,PVC)and biodegradable microplastics(PBS,PLA)with different concentrations and particle sizes were added to soil to investigate the variation characteristics of soil available phosphorus and its influencing factors.Both traditional microplastics and biodegradable microplastics significantly decreased soil available phosphorus content(p<0.05),but the reduction of available phosphorus content induced by biodegradable microplastics was twice time as that of traditional microplastics.With the increasing of microplastic concentration,soil available phosphorus content was firstly decreased and then increased,and the highest effect was found in 5%microplastic concentration,which the available phosphorus content decreased by 22.5%~73.6%.While the soil available phosphorus content gradually increased with microplastic particle size increased.However microplastic types,concentrations and particle sizes had no significant effect on available phosphorus in sandy soil.There were significant differences in the effects of microplastic residues,types and particle sizes on available phosphorus content in different texture soils.The results can cast a new light for the impact of microplastics on phosphorus availability in agricultural ecosystems.