Microplastic distribution is non-homogeneous in agricultural soil following plastic film degradation.However,the distribution of microplastics by shape and particle size in different soil aggregates remains unknown.To...Microplastic distribution is non-homogeneous in agricultural soil following plastic film degradation.However,the distribution of microplastics by shape and particle size in different soil aggregates remains unknown.To elucidate the distribution of microplastic shapes and particle sizes in soil aggregates with increasing years of film mulching,four paired fields with film mulching(FM)and no mulching(NM)were examined at 1,5,10,and 20 years after continuous mulching.An increase in soil aggregates of 0.053–0.25 mm diameter was observed;however,soil organic carbon content decreased after long-term FM.Microplastics primarily combined with 0.053–2 mm soil aggregates.Specifically,long-term FM was associated with dominance of film-and fiber-shaped microplastics in soil aggregates of 0.25–2 mm and 0.053–0.25 mm diameter,respectively.Fiber-and granule-shaped microplastics of 0.25–1 mm diameter primarily combined with 0.053–0.25 and 0.25–2 mm soil aggregates,respectively.Film-shaped microplastics of diameter>1 mm and diameter 0.05–0.25 mm primarily combined with 0.25–2 mm soil aggregates.Therefore,distribution of microplastics in soil aggregates can be used to monitor soil health and quality,greatly enhancing our understanding of the risk posed by microplastics to the environment.展开更多
Microplastics are increasingly recognized as a factor of global change. By altering soil inherentproperties and processes, ripple-on effects on plants and their symbionts can be expected.Additionally, interactions wit...Microplastics are increasingly recognized as a factor of global change. By altering soil inherentproperties and processes, ripple-on effects on plants and their symbionts can be expected.Additionally, interactions with other factors of global change, such as drought, can influence theeffect of microplastics. We designed a greenhouse study to examine effects of polyester microfibers,arbuscular mycorrhizal (AM) fungi and drought on plant, microbial and soil responses. We found thatpolyester microfibers increased the aboveground biomass of Allium cepa under well-watered anddrought conditions, but under drought conditions the AM fungal-only treatment reached the highestbiomass. Colonization with AM fungi increased under microfiber contamination, however, plantbiomass did not increase when both AM fungi and fibers were present. The mean weight diameter ofsoil aggregates increased with AM fungal inoculation overall but decreased when the system wascontaminated with microfibers or drought stressed. Our study adds additional support to themounting evidence that microplastic fibers in soil can affect the plant–soil system by promoting plantgrowth, and favoring key root symbionts, AM fungi. Although soil aggregation is usually positivelyinfluenced by plant roots and AM fungi, and microplastic promotes both, our results show that plasticstill had a negative effect on soil aggregates. Even though there are concerns that microplastic mightinteract with other factors of global change, our study revealed no such effect for drought.展开更多
基金This study was supported by the Ningbo Science and Technology Bureau(2021Z101,2022S103)the National Natural Science Foundation of China(42107341)+2 种基金Scientific Research Projects of the General Administration of Customs(2020HK207)UK Natural Environment Research Council,and Global Challenges Research Fund(NE/V005871/1)the K.C.Wong Magna Fund of Ningbo University.
文摘Microplastic distribution is non-homogeneous in agricultural soil following plastic film degradation.However,the distribution of microplastics by shape and particle size in different soil aggregates remains unknown.To elucidate the distribution of microplastic shapes and particle sizes in soil aggregates with increasing years of film mulching,four paired fields with film mulching(FM)and no mulching(NM)were examined at 1,5,10,and 20 years after continuous mulching.An increase in soil aggregates of 0.053–0.25 mm diameter was observed;however,soil organic carbon content decreased after long-term FM.Microplastics primarily combined with 0.053–2 mm soil aggregates.Specifically,long-term FM was associated with dominance of film-and fiber-shaped microplastics in soil aggregates of 0.25–2 mm and 0.053–0.25 mm diameter,respectively.Fiber-and granule-shaped microplastics of 0.25–1 mm diameter primarily combined with 0.053–0.25 and 0.25–2 mm soil aggregates,respectively.Film-shaped microplastics of diameter>1 mm and diameter 0.05–0.25 mm primarily combined with 0.25–2 mm soil aggregates.Therefore,distribution of microplastics in soil aggregates can be used to monitor soil health and quality,greatly enhancing our understanding of the risk posed by microplastics to the environment.
文摘Microplastics are increasingly recognized as a factor of global change. By altering soil inherentproperties and processes, ripple-on effects on plants and their symbionts can be expected.Additionally, interactions with other factors of global change, such as drought, can influence theeffect of microplastics. We designed a greenhouse study to examine effects of polyester microfibers,arbuscular mycorrhizal (AM) fungi and drought on plant, microbial and soil responses. We found thatpolyester microfibers increased the aboveground biomass of Allium cepa under well-watered anddrought conditions, but under drought conditions the AM fungal-only treatment reached the highestbiomass. Colonization with AM fungi increased under microfiber contamination, however, plantbiomass did not increase when both AM fungi and fibers were present. The mean weight diameter ofsoil aggregates increased with AM fungal inoculation overall but decreased when the system wascontaminated with microfibers or drought stressed. Our study adds additional support to themounting evidence that microplastic fibers in soil can affect the plant–soil system by promoting plantgrowth, and favoring key root symbionts, AM fungi. Although soil aggregation is usually positivelyinfluenced by plant roots and AM fungi, and microplastic promotes both, our results show that plasticstill had a negative effect on soil aggregates. Even though there are concerns that microplastic mightinteract with other factors of global change, our study revealed no such effect for drought.
