Effects Of Polyethylene Film Residue On Yield And Soil Quality Of Spring Maize

Film mulching can improve the environment around crops by regulating the solar radiation and soil hydrothermal state on the soil surface,thus improving crop productivity,water use efficiency and economic benefits.In the context of increasing food demand caused by the world’s growing population,the huge yields and economic returns have made current agricultural production systems highly dependent on plastic mulch.Traditional polyethylene mulching film remains in the soil due to the difficulty of recycling and non-degradability,which changes the soil environment and affects crops to some extent.Therefore,in this study,the effects of plastic film residue on soil quality and crop yield were discussed by returning plastic film residue with different concentrations to the field.The field experiments were carried out in 2020 and 2021 at the Changwu Ecological Experimental Station of THE Chinese Academy of Sciences.A total of six treatments were set up,including a film mulching cultivation（PFM）combined with five film residue gradient treatments,with the film residue of 0,75,150,300,600 kg·hm^-2,and a traditional no-mulching cultivation（CP）with zero film residue treatment.In PFM treatment,furrow and ridge film for rainwater harvesting was used to cover cultivation.The furrow and ridge ratio was 1:1.Only film was covered on the ridge and crops were planted in the furrow.In 2014,the polyethylene film was cut up into residual film fragments with a side length of 5 cm and buried in the topsoil.The main results of the experiment are as follows:（1）Film residue treatment had no significant effect on the growth and yield of spring maize.There were no significant differences in plant height,stem diameter,leaf area and aboveground dry matter accumulation of spring maize under different film residue treatment in each growth and development stage of spring maize.The yield of spring maize under PFM treatment was 10.4 t·hm^-2,which was significantly higher than CP treatment(8.0 t·hm^-2).The yield of spring maize under PFM combined with 75,150,300 and 600 kg·hm^-2 was 10.5,10.6,10.9,respectively.11.2 t·hm^-2.（2）the residual film processing on soil physical and chemical properties were not significantly affected,with the increment of the residual film,nitrate nitrogen,ammonia nitrogen in the soil,organic matter and soluble nitrogen content has a tendency to rise,soil microbial biomass carbon with the increment of the residual film show downward trend after rising first,microbial biomass nitrogen in upward trend after fall first,However,the difference between each residual film treatment did not reach a significant level.（3）There were no significant differences in soil urease,sucrase and catalase under different residual film treatments.With the increase of residual film amount,soil urease and sucrase activities showed a trend of gradual increase.Compared with the non-residual film treatment,soil urease and sucrase activities were increased by 21.15%-25%and 8.44%-9.61%,respectively.Soil catalase activity decreased first and then increased with the increase of residual membrane amount.（4）Residual film had a significant effect on soil microbial community structure,and the microbial community of rhizosphere soil,non-rhizosphere soil and membrane soil was significantly different（P<0.001）.The bacterial and fungal community structure of rhizosphere soil was significantly different under different amount of residual film.The bacterial and fungal community structure of non-rhizosphere soil was significantly different under different amount of residual film.However,there was no significant difference in bacterial and fungal community structure in the intermembrane soil under different amount of residual membrane.The diversity of non-rhizosphere soil fungal community increased with the increase of residual film amount.The Shannon index of residual film treatment was 7.97%-34.42%higher than that of non-residual film treatment.When the residual film amount reached 600 kg·hm^-2,the diversity of non-rhizosphere soil fungal community was significantly higher than that of non-residual film treatment.In conclusion,different film residue treatments had no significant effect on the growth and yield of spring maize.Different residual film treatments had no significant effect on soil physical and chemical properties and enzyme activities.Residual membrane changed the microbial community structure and increased the diversity of microbial community in the adjacent soil.The results of this study indicated that small residual film fragments and low residual mulch amount(≤600 kg·hm^-2)may not harm soil in the short term and have no significant impact on crop yield.