| In the last decade,the all filming doulble-furrow thchnology is widely used on uplandcrops cultivation.It has greatly promoted the development of agriculture on dry-land.With the increasing use amount of the plastic mulch,people pay more attention to the risk of soil pollution caused by residual plastic film.In order to have an objective and accurate understanding on the possible effect of plastic film residues on agricultural productivity and sustainability in dry farming,we set the field experiment with different amount of residual plastic film under the semi-arid region of Loess Plateau,Maize and potato are the major crop in the Semi-arid region of Loess Plateau..Field experiments were carried out on maize and potato,Set four levels of film mulching residues,F0: no film mulching(0kg/ha),F10 :continous 10 years film mulching(450kg/ha),F30: continous 30 years film mulching(1350kg/ha),F60: continous 30 years film mulching(2700kg/ha).To investigate 1)the effect of film mulching residues on crop yield,soil quality and soil microbial diversty.we have two experiment field,two series in Potato-Maize and Maize-Potato,the two series are simultaneous.Each treatment has 3 replicates,4 levels of film mulching residues×3 replicates×2 series,there are 24 experimental plots in total.randomized block arrangement.Following is major results of this paper:1.In 2015,the maize yield is3541±459kg/hm2,the aboveground biomass is 5031±477kg/hm2,the potato yield is 4535±332kg/hm2,the aboveground biomass is 1618±102kg/hm2.In 2016,the maize yield is 4290±269kg/hm2,the aboveground biomass is 5458±544kg/hm2,the potato yield is 3241±611kg/hm2,the aboveground biomass is 494±452.4 kgkg/hm2,There was no significant difference between the treatmentsof F0、F10、F30、F60(P﹥0.05);the resultsshowed thatthe plastic film residues have no significant influence on the yield and aboveground biomass of potato and maize2.Soil sample from the corn field in 2015,SOC is3.92±0.4g/kg,TN is 0.45±0.06 m g/kg,AP is 13.29±2.68mg/kg,TP is 0.66±0.02g/kg,Soil sample from the potato field in 2015,SOCis 4.3±0.99g/kg,the TN is 0.42±0.02mg/kg,the AP is 9.74±1.86mg/kg,the TP is 0.61±0.025g/kg.Soil sample from the corn field in 2016,SOC is 4.04±0.48g/kg,the TN is 0.43±0.03mg/kg,the AP is 9.61±2.4mg/kg,the TP is 0.66±0.02g/kg;Soil sample from the potato field in 2015,SOC is 4.16±0.55g/kg,,the TN is 0.66±0.03mg/kg,the AP is 10.5±2.5mg/kg,the TP is 0.66±0.03g/kg,There was no significant difference between the treatmentsof F0、F10、F30、F60(P﹥0.05).The results showed thatthe plastic film residues have no significant influence on soil nutrient and SOC3.Soil sample from the potato and corn fields in 2015 and 2016,the soil water content from 0-200 cm have no significant difference between the treatmentsof F0、F10、F30、F60(P﹥0.05).The results showed that the plastic film residues have no significant influence on soil water content.4.Soil sample from the corn field in 2015,MBC is 36.1±6.94mg/kg,MBN is 8.99±1.62mg/kg,Soil sample from the potato field in 2015,MBC is 30.46±6.92mg/kg,MBN is 8.08±0.65mg/kg;Soil sample from the corn field in 2016,MBC is 23.1±4.17mg/kg,MBN is 9.99±1.03mg/kg,Soil sample from the potato field in 2015,MBC is21.37±3.43mg/kg,MBN is9.99±1.03mg/kg;In two years,There was no significant difference between the treatmentsof F0,F10,F30,F60(P﹥0.05),The results showed that the plastic film residues have no significant influence on soil MBC and MBN.5.Bacteria:for the diversity index Chao and Shannon,the soil sample from F10 F30 F60 compare with the sample from F0,(F10 F30 F60)﹤ F0,P ﹤ 0.05,the difference is significant.Fungi:for the diversity index Chao and Shannon,the soil sample from F10 F30 F60 compare with the sample from F0,there has no significant difference.the results showed that the plastic film residues decreased bacterical diversity,the plastic residues have no significant influence on fungi diversity.6.From the Hierarchical clustering tree of bacteria and fungi we can seen,these samples were devided into two groups,F0,NF10,NF30,NF60 were in one group,F10,F30,F60 were in another group.The community composition of F0,NF10,NF30,NF60 Ishighly similar,The community composition of F10,F30,F60 is highly similar too.The results showed that the plastic film residues have significant influence on community composition of bacteria and fungi.7.the plastic film residues have significanr influence on community composition of bacteria,increase the richness of Pseudomonas,JG30-KF-CM45.reduce the richness of Saccharibacteria,Rubellimicroblum,Acidimicrobiales,TK10.the plastic film residues have significanr influence on community composition of fungi,increase the richness of Mortierella,chaetomiaceae,Sordariomycetes,Monographella,reduce the richness of Gibberella,Nectriaceae,Phoma,Alternaria.In summary,the crop yield had a reducing trend with increasing content of the plastic film residues,but it showed a statistically insignificant.the results showed,The results showed that the plastic film residues have no significant influence on soil nutrient and SOC;the plastic film residues have no significant influence on soil water content;the plastic film residues have no significant influence on soil MBC and MBN.the plastic film residues have no significant influence on fungi and bacteria diversity.Compared with the soil not on the plastic film,the diversity of bacteria have significant decrease. |
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