Effects Of Straw And Plastic Film Double Mulch Mode On Soil Micro-ecology And Maize Yield In Coastal Saline-alkali Land

In order to efficiently develop and utilize coastal saline-alkali land,a combination test of straw mulching and plastic film mulching was conducted in coastal saline-alkali land to explore the effects of straw and plastic film mulching mode on soil microecology and maize yield in coastal saline-alkali land.The experiment was carried out in Bohai Grain Barn of Wudi County,Binzhou City from 2019 to 2020.Four treatments were set up,including no mulching(CK),straw mulching(SM),plastic film mulching(PM)and straw mulching + plastic film mulching(SP).This paper studied the distribution of soil water and salt,soil physical and chemical properties,soil enzyme activity,diversity of soil bacterial community and the growth and yield of maize in coastal saline-alkali land,in order to find out the effects of Straw and plastic film double mulch mode on soil microecology and maize yield in coastal saline-alkali land.The test results are as follows:Straw mulching has a continuous salt control effect and plastic film mulching has a continuous water retention effect on the surface soil.The salt content and p H were significantly decreased and the water content was significantly increased in double coated straw membrane treatment.The average water content of 0?20 cm surface layer was SP(25.47 %)>PM((25.16 %)>SM(25.02 %)>CK(24.89 %),and the average salt content of each treatment was CK(2.85 g/kg)>PM(2.81 g/kg)>SM(2.71 g/kg)>SP(2.69 g/kg).After straw mulching,soil organic carbon content was significantly increased compared with plastic film mulching and no mulching(P<0.05).Straw mulching significantly increased the organic carbon content in the 0?20 cm soil layer,but had no significant change in the 20?100cm soil layer.The change of soil total nitrogen and organic carbon showed a similar rule.Soil carbon and nitrogen nutrients were basically stable in 2019 and 2020,and the contents of soil carbon and nitrogen in the surface layer(0?20 cm)were higher than that in the bottom layer(20?100 cm).Straw and plastic film double mulch mode is more conducive to soil carbon and nitrogen accumulation,and helps to improve soil fertility level.The contents of available P and K in the soil surface were increased by double mulching with straw film,and the contents of available P and K increased slightly at the flowering stage.The activities of soil sucrase,soil urease,soil alkaline phosphatase and soil catalase were significantly increased by double coating with straw film.Compared with CK,SM and PM,SP treatment increased sucrase activity by 28.89?41.16 %,16.15?23.37 % and 13.13?15.30 %,respectively.Compared with CK,SM and PM,SP treatment increased urease activity by72.16?75.60 %,15.65?26.07 % and 10.66?41.11 %,respectively.In 2019,the alkaline phosphatase activity of SP treatment increased by 40.81 %,8.42 % and 37.13 %,respectively,compared with CK,SM and PM treatment.In 2020,the activity of PM treatment increased by33.57 %,19.52 % and 1.16 %,respectively,compared with CK,SM and SP treatment.Compared with CK,PM and SP,catalase activity in SM treatment was increased by41.89?51.16 %,25.75?36.36 % and 2.64?5.98 %,respectively.Compared with that in 2019,the activities of four kinds of soil enzymes were increased in 2020.The straw and plastic film double mulch mode increased the richness and diversity of microbial community.CK treatment had the lowest index of Ace,Chao and Sobs,while SP treatment had the highest index of Ace,Chao,Shannon and Sobs.The relationship between the main soil microbial colonies under SP treatment was significantly stronger than that under other treatments,and the number of positive correlation in SP treatment was significantly more than that under other treatments.The responses of the 15 key fungi to water were generally positively correlated,while the responses to salt and p H were negatively correlated.The soil environmental factors that affected the soil microbial community and its functions were mainly carbon and nitrogen system,phosphorus and potassium system and enzyme system.Straw mulching enhanced the stability of carbon and nitrogen system.Straw mulching combined with plastic film mulching could increase corn grain yield.Straw-mulching treatment can inhibit soil layer salt,improve soil physical and chemical properties,increase soil enzyme activity,increase soil microbial diversity,and then improve crop growth environment,improve seedling emergence rate,promote the growth and development of maize plants,and promote the absorption of nutrients by crops.LAI of PM during the whole period of maize growth was significantly lower than that of other treatments.Plant height at jointing and flowering stage under SP treatment was 53.98 % and25.94 % higher than that under PM treatment.The maize plant height under SM treatment was significantly higher than that under PM treatment by 15.87 % and 13.69 % at grain filling and maturity stages.The seedling emergence rate of maize under straw mulching was increased by5.4 %?6.1 % and that under plastic film mulching was decreased by 10.2%?14.8 % compared with that under no mulching.The grain yield was significantly increased by double coating with straw film.In 2019 and 2020,maize grain yield under double mulching with straw film increased by 16.0 %?21.2 % compared with that under no mulching,and the trend was similar in 2020 and 2019.It can be seen that the Straw and plastic film double mulch mode in coastal saline-alkali land is beneficial to reduce soil moisture evaporation,improve soil nutrients,control soil enzyme activity,increase soil microbial diversity,increase maize biomass and yield,and achieve the purpose of controlling alkali and salt,preserving soil moisture and increasing soil yield.The model of Straw and plastic film double mulch can provide theoretical basis and scientific model for the efficient utilization and development of coastal saline-alkali land.