| Polyethylene film mulching has alleviated the agricultural water shortage problem in Shandong Province,but there are some environmental problems such as high recycling cost and difficult degradation.Biodegradable film mulching is considered as a reasonable alternative to polyethylene film mulching,but the effects of its long–term film mulching on the growth,water use and environment of summer maize are still inconclusive.In order to explore the feasibility of long–term mulching of biodegradable film,we have carried out a long–term positioning test of film mulching since 2016 and set four different film mulching treatments: transparent polyethylene film mulching(PM),transparent biodegradable film mulching(TM),black biodegradable film mulching(BM)and non–mulching(CK)on soil moisture and environmental conditions,as well as the growth,water consumption,grain yield and water use efficiency of summer maize are analyzed.The main research results are as follows:(1)Biodegradable film mulching contributed to maintaining good soil aggregate structure and had no significant effect on soil organic carbon content,but reduced soil alkali-hydrolyzed nitrogen content in 2022.In the 0-20 cm soil layer in 2022,compared with CK treatment,BM treatment decreased soil alkali-hydrolyzed nitrogen content,neutral phosphatase and catalase activities by 12.51%,17.03% and 12.56% on average,and increased soil available phosphorus content by 3.37% on average.TM treatment decreased soil alkali-hydrolyzed nitrogen,available phosphorus,neutral phosphatase and catalase activities by 11.98%,4.96%,8.12% and18.21% on average,while increased soil urease activity by 42.46% on average.Finally,the SQI value under TM treatment is small,and the difference between BM,PM and CK treatment is not significant.This indicates that black biodegradable film mulching will not have a serious adverse effect on the soil environment.(2)The effects of different film mulching treatments on the growth of summer maize were different at interannual and growth stages,but the biodegradable film mulching treatments could maintain higher leaf area index and net photosynthetic rate in the late growth stage of summer maize,improved the above-ground dry matter accumulation,and ultimately improved the grain yield of summer maize.In the two years,compared with CK treatment,the grain yield of BM treatment and TM treatment increased by 7.24% and 6.29% respectively.Among the two biodegradable film mulching treatments,black biodegradable film mulching treatment had higher summer maize yield.(3)Film mulching can improve soil water storage in the early growth period and reduce farmland water consumption in the whole growth period.Compared with CK treatment,PM treatment decreased water consumption by 5.64% in 2021,TM and PM treatments decreased by 4.21% and 5.64% respectively in 2022.In 2022,the water use efficiency of the three film mulching treatments was improved.compared with CK treatments,BM,TM and PM treatments increased by 7.41%,9.89% and 12.98% respectively.In conclusion,there is no significant difference between BM treatment and PM treatment in maintaining soil environment and ensuring stable and improve grain yield of maize.Black biodegradable film can be used as a reasonable substitute for transparent polyethylene film for agricultural production in Shandong Province. |
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