Effects Of Different Film Mulches On Growth Characteristics And Water Use Efficiency Of Summer Maize

China is a country that is seriously short of water.The shortage of water resources has become the main limiting factor that restricts the agricultural production in our country.As an important grain-producing province in China,Shandong province has been more and more seriously affected by drought in recent years.Mulching can effectively retain soil water,reduce evaporation and evapotranspiration,improve soil hydrothermal conditions,promote crop growth,improve crop yield and water use efficiency,and is a "White Revolution" in crop production and cultivation technology.However,with the increasing use of traditional polyethylene plastic film,the "White Revolution" gradually evolved into "White Pollution",and a large amount of polyethylene plastic film residue in the soil caused a series of environmental problems.Compared with traditional polyethylene plastic film,degradable plastic film can not only play the role of increasing temperature and preserving humidity,but also will not cause pollution to the environment after the degradation,which fundamentally solves the problem of polyethylene plastic film residue.This experiment took summer maize,an important food crop in Shandong province,as the research object to explore the differences in the growth and development of summer maize under different mulch,soil moisture temperature changes,summer maize yield and water use efficiency.To clarify the feasibility of biodegradable plastic film replacing traditional polyethylene plastic film,to provide theoretical support for the further promotion and development of biodegradable plastic film,and also to better develop water-saving agriculture,to ease the contradiction between the supply and demand of water resources.There were 4 treatments in total,respectively covering traditional polyethylene film(PF);Cover with degradable white mulch(WF);Cover biodegradable black film(BF);No mulching(CK).The effects of different mulch mulching on the growth characteristics and water use efficiency of summer maize were investigated by two years' experiment in 2018 and 2019.The experiment results show that:Different mulching significantly affected the normal growth and development of summer maize.The chlorophyll content,net photosynthetic rate,transpiration rate and leaf water use efficiency of summer maize treated with traditional polyethylene mulching film and white degradable mulching film were all lower than those treated with no mulching film.Under biodegradable black film mulching,the soil temperature was suitable,which made the indexes of leaf area index and dry matter accumulation of summer maize significantly higher than that of non-mulching treatment.The three mulching treatments increased the volume moisture content of the soil in the 30~60cm soil layer during the summer maize elongation period.Among them,the volume moisture content of the two degradable mulching treatments was lower than that of the traditional polyethylene mulching treatments,but higher than that of the non-mulching treatments.Compared with non-mulching treatment,the total water consumption of summer maize increased by 3.0% after the treatment with black degradable mulching film,while the total water consumption of summer maize treated with traditional polyethylene mulching film and white degradable mulching film significantly decreased by 5.0% and 1.4%.Within 30 days after mulching,the average soil temperature of the soil treated with conventional polyethylene mulching and degradable white mulching was 4~6 ? higher than that of the soil treated with degradable black mulching and non-mulching,and the soil temperature of the treated with degradable black mulching was 0~2 ? higher than that of the no-mulching.After 30 days,as the degradable white film began to degrade,the soil temperature in the treatment also decreased.Under the influence of soil temperature,compared with the non-mulching treatment,the yield of summer maize increased by 28.9% after the treatment with black biodegradable mulching,and that of summer maize decreased by 9.4% after the treatment with traditional polyethylene mulching.The water use efficiency of summer maize increased by 27.5% and 13.1%,and that of traditional polyethylene mulch decreased by 8.9%.The results of this experiment showed that,compared with the traditional nonmulching planting method,the black biodegradable mulching could play a role in saving water and increasing yield in the planting of summer maize in Shandong province,while the yield and water use efficiency were reduced under the conventional mulching method.