Study On The Preparation And Performance Of Chitosan-based Liquid Mulch Film

Plastic film mulching is of great significance to agricultural production,and can play a role in reducing the use of herbicides,increasing soil temperature,reducing water consumption,accelerating crop growth,and improving crop yield and quality.The extensive use of traditional mulch has caused pollution of soil and water bodies,and even caused environmental and ecological problems such as degradation of agricultural ecosystems.In order to solve the environmental and ecological problems caused by traditional mulch film,the development of green degradable mulch film is imperative.In this study,liquid mulch film was prepared with chitosan as the raw material,and its preparation and properties were studied mainly in the following aspects:1.Various properties of chitosan/polyvinyl alcohol dry film were tested.The results showed that the comprehensive properties of chitosan/polyvinyl alcohol dry film were the best when the ratio of chitosan solution to polyvinyl alcohol solution was 8:2.Under this condition,the properties of chitosan/polyvinyl alcohol dry film were as follows:the tensile strength is 20.44 MPa,the elongation at break is 46.32%,the light transmittance at 400 nm is 84.8%,and the light transmittance at 600 nm is 89.5%,the water vapor transmission rate is 463.85 g/(m~2·d),the water solubility is 15.05%,and the swelling rate is 237.50%.2.Urea,potassium nitrate and boric acid were used as nutrient elements to prepare chitosan-based nutritional liquid mulch film.The effect of nutrient element addition on the water vapor transmission rate of chitosan/polyvinyl alcohol dry film was investigated by orthogonal experiments.It shows that:in the order of significance of urea,potassium nitrate and boric acid additions on membrane water vapor transmission rate,urea>potassium nitrate>boric acid,the interaction term of potassium nitrate and boric acid is more significant;The water vapor transmission rate of the chitosan-based nutritional liquid mulch film prepared when the addition amount of potassium nitrate was 0.62%,the addition amount of potassium nitrate was 0.40%,and the addition amount of boric acid was 0.15%was the lowest,which was 309.05 g/(m~2·d).3.The application performance of the chitosan-based liquid mulch film was studied.The results showed:The chitosan-based liquid mulch film has a good moisturizing effect.The water evaporation of the soil in the sprayed liquid mulch film group within 14 days is 14.74%,which is 4.02%lower than that of the blank experimental group;the chitosan-based liquid mulch film has a certain moisture retention effect.The average temperature at 10 cm of the soil layer sprayed with liquid plastic film within 30 days was 0.974°C higher than the average temperature of the group without liquid plastic film spraying;Compared with the blank control group,the seedling emergence time of No.4 seeds was 1 day earlier,and the seeds of the lettuce seeds,the seeds of sweet and crisp Chinese cabbage 8201 and the seeds of Zhongshu No.4 in the group sprayed with chitosan-based liquid mulch film germinated at the same time.The chitosan-based liquid mulch film can improve the growth and development of crops.After 21 days of spraying the chitosan liquid mulch film,the number of nodes of Yuanfang seedlings in the sprayed liquid mulch film group(two There is a section between the branches)0.23 knots more than the control group,and the average plant height is 2.47cm higher than that of the control group.