Comparative Study Of Different Mulch Films Environment Effects And Costs Based On LCA

Modern agriculture depends heavily on the use of mulch film.Mulch film can increase soil temperature,soil moisture,improving soil environment,and provide a good growth environment for plant growth.With the increase of the amount of traditional plastic mulch film,the plastic mulch film remaining in the soil is broken and piled up in the soil due to its non-degradability,which seriously damages the soil quality and affects the safety of agricultural production.Therefore,the research on environmentally friendly degradable mulch film has become a research hot spot.In this study,the life cycle assessment method was used to evaluate the environmental impact of five kinds of mulch films manufacturing processes:straw fiber-based mulch film,recyclable HDPE mulch film,LLDPE mulch film,starch-based mulch film and cellulose nanofiber composite straw fiber-based mulch film.The differences between the mulch films were analyzed,and the optimization direction of mulching film was explored.The life cycle list of five kinds of mulch films was established by collecting the data of production process,use and waste of five kinds of mulch films.Combined with the LCA method of ECER comprehensive index,the environmental impact of five kinds of mulch films was evaluated respectively,and 16 environmental impact indexes in ISO were calculated.The economic cost of five kinds of mulch films was evaluated by using the life cycle cost method.The environmental impact and life cycle cost of straw fiber-based mulch film and other mulch films were compared and analyzed.The research results of life cycle evaluation of mulch films are as follows:（1）Based on the results of environmental impact life cycle assessment,the global warming potential（GWP）,primary energy deplete consumption value（PED）and water use resource consumption value（WU）of straw fiber-based mulch film products are 1.26E+02 kg CO₂eq,4.82E+02 MJ and 9.10E+02 kg,and the eutrophication potential（EP）is 1.52E+00 kg PO₄^3-eq,and real inhalable inorganic matter（RI）is-3.58E+00 kg PM2.5 eq.The greenhouse gas potential value of straw fiber-based mulch film is relatively small in its life cycle,but the consumption of primary energy and water resources is higher than that of LLDPE mulch film and starch-based mulch film.The eutrophication potential is low,the emission of inhalable particulate matter is negative,and the comprehensive index evaluation results are good.In the life cycle results,LLDPE mulch film has a significant impact on the environment.（2）In the production stage,the environmental impact of straw fiber-based mulch film is higher than that of LLDPE mulch film and starch-based mulch film.However,the environmental impact of production unit quality is far lower than that of unbleached kraft paper with similar properties.The raw material of straw fiber-based mulch film is low-value agricultural and pastoral waste straw,which reduces the environmental emissions from raw materials.According to the sensitivity analysis results of different mulch film production stages and the comprehensive index value of ECER,the priority of the improved process was identified.The pulping process of straw fiber-based mulch film had the highest sensitivity,and the comprehensive index value of sensitivity was±7.22E-12.Choosing a beater with lower energy consumption and using a cleaner power source can effectively reduce the environmental impact and achieve low energy consumption production instead.（3）According to the calculated environmental impact characterization results of production and waste stages in the life cycle of mulch films,the global warming potential of straw fiber-based mulch film can be reduced by 1.01E+03 kg CO₂eq,occupying 8%of the total mulch film production,and avoiding 3.93 kg of total particulate matter generated by burning,resulting in its reverse growth of 68.36 times of production emissions.The results show that straw fiber-based mulch film and starch-based mulch film have little environmental impact,which proves the environmental protection performance of degradable mulch film when it is abandoned.This research result can be directly applied as the background data of agricultural production research,which can avoid the increase of data uncertainty caused by different usage scenarios,prevent the decrease of data representativeness,and increase the universality of research results.（4）According to the calculation of the life cycle cost of different mulch films,the result shows that the straw fiber-based mulch film is about 711.52 yuan/ha,and its internal production cost is higher,reaching 98.44%（700.43 yuan）of the life cycle cost.The lowest price is about610.98 yuan/ha,which is higher than that of LLDPE mulch film,but it will produce higher external environmental impact,accounting for 76.86%（269.88 yuan）In comparison,the cost of straw fiber-based mulch film is lower than that of starch-based mulch film,recyclable high-density polyethylene mulch film and cellulose nanofiber composite straw fiber-based mulch film,but its life cycle cost is still higher than that of linear low-density polyethylene mulch film.The production process can be optimized by improving the machinery used in the production process to reduce the power consumption of the production process to achieve low energy consumption,thus further reducing the environmental impact and production cost.