Effects Of Plastic Film Mulching And Fertilization On Soil Organic Carbon Mineralization And Crop Yield In Maize-Soybean Intercropping Farmland

The land resources in Guizhou region are relatively scarce,so we are vigorously promoting the intercropping technology of corn and soybean to improve land use efficiency.The changes in soil water and heat conditions after plastic film mulching are beneficial for the growth of dryland crops.In order to increase crop yield,this study explores the effects of plastic film mulching and fertilization on the yield of corn and soybean in Guizhou region.Soil organic carbon has an important impact on soil fertility and greenhouse gas emissions.While exploring the impact of film mulching and fertilization on crop yield,it is important to clarify the changes in soil organic carbon mineralization and soil fertility for maintaining the sustainable development of agricultural ecosystems.Based on this,this study combined field experiments with indoor cultivation,and relied on the Anshun experimental site in Guizhou.Four treatments were set up,including non film mulching without fertilization(non F+CK),non film mulching without fertilization(F+CK),non film mulching with nitrogen and phosphorus fertilizer(non F+NP),and film mulching with nitrogen and phosphorus fertilizer(F+NP).The effects of film mulching and fertilization on soil active organic carbon components,organic carbon mineralization,soil enzyme activity,and corn and soybean yield were analyzed,The main research findings are as follows:(1)Film mulching and fertilization had significant effects on soil Total organic carbon(SOC),microbial biomass carbon(MBC),soluble organic carbon(DOC)and readily oxidizable organic carbon(ROC),and their interaction significantly affected the content of ROC.Mulching reduced the content of SOC,MBC,and ROC,while fertilization increased the content of SOC,MBC,and ROC.Both mulching and fertilization reduced the content of DOC.The content of MBC and ROC gradually increases over time,with a downward trend in DOC and no significant change in SOC.(2)The mineralization rate of soil organic carbon gradually decreases with the extension of cultivation time and finally tends to flatten out,and the accumulated mineralization amount of soil gradually increases.Plastic film mulching and fertilization have a significant impact on soil cumulative mineralization.Compared with non plastic film mulching,plastic film mulching reduces soil cumulative mineralization by 14.3% and 8.9%,respectively,under fertilization and non fertilization conditions;The accumulated mineralization of organic carbon in fertilization treatment was significantly higher than that in non fertilization treatment.Fertilization significantly increased the cumulative mineralization rate of organic carbon,with a significant increase of 19.0% and 22.7% under plastic film mulching and non plastic film mulching conditions,respectively.The mineralization rate of organic carbon under plastic film mulching treatment decreased by 3.0% to 6.3% compared to non plastic film mulching.The cumulative mineralization amount and rate of soil organic carbon are significantly positively correlated with MBC,ROC,and p H.(3)Fertilization increased the content of alkali hydrolyzed nitrogen and available phosphorus,but decreased the content of available potassium.Mulching reduced the content of alkali hydrolyzed nitrogen and available potassium,while increasing the content of available phosphorus;The soil p H gradually increases over time,while the content of total nitrogen,alkaline nitrogen,available phosphorus,and available potassium in the soil gradually decreases.The soil enzyme activity changes significantly over time,with film mulching and fertilization significantly affecting the activities of sucrase,urease,and acid phosphatase,and the interaction between the two is significant;Mulching increased the activity of sucrase and decreased the activity of urease,while the effect of fertilization on both showed different phenomena of inhibition and promotion with or without mulching;Fertilization promotes the increase of acid phosphatase activity,and there are two phenomena of promoting and inhibiting the effect of film covering on acid phosphatase activity;Fertilization can enhance catalase activity,but it is not significantly affected by film covering.(4)The absorption of nitrogen and phosphorus by corn and soybean is significantly affected by film covering and fertilization,and the interaction between the two is significant.Mulching significantly promotes the absorption of nitrogen and phosphorus nutrients by maize and soybean,improving their utilization efficiency of nitrogen and phosphorus fertilizers.However,under no fertilization conditions,the nitrogen and phosphorus nutrient absorption during harvest is reduced,and the crop has the highest nutrient absorption and dry matter quality at each stage under F+NP treatment.The yield of corn and soybean is mainly affected by fertilization factors and the interaction between film mulching and fertilization.Under fertilization conditions,the yield of corn and soybean under film mulching treatment significantly increased by 10.4% and 28.6%,respectively.However,under no fertilization conditions,film mulching can cause a decrease of 30.4% in corn yield;Whether covered with plastic film or not,the yield of corn and soybean under fertilization treatment was significantly higher than that under non fertilization treatment.In summary,plastic film mulching can reduce soil organic carbon,active organic carbon,and soil nutrient content,but it also reduces soil organic carbon mineralization intensity.Combining plastic film mulching and fertilization treatment can effectively promote nutrient absorption and increase yield of corn and soybeans.This plays an important role in reducing soil carbon emissions and improving crop yield.However,timely removal of plastic film and supplementation of soil nutrients should be noted in production,So as to reduce the possible adverse effects of film mulching on soil fertility and crop yield.