Effects Of Biochar And Green Manure On Soil Fertility And Fruit Quality In Pomelo Orchards

The revitalization of the countryside is primarily the revitalization of industry.Jinggang pomelo is one of the three golden signs of the fruit industry in Jiangxi Province and the first of the six characteristic industries that enrich the people in Ji’an City.However,due to unreasonable fertilization and long-term clean cultivation of orchards,soil acidification and compaction in Jinggang pomelo orchards have become serious,which has become an important factor restricting the increase in yield and quality of Jinggang pomelo.It has been reported that the application of biochar and green manure is beneficial to improving soil fertility,improving soil quality,and increasing crop yield,but the effects of biochar and intercropping green manure on soil fertility and fruit quality in Jinggang pomelo orchards are not clear.Therefore,this study takes Jinggang pomelo as the research object,first carries out a field experiment on the type and amount of biochar,designs two types of biochar(rice straw charcoal JG,rice husk charcoal DK),3 application rates(3,6,9 kg/plant)totaling 7treatments(CK,JG1,JG2,JG3,DK1,DK2,DK3);clarifies the effects of different types and amounts of biochar on soil fertility and fruit quality in Jinggang pomelo orchards;at the same time,carries out a field experiment on green manure(white clover)and biochar application,designs clean cultivation(CK),intercropping white clover with rice straw charcoal(T1),intercropping white clover with rice husk charcoal(T2),intercropping white clover(T3)4 treatments to explore the effects of different types of biochar application and green manure intercropping on soil fertility and fruit quality in Jinggang pomelo orchards.Finally,clarify the cultivation management technology of green manure white clover and biochar application to provide theoretical support for the healthy development of Jinggang pomelo industry.The main research results are as follows:(1)The application of different types and amounts of biochar in pomelo orchards can improve soil physical and chemical properties and increase soil nutrient content.When the application rate is the same,the effect of rice straw charcoal on soil improvement is better than that of rice husk charcoal.Among all treatments,the treatment with 9kg/plant of rice straw charcoal had the best effect,and the p H value of soil in the 40-60 cm soil layer increased by 10.61%.Within the range of 0-9 kg/plant,as the amount of biochar applied increased,soil bulk density decreased,and soil p H,organic matter,alkali-hydrolyzed nitrogen,available phosphorus,available potassium,and total nitrogen content increased.(2)The application of different types and amounts of biochar in pomelo orchards can increase the number of soil microorganisms.Within the range of 0-9 kg/plant,the number of soil bacteria,fungi,and actinomycetes showed a trend of first increasing and then decreasing.Among all treatments,the JG2 treatment had the highest number of soil bacteria,which was2.03 times that of the CK treatment;the DK2 treatment had the highest number of fungi and actinomycetes,which was 1.54 and 2.21 times that of the CK treatment.(3)The application of different types and amounts of biochar in pomelo orchards can improve the yield and fruit quality of pomelo.Generally speaking,when the application rate is the same,the effect of rice straw charcoal treatment on improving the yield and fruit quality of pomelo is better than that of rice husk charcoal treatment.Among all treatments,the JG2 treatment had the highest yield of pomelo,and the DK2 treatment had the highest single fruit weight of pomelo.The yield of pomelo in the JG2 treatment increased by 39.15%.Within the range of 0-9 kg/plant,as the amount of biochar applied increased,the soluble solids,vitamin C,and total sugar content of pomelo fruit increased,and titratable acid content decreased with increasing application rate.(4)Intercropping white clover and intercropping white clover with biochar in pomelo orchards can improve soil environment,improve soil structure,and increase soil nutrient content.The overall performance is T1>T2>T3>CK.The surface soil temperature in August in T1 treatment decreased by 16.45% compared to CK treatment.In August and September,the soil moisture content in T1 treatment increased by 44.81% and 46.77%,respectively.Compared with T3 treatment,T1 and T2 treatments can increase soil organic matter,nitrogen,available phosphorus,and available potassium content,and increase soil macro-aggregate content.(5)Intercropping white clover and intercropping white clover with biochar in pomelo orchards can increase the number and activity of soil microorganisms and significantly increase soil bacterial diversity.Compared with T3 treatment,T1 and T2 treatments increased the number and activity of soil microorganisms and enzymes.The number of soil bacteria in T1 treatment was higher than that in T2 treatment,and the activity of urease and sucrase was also higher than that in T2 treatment.The activity of urease in soil in T1 treatment was 2.07 times that of CK treatment and 1.54 times that of T3 treatment.The soil bacterial diversity in T2 treatment was better than that in T1 treatment.(6)Intercropping white clover and intercropping white clover with biochar can improve the yield and quality of pomelo.All treatments of T1,T2,and T3 significantly improved the fruit shape index,soluble solids,juice yield,edible rate,solid-acid ratio,increased vitamin C,total sugar content and yield,reduced titratable acid content,and the overall effect of improving fruit quality and yield was T1>T2>T3.Compared with CK,the yields of T1,T2,and T3 treatments increased by 10.72%,10.88%,and 7.34%,respectively,and the soluble solids content increased by 11.80%,10.39%,and 8.99%,respectively;compared with T3 treatment,the titratable acid content of pomelo fruit in T1 treatment decreased significantly by 16.40%,and the solid-acid ratio of pomelo fruit in T1 treatment was significantly higher than that in T3 treatment.