Study On Improvement Effect Of Biochar/Vinegar Substrate On Acidified And Salinized Soil Of Facility Vegetables

In recent years,protected vegetables have developed rapidly and have become an important part of facility agriculture in China.However,due to unscientific fertilization and management,soil acidification and salinization of protected vegetables are widespread,which has become one of the most prominent problem under greenhouse cultivation and production in southern China,and also a major factor in the continuous cropping obstacle of vegetables.Therefore,improving acidification and salinization soil has an important significance for the sustainable development of protected vegetables.In this study,lettuce was used as a test material to study the effects of biochar substrate on the physical and chemical properties of the acidified and salinized soil,and growth of lettuce in a potted manner.The suitable for acidified and salinized soil of biochar types and their dosages were screened.On this basis,the biochar and vinegar grains were mixed with the soil in proportion to study the physical and chemical properties of the biochar and vinegar grains on acidification and salinization,soil enzyme activities,and growth,photosynthesis,yield and quality of lettuce.The effect and application of acidification and salinized soil in biochar and vinegar mixture improvement facilities are clarified,which laying a theoretical foundation for the research and development of soil substrate conditioner for facility vegetable continuous cropping obstacles.The main results are as follows:1.The three biochar substrates of rice husk charcoal,rice straw charcoal and corncob carbon were mixed with acidified and salinized soil(mass ratio,w/w)at 1%,2%,3%,4%and 5%respectively.To study the effects of biochar types and dosages on the physical and chemical properties of acidified and salinized soils and the growth of lettuce.The results showed that addition of biochar could reduce the EC value and bulk density of the acidified and salinized soil in different degrees,and increased the pH and total porosity of the soil.The treatment with B4(adding 4%rice straw charcoal to the soil)was the most notable.The Venting pores treated by B4 increased by 510.94%compared with the control,the pH of the acidified and salinized soil increased by 1.34 units,the EC value decreased by 43.39%,the plant height,stem diameter,fresh shoot weight and dry root weight.The fresh weight of the ministry and dry weight of the underground increased by 63.27%,157.73%,175.53%,297.62%,545.83%and 371.43%,respectively.Compared with the control,the chlorophyll a and total chlorophyll content of lettuce increased under B4 treatment by 81.81%and 92.86%,respectively.These results indicate that the addition of 4%rice straw charcoal could improve the physical and chemical properties of acidified and salinized soil and promote lettuce growth under protected cultivation conditions.2.On the basis of screening the rice straw charcoal suitable for acidification and salinized soil improvement,mix the rice straw charcoal with the vinegar grains in proportion(w/w)to form a matrix conditioner,and then the matrix conditioner(4%).Adding to acidified and salinized soil,the effects of different proportions of matrix conditioners on the physical and chemical properties,organic matter content,soil enzyme activity and microbes of acidified and salinized soils were studied.The results showed that both rice straw charcoal and vinegar grain conditioners increased the pH of acidified and salinized soils,and significantly decreased the EC value.The T5 treatment increased the pH by 8.30%compared with the control,while the EC value decreased 22.38%.T5 treatment increased the activities of catalase,sucrase and urease in acidified and salinized soil by 20.24%,242.41%and 75.73%,respectively.At the same time,T5 treatment significantly increased the number of bacteria and actinomycetes and decreased the number of fungi in the soil.These results indicate that rice straw charcoal and vinegar grains conditioner have obvious effects on the physical and chemical properties of acidified and salinized soil,and can regulate the number of microorganisms in the soil.Through the effect of lettuce cultivation test,rice straw charcoal and vinegar grain matrix conditioner can improve the root activity of lettuce.After 30 days of colonization,the net photosynthetic rate(Pn)of T5 treated with lettuce increased by 119.61%compared with the control,the Vc content of lettuce increased by 82.32%,the soluble sugar content increased by 49.89%,and the nitrate content decreased by 26.62%.Different ratios of rice straw charcoal and vinegar grain conditioners(T1?T9)can increase the yield of lettuce,while T5 treatment can increase the yield of lettuce by 64.82%.These results indicate that the application of rice straw charcoal and vinegar grains in acidified and salinized soils can promote the growth and quality of lettuce.The above research results show that the application of rice straw charcoal and vinegar residue matrix can improve the physical and chemical properties of acidified and salinized soil,reduce soil acidification and salinization,increase soil enzyme activity and microbial population,Thereby promoting the absorption and utilization of nutrients by lettuce,which is conducive to the growth and development of lettuce and the improvement of yield and quality.Comprehensive soil physical and chemical properties and crop growth,the improvement effect of T5 treatment(rice straw charcoal:vinegar:soil=1:1:50,mass ratio)is the most obvious,can be as an improvement matrix conditioning agent for acidification and salinized soil of protected vegetables.