Study On Preparation Of Vegetable Straw Biochar And Its Effect On Improving Continuously Cropped Soil Of Cucumber

With the expansion of vegetable planting area,vegetable straw waste increases,causing environmental pollution.As a soil conditioner,crop straw biochar has the effect of improving soil physicochemical properties,increasing soil nutrient content and microbial diversity,and promoting crop growth,but there are few research reports on the preparation and application of vegetable straw biochar.In this paper,using tomato,bell pepper and eggplant straw as experimental materials,the effect of pyrolysis parameters on biochar properties was studied,and the improvement effect of greenhouse cucumber continuous cropping soil was proved,in order to provide theoretical and technical basis for the resource utilization of vegetable straw and the improvement of facility soil.The main results are as follows:1.A regression equation is established with the independent variable of pyrolysis temperature and pyrolysis time,and the comprehensive score of biochar properties as the dependent variable.The analysis shows that: The effect of pyrolysis temperature on the biochar properties of tomato and eggplant straw is greater than that of pyrolysis time,the effect of pyrolysis time on the biochar properties of bell pepper straw is greater than that of pyrolysis temperature;The optimal pyrolysis temperature and pyrolysis time for the preparation of biochar from tomato,bell pepper and eggplant straw were 365℃/104 min,489℃/95 min,and 347℃/83 min.The p H,EC value and potassium content of bell pepper straw biochar were higher;Tomato straw biochar has a good pore structure,high methylene blue adsorption rate and iodine adsorption capacity,nitrogen and phosphorus content is also very high;The amount of cation exchange in eggplant straw biochar was higher.2.All three kinds of vegetable straw biochar can increase the soil pH and EC of greenhouse cucumber continuous cropping,increase the content of soil organic matter,alkaline nitrogen,available phosphorus and available potassium,and the effect is more obvious with the increase of biochar consumption;Soil sucrase,catalase,urease and Shannon index,Ace index and Chao index all increased and then decreased with the increase of biochar consumption,which increased the relative abundance of Actinobacteriota,Proteobacteria,Olpidiomycota and Rozellomycota.At the same dosage,the effect of bell pepper straw biochar on increasing the soil nutrient content,soil enzyme activity and soil microbial diversity of cucumber continuous cropping was the most obvious.3.The plant height,stem diameter,leaf area,dry matter weight,root activity,leaf pigment content,net photosynthetic rate and antioxidant enzyme activity of continuous cropping cucumber could be increased by applying appropriate amount of vegetable straw biochar.Tomato straw biochar dosage of 2.5%,bell pepper and eggplant straw biochar 5% of the effect is the best.In a comprehensive comparison of different straw biochar types and dosages,the 5% dosage of bell pepper straw biochar was the most obvious in promoting the growth of continuous crop cucumbers.