关键词: 连作棉花, 棉秆炭, 生物有机肥, 根际土壤微生态, 棉花长势

Abstract: In order to research the prevention and control effects of cotton stalk biochar combined with bio-organic fertilizer on obstacles of continuous cropping cotton, the typical continuous cropping cotton soil was selected for pot experiment, and four treatments, including no cotton stalk biochar and bio-organic fertilizer additions (CK), cotton stalk biochar addition (T1), bio-organic fertilizer addition (T2), cotton stalk biochar and bio-organic fertilizer additions (T3), were carried out. The effects of different treatments on rhizosphere soil nutrient, microbial quantities, microbial functional diversity and quantity of pathogenic fungi, cotton growth and  protective enzymes activities were analyzed by conventional methods, Biolog Eco-microplates and high-throughput sequencing. The results showed that cotton stalk biochar, bio-organic fertilizer and their combined application could significantly increase nutrient contents and culturable microbial quantities in rhizosphere soil of continuous cropping cotton. Cotton stalk biochar combined with bio-organic fertilizer treatment (T3) was the best treatment. Compared to CK, the contents of organic matter, available phosphorus and available potassium in T3 treatment significantly increased by 46.09%, 19.71% and 144.75%, respectively. The quantities of bacteria, actinomycetes and fungi in T3 treatment significantly increased by 62.32%、63.46% and 11.74%, respectively. Biolog carbon resources utilization analysis showed that T3 treatment did not significantly increase the utilization of carbon sources. However it increased soil microbial functional diversity, and there were obvious differences among different treatments. Carbohydrate and amino acids were the main carbon sources that determined the differentiation of principal components. The result of high throughput sequencing showed that T3 treatment significantly reduced the quantity of pathogenic fungi Fusarium. Cotton stalk biochar, bio-organic fertilizer and their combined application could significantly promote cotton growth, and the effect of T3 treatment was the best. Compared to CK treatment, the plant height, stem diameter and root length increased significantly by 18.24%、13.89% and 14.53%, polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL) activities of cotton leaves significantly increased by 116.28% and 182.55%. Compared with conventional fertilization, the combination of cotton stalk biochar and bio-organic fertilizer was considered to be able to improve rhizosphere soil micro-ecology environment of continuous cropping cotton fields, and promote cotton growth and protective enzyme activities. The present research would provide theoretical basis for scientific, efficient utilization of cotton stalk and healthy, sustainable development of cotton industry.

Key words: continuous cropping cotton, cotton stalk carbon, bio-organic fertilizer, rhizosphere soil micro-ecology, cotton growth