WANG Xueyu, LIU Jinquan, HU Yun, LI Fahu, WANG Runlian, WANG Xuefeng, LI Ming
To explore the influences of biochar on the bacterial abundance, available nutrient content, and enzyme activity of the rhizosphere soil of cucumber plants, the cucumber plants in heliogreenhouse were studied through different treatments, namely, applying the rhizosphere soil with biochar of 5, 10, 20, 40 t·hm-2 and 60 t·hm-2, respectively. The research results suggested the biochar in the range of 20~60 t·hm-2could significantly enhance the abundances of both lowly and highly evolved bacteria species in the rhizosphere soil of cucumber plants during fruiting period. On family classification level, the biochars in this range improved the abundances of Hyphomicrobiaceae, Rhodospirillaceae, Sphingomonadaceae, Sinobacteraceae, Piscirickettsiaceae, Micromonosporaceae, and Bacillaceae 1, while reduced those of the Gp6, Gp16, and Gp4 families of Acidobacteria; during fruiting period, the biochar promoted the available nutrient content and the activities of urease and sucrose in the rhizosphere soil of cucumber plants by different degrees. The biochar of 20 t·hm-2 therein presented the most significant treatment effect. As compared to the control group, it significantly increased the contents of alkali-hydrolyzable nitrogen, rapidly available phosphorus, and rapidly available potassium, as well as the activities of urease and sucrose by 39.86%, 135.95%, 81.35%, 31.58%, and 52.43%, respectively. In conclusion, biochar application could improve the bacterial abundance, enzyme activity, and available nutrient content in the rhizosphere soil of cucumber plants. The research of the study provided scientific basis and theoretical guidance for the application of biochar in cucumber production.