关键词: 生物炭, 养分, 微生物多样性, biolog微平板技术, 连作棉田, 新疆

Abstract: 【Objective】 The objective of this experiment is to explore the effects of biochar application treatment on soil nutrients and microbial diversities in continuous cultivated cotton fields in Xinjiang. The results might provide a scientific basis and practical guidance for optimal utilization of agricultural wastes and prevention of the continuous cultivation problems in cotton fields.【Method】Under the field cultivation conditions, nutrient contents were determined，and traditional microbial cultivation method and Biolog microplate technique were used to study soil microbial communities, the number of physiological bacterial groups and microbial carbon utilization in rhizosphere and non-rhizosphere. Soil nutrients, microbial community characteristics and functional diversities of different biochar treatments were analyzed in grey desert soil and aeolian sandy soil in Shihezi irrigation zone. The experiment designs in grey desert soil were, respectively, biochar+conventional fertilizer (BC+CK) and CK treatments, and biochar application amounts were 22.5 t·hm^-2. The experiment designs in aeolian sandy soil were BC1+CK, BC2+CK and CK treatments, biochar application amounts of 22.5 (BC1) and 45.0 (BC2) t·hm^-2, respectively. 【Result】 Biochar application had influence on pH and nutrients in rhizosphere and non-rhizosphere soils in continuous cultivated cotton fields. Compared with CK, pH of grey desert soils decreased or had no significant difference, that in aeolian sandy soilsincreasedsignificantly. OM of two groups ofgray desert rhizosphere soilsincreased by 36.1% and7.9%, that in non-rhizosphere soilsincreased by 32.8% and15.4%, respectively. OM of aeolian sandy rhizosphere soilswith low and high biochar application increased by 63.6% and295.1%, that in non-rhizosphere soilsincreased by 93.5% and108.8%, respectively.There was no obvious regularity in nutrient contents ofgrey desert soils, available P and available K increased, but available N decreased in aeolian sandy soils. Biochar application increased, the numbers bacteria and fungi in rhizosphere soils in continuous cultivated cotton fields, and the effect in aeolian sandy soil was better than that in grey desert soil. The numbers of soil bacteria in rhizosphere of grey desert soils with biochar application rates increased by 2.2% and 72.1%, respectively, and the numbers of soil fungi increased by 80.0% and 83.3%, respectively. In contrast, the numbers of soil bacteria in rhizosphere in aeolian sandy soils with low and high biochar application rates increased by 16.1% and 35.7%, respectively, and the numbers of soil fungi increased by 300.0% and 300.0%, respectively. Furthermore, the amounts of Cytophaga and Azotobacter were enhanced by biochar application in rhizosphereand non-rhizosphere of grey desert soil, while the amounts of Nitrifier showed a decreasing trend. The amounts of physiological soil bacterial groups were significantly improved in rhizosphereand non-rhizosphere of aeolian sandy soil. Carbon source utilization of soil microbial community showed that soil microbial activities for treatment with biochar application had no significant difference or significantly improved, comparing with the control treatment. However, the effect on soil microbes in rhizosphere of aeolian sandy soil was better than that in non-rhizosphere soil, since theShannon richness index of rhizosphere soilhad a rising trend. 【Conclusion】 Biochar application could improve soil nutrients and microbial diversities in rhizosphere of continuous cultivated cotton fields in Xinjiang, while the soil improvement effect on aeolian sandy soil was better than that on grey desert soil.

Key words: biochar, nutrient, soil microbial diversity, biolog microplate technique, continuous cultivated cotton field, Xinjiang