生物炭对土壤酶活和细菌群落的影响及其作用机制

生物炭因其独特的理化性质能够提高土壤碳氮矿化速率及改善土壤微生态环境,因此探索生物炭调控土壤微生态环境与土壤酶活及其作用机制对改善土壤质量具有重要意义.采用大田试验方式研究不同生物炭施用水平0(CK2)、0.6(T1)、0.9(T2)、1.2(T3)和1.5(T4)t·hm-2以及完全空白对照(CK1:不施任何肥料和生...

Effect of Biochar on Soil Enzyme Activity & the Bacterial Community and Its Mechanism

Biochar-based fertilizers can improve the mineralization of carbon and nitrogen in soil and enhance the soil micro-ecological environment due to particular physical and chemical properties. It is of great significance to explore the underlying mechanism of biochar-based fertilizer in the regulation of soil microorganisms and soil enzyme activity to improve soil quality. Field experiments were conducted to investigate the effects of different biochar-based fertilizer rates[0 (CK2), 0.6 (T1), 0.9 (T2), 1.2 (T3), and 1.5 (T4) t·hm^-2]on soil nutrients, soil enzyme activity, and bacterial community structure. The results showed that with the application of biochar-based fertilizer, soil bulk density decreased, while the pH value, available P, available K, organic matter content, and the C/N ratio increased by 0.32%-5.83%, 14.09%-23.16%, 0%-38.70%, 7.49%-14.16%, and 4.06%-10.13%, respectively, compared to that of the CK2 treatment. With increasing rates of biochar-based fertilizer, the enzyme activity first increased and then decreased. Invertase (INV), urease (URE), catalase (CAT), and neutral phosphatase (NPH) activity under the application of biochar-based fertilizer were 63.73%-166.37%, 117.52%-174.03%, 12.98%-23.59%, and 60.84%-119.71% higher than that of CK2, respectively. The corresponding bacterial diversity was significantly improved, especially with regard to the increase in the abundance of growth promoting bacteria, such as Gemmatimonadetes and Proteobacteria, and decreased the abundance of Acidobacteria and Actinobacteria. The correlation analysis showed that soil C/N ratio was the key factor affecting soil enzyme activity, and there was a significant positive correlation between soil enzyme activity and bacterial diversity. There were significantly positive correlations among the activities of the above four soil enzymes and the relative abundance of Gemmatimonadetes (P<0.01), with CAT being the key factor affecting the bacterial community structure. This study revealed a relationship between soil enzyme activity and microbial colonies, which provides a theoretical basis and mechanism for applying biochar to regulate the soil enzyme and micro-ecological environment.