College of Resources, Sichuan Agricultural University
Supported by the Applied Basic Research Program of Sichuan Province, China (No. 2021YJ0259), the Scientific Research Interest Training Plan of Sichuan Agricultural University, China (No. 2020346), the Science and Technology Inovation (Miaozi Project) Cultivation and Small Invention and Small Creation Project of Sichuan Province, China (No.2021094)
为探究生物质炭负载解钾菌对土壤微生物特性的影响，基于5个处理即空白（CK）、施用化学钾肥（KCl）、接种解钾菌（KSB）、施用生物质炭（BC）、施用生物质炭负载解钾菌（BC-KSB）的黑麦草盆栽耗竭试验，分析不同处理下土壤酶和微生物群落结构的响应特征。结果表明，BC-KSB相比其余施肥处理更有利于提高土壤脲酶、蔗糖酶、酸性磷酸酶和过氧化氢酶的活性，同时也提高了土壤细菌的物种多样性与菌群丰富度，并提高了土壤有益菌群（绿弯菌门、放线菌门、芽孢杆菌属和慢生根瘤菌属）的丰度，抑制了土壤致病菌群（变形菌门和罗河杆菌属）的繁殖。各施肥处理相比CK均显著提升了黑麦草干物质量，且以BC-KSB处理对黑麦草干物质量的提升最为显著。与CK和KCl相比，BC-KSB能显著提高土壤微生物生物量碳、微生物生物量氮、有机质、全氮和速效钾的含量（P < 0.05）。冗余分析表明，土壤有机质、速效钾、酸性磷酸酶、脲酶和微生物生物量氮是影响细菌群落结构的主要因子，黑麦草的生长主要受伯克氏菌属和罗河杆菌属的影响较大。可见，BC-KSB对黑麦草产量、土壤养分、土壤酶活性和细菌群落结构均产生了积极的影响，对于改良土壤生态环境具有良好的效果。
【Objective】Biochar loaded bacteria is a practical application of microbial immobilization. Biochar is considered the ideal carrier of microorganisms in recent years because of its large specific surface volume, pore diameter and good absorbability. Biochar loaded with Bacillus and other exogenous functional microorganisms can increase crop yield, improve root activity, and improve soil enzyme and microbial activity. However, In the process of gradual potassium deficiency, the impact of biochar-loaded potassium-solubilizing bacteria on soil enzyme activity and microbial community structure needs to be further explored. Therefore, this paper aims to explore the effect of potassium-solubilizing bacteria-loaded biochar on soil microbial characteristics.【Method】Based on pot experiment with ryegrass and five treatments: control (CK), chemical potassium fertilizer (KCl), inoculation of potassium solubilizing bacteria (KSB), application of biochar (BC) and potassium solubilizing bacteria loaded biochar (BC-KSB), the change characteristics of soil urease, acid phosphatase, invertase and catalase enzyme activities and microbial community structure were analyzed Also the effects of biochar-loaded potassium solubilizing bacteria composite materials on soil nutrients, soil pH, microbial carbon, microbial nitrogen and ryegrass yield were discussed.【Results】The soil urease and acid phosphatase activity increased first and then decreased while the soil invertase and catalase activity decreased with an increase in the number of harvests for treatments with microbial agents or biochar. . Compared with other fertilization treatments, BC-KSB was more conducive to the increase of soil urease, invertase, acid phosphatase and catalase activities. In terms of soil bacterial community, BC-KSB improved the species diversity and flora uniformity of soil bacteria, increased the abundance of soil beneficial bacteria (Chloroflexi, Actinobacteriota, Bacillus and Bradyrhizobium), and inhibited the reproduction of soil pathogenic bacteria (Proteobacteria and Rhodobacteria). Compared with CK, all fertilization treatments significantly increased the dry weight of ryegrass and BC-KSB treatment showed the largest increase. Also, compared with CK and KCl, BC-KSB treatment can significantly increase the contents of soil microbial carbon, microbial nitrogen, organic matter, total nitrogen and available potassium. However, the content of soil total potassium and total phosphorus in different treatments showed no significant difference. Furthermore, BC significantly increased soil pH compared to other treatments. Redundancy analysis showed that soil organic matter, available potassium, acid phosphatase, urease and microbial nitrogen were the main influencing factors of bacterial community structure, whereas the growth of ryegrass was mainly affected by Burkholderia and Rhodobacteria.【Conclusion】KSB loaded biochar has a positive impact on ryegrass yield, soil nutrients, soil enzyme activity, and bacterial community structure, which provides profound significance for fertilizing soil and improving soil ecological environment.
LI Changjun, LI Ting, LI Lulu, MIAO Li, WEI Wei, WANG Zhiao. Effects of Potassium-Solubilizing Bacteria Loaded Biochar on Soil Enzyme Activity and Microbial Community Structure[J]. Acta Pedologica Sinica,,[In Press]