The overuse of N fertilizers has caused serious environmental problems (e.g., soil acidification, excessive N₂O in the air, and groundwater contamination) and poses a serious threat to human health. Improving N fertilizer utilization efficiency and plant uptake is an alternative for N fertilizers overuses. Enterobacter cloacae is an opportunistic pathogen, also used as plant growth-promoting rhizobacteria (PGPR), has been widely presented in the fields of bioremediation and bioprotection. Here we developed a new N fixation-release model by combining biochar with E. cloacae. The efficiency of the model was evaluated using a greenhouse pot experiment with maize (Zea mays L.) as the test crop. The results showed that biochar combined with E. cloacae significantly increased the N content. The application of biochar combined with E. cloacae increased total N in soil by 33% compared with that of N fertilizers application. The N-uptake and utilization efficiency (NUE) in plant was increased 17.03% and 14.18%, respectively. The activities of urease, dehydrogenase and fluorescein diacetate hydrolase (FDA) was improved, the catalase (CAT) activity decreased. Analysis of the microbial community diversity revealed the abundance of Proteobacteria, Actinobacteria, Firmicutes, and Gemmatimonadetes were significantly improved. The mechanism under the model is that E. cloacae acted as N-fixation by capturing N₂ from air. Biochar served as carrier, supporting better living environment for E. cloacae, also as adsorbent adsorbing N from fertilizer and from fixed N by E. cloacae, the adsorption in turn slower the N release. Altogether, the model promotes N utilization by plants, improves the soil environment, and reduces N pollution.

氮肥的过度使用造成了严重的环境问题（如土壤酸化、空气中过量的N ₂ O 和地下水污染），并对人类健康构成严重威胁。提高氮肥利用效率和植物吸收是氮肥过度使用的替代方案。阴沟肠杆菌是一种机会致病菌，也被用作植物促生根际细菌（PGPR），已广泛应用于生物修复和生物保护领域。在这里，我们通过将 biochar 与E结合开发了一种新的 N 固定释放模型。泄殖腔。使用以玉米 ( Zea mays L.) 作为试验作物的温室盆栽试验来评估模型的效率。结果表明，生物炭与大肠杆菌结合。cloacae显着增加了 N 含量。生物炭与E结合的应用。与施氮肥相比，泄殖腔使土壤中总氮含量增加33%。植物对氮的吸收和利用效率（NUE）分别提高了17.03%和14.18%。脲酶、脱氢酶和荧光素二乙酸水解酶（FDA）活性提高，过氧化氢酶（CAT）活性降低。微生物群落多样性分析显示，变形菌门、放线菌门、厚壁菌门和宝石单胞菌门的丰度显着提高。该模型下的机制是E。泄殖腔通过从空气中捕获 N _{2起到固氮作用。}生物炭作为载体，为大肠杆菌提供更好的生存环境。泄殖腔，也可作为吸附剂，从肥料中吸附氮素，并由E固定氮素。cloacae，吸附反过来减慢 N 释放。总而言之，该模型促进了植物对氮的利用，改善了土壤环境，减少了氮污染。