Effects of Phosphorus Application Rate on Phosphohydrolase Activity and Distribution of Phosphate Solubilizing Bacteria in Paddy Soil

Li Yinghui; Xing Xiaoyi; Qiu Xu; Xu Shirong; Ni Fei; Zhao Lian; Yang Xianjun

doi:10.14083/j.issn.1001-4942.2024.02.015

Abstract：This paper aimed to explore the influences of phosphorus(P)fertilizer on soil P activation to-gether with the microbial driving mechanisms underlying,and to provide theoretical basis for P fertilizer man-agement and efficient use.Red paddy soil was used as material,and P fertilizer(KH2 PO4)were applied at rates of 20 mg/kg(P20),50 mg/kg(P50)and 80 mg/kg(P80).The soil was incubated at 25℃ for a week by indoor culture,and then the soil available P(AP)content,phosphatase activity and distribution of phosphate solubilizing bacteria(PSB)were determined.The results showed that the P effectiveness index(the ratio of AP increment to total P application rate)increased with the P application rate increasing.AP in-creased by 4.53,12.65 and 25.69 mg/kg under P application rates of 20,50,and 80 mg/kg,with P effec-tiveness indexes was 22.66％,25.30％and 32.11％,respectively.Activity of soil acid phosphatase(ACP)was higher than that of neutral and alkaline phosphatase,which was more responsive to P application;the ac-tivity at treatment P50 was the highest,followed by P20 and P80 treatments.Alpha diversity of phoD-contai-ning PSB in soil was significantly decreased by P application,and the community composition was affected.The relative abundance of OTU769(unknown taxa)was about 30％in treatment P50,which might promote the increases of phosphatases activity and available P content.The total relative abundance of OTU1036 and OTU975(Pseudomonas)in treatment P80 was up to 50％,which might increase organic acid content through dissolution of inorganic P by organic acid secretion.To sum up,the higher phosphate application in fertilizer improved supply efficiency of AP,and the increase of phosphatase activity might be one of the important rea-sons for AP increase under medium P application,whereas inorganic P dissolved by Pseudomonas should play more important roles in improving AP content under high P application.