State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences
Supported by the National Natural Science Foundation of China (Nos. 42020104004 and 52022028)
【Objective】Low phosphorus (P) availability limits the increase in the productive capacity of acidic soils. The bacteria phoC and phoD genes encode acid and alkaline phosphatase (ACP and ALP), respectively, which mineralize organic phosphorus (P) to inorganic P, are affected differently under different fertilization regimes. However, the combined responses of phosphorus-solubilizing microorganisms (PSM) to fertilization strategies and the rhizosphere effect are still unclear.【Method】In this study, we evaluated the response of maize to the interaction of different nitrogen forms (ammonium nitrogen and nitrate nitrogen) and phosphate fertilizer levels. The phoC and phoD genes, separately coding for acid and alkaline phosphatase productions, were used as molecular markers to investigate the effects of fertilization strategies and rhizosphere effect on soil phosphatase activities and associated functional microbial communities in acidic soil.【Result】The rhizosphere effect significantly increased soil phosphatase activities in the rhizosphere. ALP activities in the rhizosphere under nitrate-nitrogen treatment were lower than in the corresponding ammonium nitrogen treatment. Also, the strength of the rhizosphere effect was greater than that of nitrogen forms and phosphate fertilizer levels. Nitrogen forms, phosphate fertilizer levels and rhizosphere effect all significantly affected the operational taxonomic units (OTU) number and Shannon index of phoD-harboring bacteria, but only nitrogen forms and rhizosphere effect affected the OTU number of phoC-harboring bacteria. Principal coordinate analysis (PCoA) and PERMANOVA analysis showed that the rhizosphere effect exhibited more influence on the phoC- and phoD-harboring bacterial community composition than nitrogen forms and phosphate fertilizer levels, with more effects on the phoD-harboring bacterial community. The stimulation of soil phosphatase activities in the rhizosphere was closely related to the increase in soil organic matter. Additionally, changes in the composition and structure of phoC-harboring bacterial community were mainly related to the changes in rhizosphere nutrients, while the changes of phoD-harboring bacterial community structure may be attributed to combined effects of root exudates and nutrient changes.【Conclusion】The rhizosphere showed more influence on soil phosphatase activities and associated functional bacterial communities than nitrogen forms and phosphate fertilizer levels in acidic soil. However, the strength of the effect strongly relied on the fertilization strategies.
GUO Long, FENG Tongyu, XUE Zhuangzhuang, WANG Chao, SHEN Renfang. Effects of Nitrogen Form and Phosphorus Fertilizer on Phosphorus-solubilizing Bacteria and Phosphatase of Maize Rhizosphere in Acidic Red Soil[J]. Acta Pedologica Sinica, DOI:10.11766/trxb202108250454,[In Press]