Potential of endophytic phosphorus-solubilizing bacteria to improve soil fertility, P uptake, and yield of maize (Zea mays L.) cultivated in alluvial soil in dikes in Vietnam

N.Q.Khuong,LeT.Quang,L.V.Thuc,T.N.Huu,L.T.M.Thu,T.T.B.Van,D.T.Xuan,N.H.Hue,N.T.T.Le,P.D.Tien,T.C.Nhan,L.N.T.Xuan,N.T.T.Xuan

Abstract: This study aimed to (i) select endophytic bacteria in maize root for its phosphorus solubilization ability and (ii) evaluate the efficacy of selected indigenous bacterial strains on soil fertility, phosphorus (P) uptake, growth, and maize yield. A total of 31 maize root samples were collected from An Phu District, An Giang Province, to isolate the bacteria. In addition, the pot experiment was conducted with nine treatments of (i) 100% P of the recommended fertilizer formula (RFF), (ii) 75% P of the RFF, (iii) 50% P of the RFF, (iv) 25% P of the RFF, (v) 75% P of the RFF plus a mixture of the 3 selected strains, (vi) 50% P of the RFF plus a mixture of the 3 selected strains, (vii) 25% P of the RFF plus a mixture of the 3 selected strains, (viii) 0% P of the RFF plus a mixture of the 3 selected strains, and (ix) 0% P of the RFF plus none of the 3 selected strains. The results identified 72 isolates from LGI medium. All isolates were screened in a broth medium at pH 5.0, but only 16 isolates obtained OD660 > 0.5. All 16 isolates were able to solubilize various insoluble P fractions. Of those, strain ASD-21 had the highest P solubilization ability for the insoluble Al-P compound. Strains ASD-08 and ASD-21 had the highest Fe-P concentration at 39.8–41.5 mg P L-1. Strains ASD-08 and ASD-21 had the highest Ca-P concentration (46.6–51.3 mg P L-1) for 48 h of incubation. They were identified as Enterobacter spp. Results also showed the application of a mixture of strains ASD-08, ASD-10, and ASD-21 increased soil fertility by increasing phosphorus content by 13.7 mg P kg-1 and replacing 25% of P fertilizer, but this mixture did not change maize yield.

Keywords: alluvial soil; dike; endophytic bacteria; maize yield; phosphorus solubilization

Date published: 2022-03-11