Cereibacter sphaeroides ST16 and ST26 were used to solubilize insoluble P forms to improve P uptake, growth, and yield of rice in acidic and extreme saline soil

Abstract

Soluble phosphorus (P) and P uptake are heavily affected by adverse conditions, such as salinity and acidity. The study aimed to evaluate the effects of P-solubilizing purple nonsulfur bacteria (PSPNSB) Cereibacter sphaeroides on soil characteristics, P uptake, growth, and yield of rice planted in saline soil in Thoi Binh - Ca Mau under greenhouse conditions. The pot experiment was completely randomized in blocks with two factors. Factor A was the rate of phosphorus chemical fertilization at 0, 25, 50, 75, and 100% P according to the recommendation. Factor B was the PSPNSB including a single strain of C. sphaeroides ST16 or C. sphaeroides ST26 and a mixture of them. The soluble P in soil increased by 16.4-18.2% when C. sphaeroides ST16 and ST26 were supplied singly or in the mixture, leading to the increase in total P uptake in rice by 19.2-30.1% in two continuous crops. Moreover, the growth and yield components of rice were also improved, leading to an increase in rice grain yield by 7.20-17.7%. Moreover, supplying the C. sphaeroides strains reduced Na+ in soil and Na content in stem, leaves, and grains, leading to the reduction in proline content in rice. Supplying the C. sphaeroides ST16 and ST26 or their mixture replaced 100% P fertilizer but still ensured the rice grain yield. Further approaches should be made to investigate the possibility of the potent strains replacing chemical P fertilizers under field conditions.