Document Type : Original Article
Authors
1
Researcher, Department of Agronomy Research, Khuzestan Sugarcane Research and Training Institute, Ahvaz, Iran.
2
Director of Applied Research, Hakim Farabi Agro-Industry CO., Khuzestan, Iran
3
Head of Soil Science, Debal Khozaei Agro-Industry CO., Ahvaz, Iran.
4
Head of Water, Soil and Plant Laboratory Debal Khozaei Agro-Industry CO., Ahvaz, Iran.
5
Professor, Department of Soil Science , Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
10.30466/asr.2025.55605.1860
Abstract
Phosphate solubilizing bacteria are effective in improving the availability of phosphorus in calcareous soils by different mechanisms. The objective of this study was to investigate the effect of phosphate solubilizing bacteria inoculation on the microbial activity, availability and inorganic fractions of phosphorus in a calcareous soil cultivated with second ratoon sugarcane. For this purpose, this study was carried out in a research field (CP73-21 variety) in the Dabal Khozaei Agro-industry of, Khuzestan. The experiment was carried out in the form of a randomized complete block design with three treatments: 1- control (C), 2- inoculation of Enterobacter cloacae R33 (B33) and inoculation of bacterial consortium (Enterobacter cloacae R33, Brevundimonas sp. Staphylococcus hominis 9E) (Bmix). Phosphate solubilizing bacteria were applied using soil spraying method. Three months after the treatments inoculated, basal microbial respiration, microbial biomass carbon, soil available phosphorus and chemical fractions of phosphorus in the soil were measured. The results indicated the phosphate solubilizing bacteria inoculation caused a significant increase in microbial respiration, microbial biomass carbon, and soil available phosphorus. In the B33 and Bmix treatments, the available soil phosphorus concentration was 52.5% and 24.6 % higher than the control treatment, respectively. The B33 inoculation led to significant increase in the Ca2-P and Ca8-P fractions and decrease in Al-P and Ca10-P in the soil. The proportion of phosphorus inorganic fractions in control treatment was as follows: Ca10-P > Ca8-P > Fe -P > Al-P > Ca2-P, while in the B33 treatment, this trend was as follows: Ca8-P > Ca10-P > Fe-P > Ca2-P > Al-P. The results revealed that the B33 treatment was more effective in enhancement of the phosphorus availability in the soil than Bmix treatment. In general, the results of this study demonstrated that the inoculation of Enterobacter cloacae R33 can be effective in increasing the phosphorus availability in calcareous soil by conversion of phosphorus from less available fractions to fractions with more availability.
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