Efeito da inoculação com solubilizador de fósforo na morfofisiologia, fenologia e biomassa microbiana em plantas de algodão herbáceo

Abstract

Cotton is one of the main agricultural commodities that has gained prominence in recent years, with increasing demand in both domestic and international markets not only for its fiber but also for its various derived products. Additionally, one of the most expensive inputs in the production system is mineral fertilization, with phosphorus being one of the macronutrients that has driven research on the subject, as it is essential for plant metabolism and crucial for the growth and physiological processes of cotton, such as photosynthesis. Thus, studies utilizing phosphorus-solubilizing microorganisms have gained attention in recent years as an organic approach to ensuring phosphorus availability for crops. This study aimed to evaluate the physiological responses of herbaceous cotton subjected to different dosages of the BiomaPhos® inoculant, composed of the strains BRM 119 (Priestia megaterium) and BRM 2084 (Bacillus subtilis), as well as its influence on soil microbial biomass carbon. The experimental design adopted was completely randomized, with four treatments varying in BiomaPhos® dosage (control 0 mL, 0.3 mL, 0.6 mL, and 0.9 mL), each with eight replications. Biometric parameters (plant height, leaf number, stem diameter, and dry biomass), physiological parameters (gas exchange and chlorophyll a fluorescence), and microbial biomass carbon were evaluated. Biometric data were collected at two time points, 35 DAS and 98 DAS, while physiological data were collected at three time points, 35 DAS, 51 DAS, and 90 DAS. Microbial biomass carbon was analyzed at 98 DAS. The presence of microorganisms directly affected crop growth in terms of biometric parameters. Inoculated plants exhibited an earlier phenological development stage during the initial growth phases. Regarding physiological data, variables such as photosynthesis and instantaneous carboxylation efficiency showed positive responses to inoculation, with the 0.6 mL and 0.9 mL doses standing out. The 0.6 mL dose yielded the best results throughout the experiment, while the 0.9 mL dose exhibited the worst results starting from the reproductive phase. It can be concluded that the microorganisms influenced crop development, with the 0.6 mL dose being the most effective and therefore recommended.