Avaliação do biomaphos sobre os atributos químicos e biológicos do solo e o desempenho de forrageiras no cerrado

Abstract

Brazilian livestock farming occupies a leading position worldwide in the production and export of fresh beef, sustained predominantly by extensive tropical pasture systems. This performance is associated with continuous investments in agricultural technologies, including the development of adapted forage cultivars and bio-inputs. Among the promising strategies to increase the productivity of livestock systems in low fertility soils in the Cerrado region, the use of phosphorus-solubilizing microbial inoculants, such as BiomaPhos, stands out. This national bioinput is formulated with strains of Bacillus megaterium (BRM 119) and Bacillus subtilis (BRM 2084), microorganisms recognized for their ability to increase phosphorus availability in the soil and promote plant growth. This study aimed to evaluate the effects of different doses of BiomaPhos (0, 250, 500, 750, and 1,000 mL ha⁻¹), applied in conjunction with 50% of the recommended dose of phosphorus (P₂O₅), on the chemical and biological attributes of the soil, phosphorus fractions, and the morphological performance of the forage plants Urochloa brizantha cv. Marandu and Megathyrsus maximus cv. BRS Zuri, grown in dystrophic Red Latosol representative of the Cerrado. The experiment was conducted in open-air PVC pots between 2022 and 2023 at Embrapa Agropecuária Oeste in Dourados MS, using a randomized block design with subdivided plots and four replicates. The soil layers (40–60, 20–40, and 0–20 cm). During the experimental cycle, four cuts of the forage plants were made, with measurement of height, determination of dry matter mass, and leaf phosphorus content. Chemical and biological analyses of the soil were conducted, including pH, nutrients (Ca, Mg, K, P), total carbon, total nitrogen, and β-glycosidase enzyme activity. Additionally, phosphorus fractionation was performed according to Hedley et al. (1982) to evaluate the labile, moderately labile, and non-labile forms of the nutrient. The results showed that inoculation with BiomaPhos promoted significant improvements in the biological and chemical attributes of the soil, with different responses among the forage species. The cultivar Urochloa brizantha cv. Marandu showed greater accumulation of organic matter (32.60), carbon (1.89), and high β-glycosidase enzyme activity (41.30), favoring phosphorus absorption in the leaf blade (102.88) and biomass accumulation (335.21). In turn, Megathyrsus maximus cv. BRS Zuri stood out for its efficient mobilization of labile phosphorus fractions, indicating greater rhizospheric interaction with microorganisms. The 750 and 1.000 mL ha⁻¹ doses of BiomaPhos were the most efficient in improving the chemical and biological attributes of the soil, especially when associated with BRS Zuri. The results indicate that the adoption of phosphate inoculant, in conjunction with adapted forage species, represents a viable strategy for promoting improvements in soil quality, nutrient cycling, and reducing dependence on phosphate mineral fertilizers in Cerrado soils.