Zonas de manejo do teor de fósforo (P) e resposta da soja inoculada com solubilizador de fosfato

• Ano de defesa: 2022
• Autor(a) principal: Guesser, Vagner Portes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• dARK ID: ark:/26339/001300000dgcr
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Agronomia; UFSM; Programa de Pós-Graduação em Agricultura de Precisão; Colégio Politécnico da UFSM
• Palavras-chave em Português: Fósforo; Geoestatística; Bacillus sp.; Microorganismos; Agricultura de precisão; Phosphorus; Geostatistics; Microorganisms; Precision agriculture; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA
• Link de acesso: http://repositorio.ufsm.br/handle/1/26219

Phosphorus (P) acts on the energy metabolism of plants and in most Brazilian soils its availability is low, and phosphate solubilizing microorganisms (MSP) are promising in the availability of P to plants, through the availability of insoluble phosphates. Also, the spatial variability of P can be estimated through precision agriculture and generate management zones for its availability. The work was carried out in the municipality of Dom Pedrito-RS, in an experimental area of 5.7 ha-¹ . The determination of the spatial variability of the P content in the soil was measured in a regular sampling grid with 40 points, from the layer 0 to 20 cm. The detection of spatial variability, geostatistical modeling, preparation of the thematic map of P content and generation of P management zones were performed using the QGIS software version 3.16, using the Smart Map plugin. The cultivar used was BMX Zeus Ipro with 18 seeds m-¹ , spaced 50 cm-¹ . The phosphorus solubilizer contained strains B119 (Bacillus megaterium) and B2084 (Bacillus subtilis) with 4x109 viable cells per ml of product, applied via directed jet in the sowing furrow at a dose of 200 ml-¹ of commercial product ha-¹ and flow of 20 liters ha-¹ . The soluble mineral source was applied to the sowing line at a dose of 80 kg ha-¹ of diphosphate pentoxide (P2O5). The experimental design was randomized blocks in a factorial scheme 2 (management zones) x 3 (sources of availability) and 4 replications. The P content in the grain (%), in the leaves (g kg-¹ dry matter) and in the soil (mg dm-¹ ), the weight of a thousand grains (g-¹ ) and the productivity (kg ha-¹ ). The thousand-grain mass increased by 5.84% with the solubilizer and 4.79% with the mineral P source. The P content in the grain was 5.55% higher with the mineral source, compared to the control, not differing from the levels observed for the solubilizer. The supply of P via mineral source resulted in higher P content in the soil after the soybean harvest. Productivity was higher with the mineral source and solubilizer, compared to the control. Management zones with higher P availability showed productivity 9.44% above the ZM with lower availability. The P content in the grains was higher in ZM with lower P availability. Yield is responsive to the addition of P in areas of lower availability, with an increase of 8.51% via solubilizer and 11.57% via mineral source, compared to the nonaddition of the nutrient. The delimitation of ZM, based on the availability of P in the soil, indicated a reduction in the cost of supplying P, either via mineral source or solubilizer. The P solubilizer was able to supply the soybean demand and can replace the mineral source when the P contents in the soil are above the lower limit of the average interpretation class.