Desenvolvimento vegetativo e reprodutivo da soja em função da inoculação de bactérias solubilizadoras de fósforo e adubação fosfatada
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Data
2022-07-18
Autores
Pereira, Gabriel de Marchi Fernandes
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Universidade Estadual Paulista (Unesp)
Resumo
O fósforo é um nutriente essencial às plantas, mas encontra-se em baixa disponibilidade em solos tropicais. Por isso são necessárias grandes doses de adubos fosfatados, para que as culturas obtenham altas produtividades, sendo comum o uso de fertilizantes de baixa solubilidade, para reduzir o custo de implantação de lavouras. Sem ele, a produtividade da cultura da soja é baixa, há redução no porte da planta e na altura de inserção das primeiras vagens. Objetivou-se, com esse trabalho, avaliar o efeito vegetativo e reprodutivo da soja inoculada com bactérias solubilizadoras de fósforo sob diferentes doses de adubação fosfatada na cultura da soja. O experimento foi conduzido na área experimental na UNESP em Dracena/SP, com clima classificado predominantemente do tipo Aw, e solo classificado como Argissolo Vermelho Amarelo distrófico. O delineamento experimental foi em blocos casualizados em esquema fatorial 3x5 com parcelas subdivididas, com quatro repetições. Os tratamentos quanto à inoculação foram: não inoculado, inoculação do BiomaPhos via semente na dose comercial (120 mL ha-1), inoculação do BiomaPhos via sulco de semeadura na dose de (150mL ha-1). As subparcelas foram compostas pelas doses de fósforo (0, 50, 100, 150, 200 kg P2O5 ha-1) aplicadas via sulco de semeadura. Foi realizada a coinoculação nas sementes da soja (cultivar NS 6700 IPRO) com Bradyrhizobium japonicum como fonte de nitrogênio. A semeadura foi feita sobre a palha de Urochloa brizantha (cultivar BRS Paiaguás). Em R2 foram realizadas medições indiretas de clorofila (leitura SPAD). Em R8 foram avaliados altura de plantas, altura de inserção da primeira vagem, número de nós, número de ramos, número de vagens e número de grãos por planta, massa de mil grãos e produtividade de grãos em kg ha-1. A inoculação via semente na dose 50 kg/ha obteve um melhor resultado diferindo estatisticamente dos outros modos de inoculação na altura de inserção da primeira vagem de soja. As maneiras de inoculação e doses de fósforo não apresentaram diferença estatística para o Índice SPAD no pleno florescimento; matéria seca (MS) matéria fresca (MF), altura de plantas, número de ramos, vagens e grãos por planta, peso médio de mil grãos (PMG) e número de nós da soja. As doses de P2O5 influenciaram positivamente a produtividade da cultura da soja com o controle sem inoculação, sendo que a máxima eficiência agronômica foi verificada com o fornecimento de 98 kg ha -1 de pentóxido de fósforo. Porém, se recomenda ao produtor a utilização da inoculação via sulco de semeadura das bactérias solubilizadoras de fósforo sem a utilização de adubo mineral na dose de 0 kg/ha em solos com teor médio de fósforo (8 mg dm³), a adubação fosfatada pode ser dispensada.
Phosphorus is an essential nutrient for plants, but it is in low availability in tropical soils. Therefore, large doses of phosphate fertilizers are necessary, so that the cultures obtain high yield, it is common the use of low solubility fertilizers, to reduce the cost of crops implantation. Without it, the productivity of the soybean crop is low, there is a reduction in the plant size and in the height of the first pods insertion. This work aims to evaluate the vegetative and reproductive effect of soybean inoculated with phosphorus-solubilizing bacteria under different doses of phosphate fertilization in soybean. The experiment will be carried out at UNESP in Dracena/SP in the experimental area, with climate predominantly classified as Aw, and soil classified as dystrophic Red Yellow Argissolo. The experimental design will be in randomized blocks in a factorial scheme 3x5 with split plots, with four replications. The plots will be composed by the inoculant use in soybean via seed at commercial dose, via sowing furrow and without use. The subplots were composed of phosphorus doses (0, 50, 100, 150, 200 kg P2O5 ha1) applied via the sowing furrow. Co-inoculation will be carried out in soybean seeds (cultivate NS 6700 IPRO) with Bradyrhizobium japonicum as nitrogen source. The sowing will be done on Urochloa brizantha straw (BRS Paiaguás farm). In the harvest will be evaluated the number of days elapsed between sowing and emergence of most seedlings, flowering about 50% of the plants and maturation about 90% of the pods in the plot. In R2 will be carried out of the chlorophyll indirect measurements (SPAD reading), it is determining the P content in the aerial part dry matter of the plants and counting the number of flowers per plant. In R8 will be evaluated, plant height, the first pod insertion height, number of nodes, number of branches, number of pods and number of grains per plant, thousand grain weight and grain yield in kg ha-1. The inoculation via seed at 50 kg/ha dose obtained a better result, differing statistically from the other inoculation modes at the first soybean pod insertion height. The inoculation ways and phosphorus doses did not present statistical difference for the SPAD Index at full flowering; dry matter (DM) fresh matter (MF), plant height, number of branches, pods and grains per plant, average weight of one thousand grains (PMG) and number of soybean nodes. The P2O5 doses positively influenced the soybean yield with the control without inoculation, and the maximum agronomic efficiency was verified with the supply of 98 kg ha-1 of phosphorus pentoxide. However, it is recommended to the grower to use the inoculation via the phosphorus solubilizing bacteria sowing furrow without the mineral fertilizer use dose of 0 kg/ha in soils with average phosphorus content (8 mg dm³). Phosphate fertilization can be dispensed.
Phosphorus is an essential nutrient for plants, but it is in low availability in tropical soils. Therefore, large doses of phosphate fertilizers are necessary, so that the cultures obtain high yield, it is common the use of low solubility fertilizers, to reduce the cost of crops implantation. Without it, the productivity of the soybean crop is low, there is a reduction in the plant size and in the height of the first pods insertion. This work aims to evaluate the vegetative and reproductive effect of soybean inoculated with phosphorus-solubilizing bacteria under different doses of phosphate fertilization in soybean. The experiment will be carried out at UNESP in Dracena/SP in the experimental area, with climate predominantly classified as Aw, and soil classified as dystrophic Red Yellow Argissolo. The experimental design will be in randomized blocks in a factorial scheme 3x5 with split plots, with four replications. The plots will be composed by the inoculant use in soybean via seed at commercial dose, via sowing furrow and without use. The subplots were composed of phosphorus doses (0, 50, 100, 150, 200 kg P2O5 ha1) applied via the sowing furrow. Co-inoculation will be carried out in soybean seeds (cultivate NS 6700 IPRO) with Bradyrhizobium japonicum as nitrogen source. The sowing will be done on Urochloa brizantha straw (BRS Paiaguás farm). In the harvest will be evaluated the number of days elapsed between sowing and emergence of most seedlings, flowering about 50% of the plants and maturation about 90% of the pods in the plot. In R2 will be carried out of the chlorophyll indirect measurements (SPAD reading), it is determining the P content in the aerial part dry matter of the plants and counting the number of flowers per plant. In R8 will be evaluated, plant height, the first pod insertion height, number of nodes, number of branches, number of pods and number of grains per plant, thousand grain weight and grain yield in kg ha-1. The inoculation via seed at 50 kg/ha dose obtained a better result, differing statistically from the other inoculation modes at the first soybean pod insertion height. The inoculation ways and phosphorus doses did not present statistical difference for the SPAD Index at full flowering; dry matter (DM) fresh matter (MF), plant height, number of branches, pods and grains per plant, average weight of one thousand grains (PMG) and number of soybean nodes. The P2O5 doses positively influenced the soybean yield with the control without inoculation, and the maximum agronomic efficiency was verified with the supply of 98 kg ha-1 of phosphorus pentoxide. However, it is recommended to the grower to use the inoculation via the phosphorus solubilizing bacteria sowing furrow without the mineral fertilizer use dose of 0 kg/ha in soils with average phosphorus content (8 mg dm³). Phosphate fertilization can be dispensed.
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Glycine max (L) Merrill, Crescimento, Palhada, Produção, Growth, Straw, Production