Residual da adubação fosfatada e efeito da inoculação com Azospirillum brasilense nas culturas em sistema plantio direto no Cerrado
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2019-02-20
Autores
Dickmann, Lourdes
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Universidade Estadual Paulista (Unesp)
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A busca por modelos sustentáveis para a agropecuária aliado a novas tecnologias, como o uso de bactérias diazotróficas, que promovem o crescimento de plantas, aumentam a eficiência do uso dos fertilizantes e trazem equilíbrio ambiental, torna-se indispensável principalmente nas regiões tropicais. Para isso, buscou-se avaliar em um LATOSSOLO VERMELHO Distrófico típico argiloso, em condições irrigadas e sob sistema plantio direto (SPD) no Cerrado, nos anos agrícolas de 2013/14 e 2015/16, 1) o efeito da adubação fosfatada e da inoculação ou não com A. brasilense sobre a nutrição e produtividade de matéria seca da parte aérea e raízes da aveia preta; 2) avaliar o efeito residual da adubação fosfatada e da decomposição da palhada da aveia preta sobre o crescimento e produtividade do milho inoculado ou não pelo A. brasilense e do capim Marandu em consórcio; e 3) após a colheita do milho, avaliar a produtividade e a qualidade bromatológica do capim Marandu, e o efeito de sua palhada sobre os componentes da produção e produtividade do feijoeiro de inverno em sucessão. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições, em esquema fatorial 5 x 2, ou seja, cinco doses de P2O5 na forma de MAP (0; 30; 60; 120 e 240 kg ha-1) aplicadas a lanço na semeadura da aveia preta cultivar IAPAR 61 em 2013, com ou sem a inoculação das sementes com a bactéria A. brasilense, na dose de 100 mL 25 kg-1 de sementes. Cada unidade experimental (parcela) constituiu-se de 4,4 m de largura por 10 m de comprimento, perfazendo 44 m2. Verificou-se no cultivo de 2013 que a inoculação de A. brasilense incrementou a produção de matéria seca da parte aérea e de raízes da aveia preta, assim como aumentou o comprimento de raízes e sua massa seca em 2015. Independente dos anos de cultivo, a adubação fosfatada residual não interferiu sobre o crescimento, componentes da produção e produtividade de grãos de milho consorciado com capim Marandu. Enquanto que, a inoculação das sementes de milho com A. brasilense proporcionou maiores teores foliares de nutrientes nos cultivos de 2013/14 e de 2015/16, além de promover ganhos na produção de matéria seca do primeiro e segundo corte (2015/16), com valores superiores em todos os componentes bromatológicos do capim Marandu. Com o efeito da palhada do consórcio milho/capim Marandu e principalmente da inoculação com A. brasilense antecessores ao cultivo de feijoeiro de inverno houve incrementos no estado nutricional das plantas, principalmente no segundo ano de cultivo (2016), entretanto, não trouxe respostas significativas sobre a produtividade de grãos. A adubação fosfatada residual, proporcionou efeito positivo para as plantas de feijoeiro de inverno cultivadas em 2014, com incremento dos componentes da produção e produtividade de grãos.
The search for sustainable models for agriculture associated with new technologies, such as the use of diazotrophic bacteria that promote plant growth, increase the efficiency of fertilizer use and bring environmental balance, making it indispensable mainly in tropical areas. This study was conducted on the red LATOSOL Distrofic, typical clayey, under irrigated conditions and under no-tillage system (NTS) in the Cerrado, in the agricultural years of 2013/14 and 2015/16. The aim of this study was to evaluate 1) the effect of phosphate fertilization and of the inoculation or not with A. brasilense on the nutrition and productivity of black oat shoot and roots dry matter; 2) to evaluate the residual effect of phosphate fertilization and black oat straw decomposition on the growth and yield of maize inoculated or not with A. brasilense and Marandu grass intercroped; and 3) after harvesting maize, to evaluate the productivity and the bromatological quality of the Marandu grass, and the effect of its straw on the components of the production and productivity of the winter bean in succession. The experimental design was randomized block, with four replications, in a factorial scheme 5 x 2, five P2O5 doses in the form of MAP (0; 30; 60; 120 and 240 kg ha-1) applied throwing during the sowing of black oat cultivar IAPAR 61 in 2013, with or without inoculation of the seeds with the bacterium A. brasilense, at the dose of 100 mL 25 kg-1 of seeds. Each experimental unit (plot) consisted of 4.4 m wide by 10 m length, totalling 44 m2. It was verified in the cultivation of 2013 that the inoculation of A. brasilense increased the production of black oat shoot and roots dry matter, as well as it increased the roots length and its dry matter in 2015. Independently of the years of cultivation, the residual phosphate fertilization did not interfere the growth, the production components and the maize grains yield intercropped with Marandu grass. While the inoculation of maize seeds with A. brasilense provided larger leaf contents in the cutivation of 2013/14 and of 2015/16, besides of promoting gains in dry matter production of the first and second cutting (2015/16), with greater values in all of bromatological components of Marandu grass. With the effect of the straw of maize/Marandu grass consortium and mainly of the inoculation with A. brasilense predecessors to the winter bean crop, there were increases in the nutritional status of the plants, mainly in the second year of cultivation (2016), however, it did not bring significant responses on grain yield. The residual phosphate fertilization provided a positive effect for the winter bean plants cultivated in 2014, with an increase in production components and grain yield.
The search for sustainable models for agriculture associated with new technologies, such as the use of diazotrophic bacteria that promote plant growth, increase the efficiency of fertilizer use and bring environmental balance, making it indispensable mainly in tropical areas. This study was conducted on the red LATOSOL Distrofic, typical clayey, under irrigated conditions and under no-tillage system (NTS) in the Cerrado, in the agricultural years of 2013/14 and 2015/16. The aim of this study was to evaluate 1) the effect of phosphate fertilization and of the inoculation or not with A. brasilense on the nutrition and productivity of black oat shoot and roots dry matter; 2) to evaluate the residual effect of phosphate fertilization and black oat straw decomposition on the growth and yield of maize inoculated or not with A. brasilense and Marandu grass intercroped; and 3) after harvesting maize, to evaluate the productivity and the bromatological quality of the Marandu grass, and the effect of its straw on the components of the production and productivity of the winter bean in succession. The experimental design was randomized block, with four replications, in a factorial scheme 5 x 2, five P2O5 doses in the form of MAP (0; 30; 60; 120 and 240 kg ha-1) applied throwing during the sowing of black oat cultivar IAPAR 61 in 2013, with or without inoculation of the seeds with the bacterium A. brasilense, at the dose of 100 mL 25 kg-1 of seeds. Each experimental unit (plot) consisted of 4.4 m wide by 10 m length, totalling 44 m2. It was verified in the cultivation of 2013 that the inoculation of A. brasilense increased the production of black oat shoot and roots dry matter, as well as it increased the roots length and its dry matter in 2015. Independently of the years of cultivation, the residual phosphate fertilization did not interfere the growth, the production components and the maize grains yield intercropped with Marandu grass. While the inoculation of maize seeds with A. brasilense provided larger leaf contents in the cutivation of 2013/14 and of 2015/16, besides of promoting gains in dry matter production of the first and second cutting (2015/16), with greater values in all of bromatological components of Marandu grass. With the effect of the straw of maize/Marandu grass consortium and mainly of the inoculation with A. brasilense predecessors to the winter bean crop, there were increases in the nutritional status of the plants, mainly in the second year of cultivation (2016), however, it did not bring significant responses on grain yield. The residual phosphate fertilization provided a positive effect for the winter bean plants cultivated in 2014, with an increase in production components and grain yield.
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Sustentabilidade, Bactérias diazotróficas, Avena strigosa, Zea mays L., Urochloa brizantha, Phaseolus vulgaris L., Sistema plantio direto, Sustainability, Diazotrophic bacteria, No-tillage system