RESUMO

Abstract Nitrogen (N) and potassium (K) in potato crop planting synergistically increase tuber yield, but there are no studies on this interaction in sidedressing. In two experiments with 'Atlantic' potato combinations of four N rates (0, 50, 100, and 150 kg ha-1) with four K2O rates (0, 100, 200, and 300 kg ha-1) were applied in sidedressing in a 4×4 factorial scheme with three replications in a completely randomized design. Adjacent commercial fields were sampled to economic comparisons with experimental results. Significant interaction between N and K sidedressing rates with tuber yields increase also was confirmed and classified as Liebig-synergism. Compared to the isolated N and K applications in sidedressing, joint N and K fertilizations, respectively, increases by 11% and 48% marketable tuber yields in the summer-fall experiment, and 12% and 7% in the spring experiment. Joint N and K applications as sidedressing was more profitable than planting fertilization, mainly at higher N and K rates. The response of specific gravity of 'Atlantic' potato tubers to the N and K sidedressing rates was mediated by interactions between edaphoclimatic conditions and inputs of N and K. The combined application of N and K sidedressing rates increased specific gravity in the summer-fall experiment, but had a negative effect in the spring experiment. Therefore, our results provide strong evidence that the fertilization management for potato crop in Brazil can be modified by applying higher amounts of N and K in sidedressing to match nutritional needs of the crop.

Assuntos

RESUMO

The acid release of phosphates from rock phosphates (RP) and the retention of ammonium by inorganic phosphates have been studied separately in composting; however, there is a gap in the knowledge of combined application of RP with organic residues and microorganisms. The objectives were to evaluate the combined application of fresh poultry litter (PL) with RP and P-solubilizing microorganisms (M) on soil organic matter pools, microbial biomass C (MB-C) and on whole-plant silage maize and grain yields. Two field experiments tested the effects of timing of applications of PL (8 Mg ha–1), RP (4 Mg ha–1) and microorganisms on soil organic matter pools, nutritional aspects and productive components of maize crop whole-plant silage. A second experiment evaluated the effects of RP doses (0, 3, 6 and 9 Mg ha–1) with a fixed dose of PL (8 Mg ha–1) on maize grains. Application of PL+RP decreased soil organic C, while RP alone increased the humin fraction C compared to the control. The MB-C in soil with PL and PL+RP+M increased in comparison to the control and the RP. The application of PL, based on an average of fall and spring, increased leaves + stem dry matter, while in the fall on its own, the highest cob yield was observed in the combination of PL+RP, showing synergistic effects. The best ratio of poultry litter to rock phosphate combination is 2:1 in the anticipated fall application on the maize silage crop or immediate application on the maize grain crops.

Assuntos

RESUMO

The acid release of phosphates from rock phosphates (RP) and the retention of ammonium by inorganic phosphates have been studied separately in composting; however, there is a gap in the knowledge of combined application of RP with organic residues and microorganisms. The objectives were to evaluate the combined application of fresh poultry litter (PL) with RP and P-solubilizing microorganisms (M) on soil organic matter pools, microbial biomass C (MB-C) and on whole-plant silage maize and grain yields. Two field experiments tested the effects of timing of applications of PL (8 Mg ha–1), RP (4 Mg ha–1) and microorganisms on soil organic matter pools, nutritional aspects and productive components of maize crop whole-plant silage. A second experiment evaluated the effects of RP doses (0, 3, 6 and 9 Mg ha–1) with a fixed dose of PL (8 Mg ha–1) on maize grains. Application of PL+RP decreased soil organic C, while RP alone increased the humin fraction C compared to the control. The MB-C in soil with PL and PL+RP+M increased in comparison to the control and the RP. The application of PL, based on an average of fall and spring, increased leaves + stem dry matter, while in the fall on its own, the highest cob yield was observed in the combination of PL+RP, showing synergistic effects. The best ratio of poultry litter to rock phosphate combination is 2:1 in the anticipated fall application on the maize silage crop or immediate application on the maize grain crops.(AU)

Assuntos

RESUMO

Estoques de carbono em macroagregados do solo possuem relação com a taxa de sequestro de C no solo em sistema plantio direto. Objetivou-se avaliar os estoques de carbono em macroagregados (12,5-19,0mm) em função do revolvimento ocasional e/ou da calagem de um Latossolo Vermelho Distroférrico típico textura muito argilosa, sob sistema plantio direto há 17 anos em Pato Branco, sudoeste do Paraná. A partir de outubro de 2009, foi avaliado um experimento em parcelas sub-subdivididas, tendo como parcelas, épocas de amostragens após 6, 12 e 20 meses do revolvimento do solo e/ou calagem; nas subparcelas, manejos de solo, sem e com revolvimento do solo com uma aração e uma gradagem; e, nas sub-subparcelas, níveis de calagem, sem e com calcário para elevar o índice de saturação por bases para 70%. Dos 6 aos 12 meses, a aplicação de calcário em superfície ou incorporado aumentou os estoques de C dos macroagregados na camada de 0,10-0,20m. Após 20 meses, a incorporação de calcário em solo reduziu os estoques de C dos macroagregados somente na camada de 0-0,10m. Assim, a calagem na superfície é fundamental para a manutenção e aumento dos estoques de C em macroagregados de solo sob sistema plantio direto, mantendo-o consolidado.(AU)

Carbon stocks in soil macroaggregates are related to the rate of soil C sequestration in no-tillage system. This study aimed to evaluate carbon stocks in macroaggregates (12.5 to 19.0mm) as a function of the occasional tillage and/or liming of a Hapludox loamy clayey under no-tillage for 17 years in Pato Branco, Paraná southwest, Brazil. Starting from October 2009, it was evaluated an experiment with split-split plots, with plots as sampling dates after 6, 12 and 20 months of the occasional tillage and/or liming; the subplots as soil management, with and without occasional soil tillage with plowing and disking; and as sub-subplots, liming levels, with and without limestone to raise the base saturation index to 70%. From 6 to 12 months, the limestone application on surface or incorporated increased C stocks of macroaggregates in the 0.10-0.20m layer. After 20 months, the incorporation of limestone in soil reduced C stocks in macroaggregates only in the 0-0.10m layer. Thus, the surface liming is essential for the maintenance and enhancement of C stocks in macroaggregates of no-tillage system, keeping it consolidated.(AU)

Assuntos

RESUMO

Estoques de carbono em macroagregados do solo possuem relação com a taxa de sequestro de C no solo em sistema plantio direto. Objetivou-se avaliar os estoques de carbono em macroagregados (12,5-19,0mm) em função do revolvimento ocasional e/ou da calagem de um Latossolo Vermelho Distroférrico típico textura muito argilosa, sob sistema plantio direto há 17 anos em Pato Branco, sudoeste do Paraná. A partir de outubro de 2009, foi avaliado um experimento em parcelas sub-subdivididas, tendo como parcelas, épocas de amostragens após 6, 12 e 20 meses do revolvimento do solo e/ou calagem; nas subparcelas, manejos de solo, sem e com revolvimento do solo com uma aração e uma gradagem; e, nas sub-subparcelas, níveis de calagem, sem e com calcário para elevar o índice de saturação por bases para 70%. Dos 6 aos 12 meses, a aplicação de calcário em superfície ou incorporado aumentou os estoques de C dos macroagregados na camada de 0,10-0,20m. Após 20 meses, a incorporação de calcário em solo reduziu os estoques de C dos macroagregados somente na camada de 0-0,10m. Assim, a calagem na superfície é fundamental para a manutenção e aumento dos estoques de C em macroagregados de solo sob sistema plantio direto, mantendo-o consolidado.

Carbon stocks in soil macroaggregates are related to the rate of soil C sequestration in no-tillage system. This study aimed to evaluate carbon stocks in macroaggregates (12.5 to 19.0mm) as a function of the occasional tillage and/or liming of a Hapludox loamy clayey under no-tillage for 17 years in Pato Branco, Paraná southwest, Brazil. Starting from October 2009, it was evaluated an experiment with split-split plots, with plots as sampling dates after 6, 12 and 20 months of the occasional tillage and/or liming; the subplots as soil management, with and without occasional soil tillage with plowing and disking; and as sub-subplots, liming levels, with and without limestone to raise the base saturation index to 70%. From 6 to 12 months, the limestone application on surface or incorporated increased C stocks of macroaggregates in the 0.10-0.20m layer. After 20 months, the incorporation of limestone in soil reduced C stocks in macroaggregates only in the 0-0.10m layer. Thus, the surface liming is essential for the maintenance and enhancement of C stocks in macroaggregates of no-tillage system, keeping it consolidated.

Assuntos

RESUMO

The interdependence between the C and N cycles is reflected by the levels of soil organic matter (SOM). SOM and organic C levels in water soluble (C-WS) humic acids (C-HA), fulvic acids (C-FA), and humin fractions (C-H) were evaluated through the classic chemical fractionation method in samples of a Rhodic Eutrudox from a randomized blocks experimental design, with split-split-plots using five nitrogen sidedressing levels for corn (0; 60; 120; 180; and 240 kg ha-1 N) as the main treatment, two crop sequences (corn-corn and soybean-corn) as the secondary treatment, and two sampling depths (0 to 0.2 and 0.2 to 0.4 m) as a sub-subtreatment. Nitrogen fertilization did not affect SOM levels, but favored the synthesis of substances in the C-HA fraction. There was a quadratic effect of N rates on the C-WS and C-FA levels in the corn-corn succession. The soybean-corn succession resulted in larger SOM and organic C levels in the C-H fraction.

A interdependência dos ciclos de C e N reflete-se nos teores de matéria orgânica do solo (MOS). Em um delineamento experimental em blocos casualizados, com parcelas sub-subdivididas, tendo como tratamento principal cinco doses de nitrogênio de cobertura na cultura do milho (0; 60; 120; 180 e 240 kg ha-1 de N), como tratamento secundário, as sucessões milho-milho e soja-milho, e como sub-subtratamento, duas profundidades de amostragem (0 a 0.2 e 0.2 a 0.4 cm), avaliaram-se os teores de MOS e de C orgânico nas frações solúvel em água (C-SA), ácidos húmicos (C-AH), ácidos fúlvicos (C-AF) e humina (C-H), por meio do método clássico de fracionamento químico, em um Latossolo Vermelho eutrófico, de textura argilosa. A adubação nitrogenada não afetou os teores de MOS, mas favoreceu a síntese de compostos da fração C-AH. Houve efeito quadrático das doses de N nos teores de C-SA e de C-AF na sucessão milho-milho. A sucessão soja-milho resultou em maiores teores de MOS e de C orgânico na fração humina.

RESUMO

The interdependence between the C and N cycles is reflected by the levels of soil organic matter (SOM). SOM and organic C levels in water soluble (C-WS) humic acids (C-HA), fulvic acids (C-FA), and humin fractions (C-H) were evaluated through the classic chemical fractionation method in samples of a Rhodic Eutrudox from a randomized blocks experimental design, with split-split-plots using five nitrogen sidedressing levels for corn (0; 60; 120; 180; and 240 kg ha-1 N) as the main treatment, two crop sequences (corn-corn and soybean-corn) as the secondary treatment, and two sampling depths (0 to 0.2 and 0.2 to 0.4 m) as a sub-subtreatment. Nitrogen fertilization did not affect SOM levels, but favored the synthesis of substances in the C-HA fraction. There was a quadratic effect of N rates on the C-WS and C-FA levels in the corn-corn succession. The soybean-corn succession resulted in larger SOM and organic C levels in the C-H fraction.

A interdependência dos ciclos de C e N reflete-se nos teores de matéria orgânica do solo (MOS). Em um delineamento experimental em blocos casualizados, com parcelas sub-subdivididas, tendo como tratamento principal cinco doses de nitrogênio de cobertura na cultura do milho (0; 60; 120; 180 e 240 kg ha-1 de N), como tratamento secundário, as sucessões milho-milho e soja-milho, e como sub-subtratamento, duas profundidades de amostragem (0 a 0.2 e 0.2 a 0.4 cm), avaliaram-se os teores de MOS e de C orgânico nas frações solúvel em água (C-SA), ácidos húmicos (C-AH), ácidos fúlvicos (C-AF) e humina (C-H), por meio do método clássico de fracionamento químico, em um Latossolo Vermelho eutrófico, de textura argilosa. A adubação nitrogenada não afetou os teores de MOS, mas favoreceu a síntese de compostos da fração C-AH. Houve efeito quadrático das doses de N nos teores de C-SA e de C-AF na sucessão milho-milho. A sucessão soja-milho resultou em maiores teores de MOS e de C orgânico na fração humina.

RESUMO

This work evaluates effects of cattle manure vermicompost in association with liming on soil fertility indexes. The experiment was carried out in greenhouse conditions, in pots containing samples of a Typic Hapludox, medium-textured soil. Five levels of vermicompost (equivalent to 0, 28, 42, 56, and 70 t ha-1, dry weight) and five liming levels (to raise base saturation to 20, 30, 40, 50, and 60%) were combined in a factorial scheme and samples were incubated for 180 days. Samples of the same soil received the equivalent to 70 t ha-1 of the cattle manure used to produce the vermicompost, and the same lime rates. Cattle manure was better than vermicompost to supply K and Mg. Small differences in P supply were observed between the manures. The vermicompost increased the levels of Ca, pH, organic matter (OM) and CEC more than the manure. C-humic acids decreased and C-humin increased with vermicompost application. With liming, C-humic acids decreased, but the total content of OM was not affected.

Os efeitos do vermicomposto de esterco de curral associado à calagem em atributos da fertilidade do solo foram avaliados através de experimento em vasos empregando um Latossolo Vermelho, distrófico, textura média. Cinco doses do vermicomposto (equivalentes a 0; 28; 42; 56 e 70 t ha-1, peso seco) e cinco doses de calcário (visando elevar a saturação por bases a: 20; 30; 40; 50 e 60%) foram combinadas em esquema fatorial, sendo as amostras de solo incubadas por 180 dias. Para comparação entre o vermicomposto e o esterco de curral, amostras do mesmo solo receberam o equivalente a 70 t ha-1 do esterco de curral que originou o vermicomposto e as cinco doses de calcário listadas anteriormente. Através do cálculo do Índice de Eficiência Agronômica, foi verificado que o potencial de fornecimento de K e de Mg pelo esterco é maior do que o do vermicomposto, e que o de P, é semelhante. O vermicomposto aumentou os teores de Ca2+ e de matéria orgânica (MO), os valores de pH em CaCl2 e a CTC a pH 7. Com o aumento das doses de vermicomposto houve diminuição do C-ácidos húmicos e aumento do C-humina e com a calagem o C-total não aumentou mas houve diminuição do C-ácidos húmicos.

RESUMO

This work evaluates effects of cattle manure vermicompost in association with liming on soil fertility indexes. The experiment was carried out in greenhouse conditions, in pots containing samples of a Typic Hapludox, medium-textured soil. Five levels of vermicompost (equivalent to 0, 28, 42, 56, and 70 t ha-1, dry weight) and five liming levels (to raise base saturation to 20, 30, 40, 50, and 60%) were combined in a factorial scheme and samples were incubated for 180 days. Samples of the same soil received the equivalent to 70 t ha-1 of the cattle manure used to produce the vermicompost, and the same lime rates. Cattle manure was better than vermicompost to supply K and Mg. Small differences in P supply were observed between the manures. The vermicompost increased the levels of Ca, pH, organic matter (OM) and CEC more than the manure. C-humic acids decreased and C-humin increased with vermicompost application. With liming, C-humic acids decreased, but the total content of OM was not affected.

Os efeitos do vermicomposto de esterco de curral associado à calagem em atributos da fertilidade do solo foram avaliados através de experimento em vasos empregando um Latossolo Vermelho, distrófico, textura média. Cinco doses do vermicomposto (equivalentes a 0; 28; 42; 56 e 70 t ha-1, peso seco) e cinco doses de calcário (visando elevar a saturação por bases a: 20; 30; 40; 50 e 60%) foram combinadas em esquema fatorial, sendo as amostras de solo incubadas por 180 dias. Para comparação entre o vermicomposto e o esterco de curral, amostras do mesmo solo receberam o equivalente a 70 t ha-1 do esterco de curral que originou o vermicomposto e as cinco doses de calcário listadas anteriormente. Através do cálculo do Índice de Eficiência Agronômica, foi verificado que o potencial de fornecimento de K e de Mg pelo esterco é maior do que o do vermicomposto, e que o de P, é semelhante. O vermicomposto aumentou os teores de Ca2+ e de matéria orgânica (MO), os valores de pH em CaCl2 e a CTC a pH 7. Com o aumento das doses de vermicomposto houve diminuição do C-ácidos húmicos e aumento do C-humina e com a calagem o C-total não aumentou mas houve diminuição do C-ácidos húmicos.