Atributos químicos do solo decorrentes da aplicação em superfície de calcário e gesso em sistema plantio direto recém-implantado
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Data
2008-04-01
Autores
Soratto, Rogério Peres [UNESP]
Crusciol, Carlos Alexandre Costa [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
Há interesse em implantar o sistema plantio direto em áreas anteriormente cultivadas no sistema convencional ou sob pastagem, corrigindo a acidez com calagem superficial após a implantação do sistema. Essa prática pode ser possível desde que não haja impedimento físico do solo ao crescimento radicular. Nesse sentido, o gesso é uma alternativa para diminuição da atividade do Al3+ e aumento da saturação por bases (V), principalmente Ca2+, nas camadas do subsolo, podendo ser utilizado como produto complementar ao calcário. Este trabalho objetivou avaliar as alterações dos atributos químicos do solo (pH CaCl2, H + Al, Al3+, Ca2+, Mg2+, S-SO4(2-), V e teor de micronutrientes catiônicos) decorrentes da aplicação de calcário e de gesso agrícola em superfície em sistema plantio direto recém-implantado em região de inverno seco. O experimento foi conduzido em um Latossolo Vermelho distroférrico de Botucatu (SP). O delineamento experimental foi em blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas foram constituídas por quatro doses de calcário dolomítico com PRNT de 71,2 % (0, 1.100, 2.700 e 4.300 kg ha-1), visando elevar a saturação por bases a 50, 70 e 90 %, respectivamente. As subparcelas foram constituídas pelas doses de gesso agrícola de 0 e 2.100 kg ha-1. Amostras de terra foram coletadas nas profundidades de 0-0,05, 0,05-0,10, 0,10-0,20, 0,20-0,40, 0,40-0,60 e 0-0,20 m, aos três, seis, 12 e 18 meses da aplicação dos produtos. A aplicação superficial de calcário diminuiu a acidez e elevou os teores de Ca e Mg trocável, principalmente nas camadas superficiais do solo. A aplicação de gesso agrícola aumentou os teores de Ca trocável e S-SO4(2-), e diminuiu os teores de Al no solo, contribuindo para que os efeitos da calagem superficial nas características químicas do solo alcançassem, de forma mais rápida, as camadas do subsolo. Os valores de saturação por bases obtidos na profundidade de 0-0,20 m com a calagem foram menores do que os estimados pelo método da elevação da saturação por bases, principalmente nas maiores doses, mesmo com a aplicação de gesso agrícola. A calagem em superfície não alterou os teores de micronutrientes na camada de 0-0,20 m de profundidade.
There is interest to establish the no-tillage system in areas cultivated previously with conventional tillage or pasture, with surface liming after system establishment. This practice is possible provided that there are no physical obstacles for root growth. Phosphogypsum is an alternative to decrease Al3+ and increase base saturation (BS), mainly Ca2+, in the subsoil, and can be used complementary to liming. The objective of this study was to evaluate the changes in chemical soil attributes (pH CaCl2, H + Al, Al3+, Ca2+, Mg2+, S-SO4(2-), BS, and content of cationic micronutrients) as affected by lime and phosphogypsum surface application in a recently established no-tillage system in dry-winter region. The experiment was carried out on a dystroferric Haplorthox, in Botucatu County, São Paulo State, Brazil. A randomized complete block design, in split-plot scheme and four replications, was used. The plots consisted of four dolomitic limestone rates (0; 1,100; 2,700; and 4,300 kg ha-1), intended to reach a BS to 50, 70 and 90 %, respectively. The subplots were represented by the absence or presence of phosphogypsum application (2,100 kg ha-1). Soil samples were collected 3, 6, 12, and 18 months after lime and phosphogypsum application, at depths of 0-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40, 0.40-0.60, and 0-0.20 m. Lime surface application reduced soil and increased exchangeable Ca and Mg contents, mainly in the top soil layers. Phosphogypsum application promoted increasing exchangeable Ca and S-SO4(2-) contents, and decreased exchangeable Al in the soil, favoring the effects of surface liming that influenced the subsoil layers more rapidly. Base saturation values obtained at a depth of 0-0.20 m with liming were lower than those estimated by BS method, mainly at the highest levels, even with phosphogypsum application. Surface liming did not influence micronutrient contents in the 0-0.20 m layer.
There is interest to establish the no-tillage system in areas cultivated previously with conventional tillage or pasture, with surface liming after system establishment. This practice is possible provided that there are no physical obstacles for root growth. Phosphogypsum is an alternative to decrease Al3+ and increase base saturation (BS), mainly Ca2+, in the subsoil, and can be used complementary to liming. The objective of this study was to evaluate the changes in chemical soil attributes (pH CaCl2, H + Al, Al3+, Ca2+, Mg2+, S-SO4(2-), BS, and content of cationic micronutrients) as affected by lime and phosphogypsum surface application in a recently established no-tillage system in dry-winter region. The experiment was carried out on a dystroferric Haplorthox, in Botucatu County, São Paulo State, Brazil. A randomized complete block design, in split-plot scheme and four replications, was used. The plots consisted of four dolomitic limestone rates (0; 1,100; 2,700; and 4,300 kg ha-1), intended to reach a BS to 50, 70 and 90 %, respectively. The subplots were represented by the absence or presence of phosphogypsum application (2,100 kg ha-1). Soil samples were collected 3, 6, 12, and 18 months after lime and phosphogypsum application, at depths of 0-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40, 0.40-0.60, and 0-0.20 m. Lime surface application reduced soil and increased exchangeable Ca and Mg contents, mainly in the top soil layers. Phosphogypsum application promoted increasing exchangeable Ca and S-SO4(2-) contents, and decreased exchangeable Al in the soil, favoring the effects of surface liming that influenced the subsoil layers more rapidly. Base saturation values obtained at a depth of 0-0.20 m with liming were lower than those estimated by BS method, mainly at the highest levels, even with phosphogypsum application. Surface liming did not influence micronutrient contents in the 0-0.20 m layer.
Descrição
Palavras-chave
acidez do solo, fertilidade do solo, calagem, lixiviação de íons, soil acidity, soil fertility, liming, ion leaching
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 32, n. 2, p. 675-688, 2008.