Efeito de sistemas de manejo na estabilidade de agregados de um Nitossolo Vermelho
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Data
2005-12-01
Autores
Lacerda, Nilda B.
Zero, Vânia M. [UNESP]
Barilli, Juliana [UNESP]
Moraes, Maria Helena [UNESP]
Bicudo, Silvio José [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Engenharia Agrícola (SBEA)
Resumo
Com o objetivo de avaliar o efeito do manejo do solo na estabilidade de agregados de um Nitossolo Vermelho distroférrico, localizado na Fazenda Experimental Lageado da FCA/UNESP, em Botucatu - SP, amostraram-se, em outubro de 2001, três sistemas de manejo de solo: (i) mata (MA), (ii) preparo convencional por 10 anos seguido de semeadura direta por 12 anos (PC/SD) e (iii) preparo convencional por 22 anos (PC), em quatro camadas: 0,0-0,10; 0,10-0,20; 0,20-0,30 e 0,30-0,40 m. O delineamento experimental empregado foi o inteiramente casualizado, com três repetições. As amostragens foram feitas após a cultura do milho (safra 2000-2001). As amostras foram submetidas às análises físicas e químicas, e as médias, comparadas pelo teste de Tukey. O diâmetro médio ponderado dos agregados (DMP), o índice de estabilidade dos agregados (IEA) e a percentagem de agregados em classes de diâmetro médio foram obtidos com os resultados do peneiramento obtidos pelo método por via úmida. O diâmetro médio ponderado e o índice de estabilidade dos agregados foram menores para o preparo convencional do solo. Os três sistemas de manejo apresentaram maior percentagem de agregados com diâmetro entre 7,93 e 2,00 mm. A substituição do preparo convencional pela semeadura direta favoreceu a estabilidade dos agregados do solo. O diâmetro médio ponderado, o índice de estabilidade de agregados e a percentagem de agregados por classe de diâmetro médio evidenciaram diferenças entre os sistemas de manejo do solo.
The purpose of this work was to evaluate the effect of soil management systems in the aggregate stability. The soil of the experimental site, classified as an Alfisol, according to the Brazilian System of Soil Classification, is located at the Lageado Experimental Farm, FCA/UNESP, in Botucatu - SP (Brazil). The effect of management practices was evaluated in the following treatments: native forest (MA), continuous conventional tillage for ten years followed by no-tillage for twelve years (PC/SD) and continuous conventional tillage for twenty two years (PC). The soil was sampled in four layers: 0.0-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m. Soil samples were collected from each treatment in October 2001. The experimental design was completely randomized with three replicates. The wet soil aggregate stability was expressed as mean weight diameter (DMP), aggregate stability index (IEA) and percentage of aggregate size class. The DMP and the IEA were greater to the soil under native forest and conventional tillage/no-tillage. The three management systems presented larger aggregate percentage with diameter between 7.93 and 2.00 mm. The change from conventional tillage to no-tillage improved the soil aggregate stability. The mean weight diameter, the aggregate stability index and the percentage of aggregate size class evidenced differences among the soil management systems.
The purpose of this work was to evaluate the effect of soil management systems in the aggregate stability. The soil of the experimental site, classified as an Alfisol, according to the Brazilian System of Soil Classification, is located at the Lageado Experimental Farm, FCA/UNESP, in Botucatu - SP (Brazil). The effect of management practices was evaluated in the following treatments: native forest (MA), continuous conventional tillage for ten years followed by no-tillage for twelve years (PC/SD) and continuous conventional tillage for twenty two years (PC). The soil was sampled in four layers: 0.0-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m. Soil samples were collected from each treatment in October 2001. The experimental design was completely randomized with three replicates. The wet soil aggregate stability was expressed as mean weight diameter (DMP), aggregate stability index (IEA) and percentage of aggregate size class. The DMP and the IEA were greater to the soil under native forest and conventional tillage/no-tillage. The three management systems presented larger aggregate percentage with diameter between 7.93 and 2.00 mm. The change from conventional tillage to no-tillage improved the soil aggregate stability. The mean weight diameter, the aggregate stability index and the percentage of aggregate size class evidenced differences among the soil management systems.
Descrição
Palavras-chave
diâmetro médio ponderado, índice de estabilidade de agregados, semeadura direta, mean weight diameter, aggregate stability index, and no-tillage
Como citar
Engenharia Agrícola. Associação Brasileira de Engenharia Agrícola, v. 25, n. 3, p. 686-695, 2005.