Densidade relativa ótima de Latossolos Vermelhos para a produtividade de soja
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Data
2005-12-01
Autores
Beutler, Amauri Nelson [UNESP]
Centurion, José Frederido [UNESP]
Roque, Cassiano Garcia [UNESP]
Ferraz, Marcos Vieira [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
A compactação do solo tem causado decréscimos na produtividade de soja, e os valores de densidade do solo a partir dos quais a produtividade decresce são pouco conhecidos. Assim, este trabalho objetivou avaliar a produtividade de soja (cv. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48) em relação à densidade relativa (Dsr) de Latossolo Vermelho textura média (LVd) e argilosa (LVef). em 2001/2002, foi realizado um experimento em casa de vegetação, com amostras coletadas nos dois solos na camada de 0,0-0,2 m, peneirados a 4,0 mm, adubados e compactados em camadas de 3,0 cm, em vasos de 20 cm de altura e 25 cm de diâmetro. Foram estabelecidos quatro níveis de compactação e dois de água no solo (tensão de 0,01 e 0,05 MPa), com três repetições. A soja foi semeada em novembro (duas plantas por vaso) e irrigada duas vezes ao dia. No segundo experimento, no campo (2002/2003), utilizou-se apenas o LVd que foi compactado por meio de passadas de trator com quatro pneus de mesma largura, estabelecendo-se cinco níveis de compactação, com quatro repetições. A soja foi semeada, em dezembro de 2002, no espaçamento de 0,45 m entre linhas e 20 plantas por metro. Foram determinadas a densidade do solo (Ds) e a Ds máxima pelo teste de Proctor, sendo a Dsr obtida por divisão da Ds pela Ds máxima. Na colheita, foi avaliada a produtividade de grãos. A Dsr ótima para a produtividade de soja, em casa de vegetação, foi superior no Latossolo Vermelho eutroférrico argiloso (0,84), comparada à do Latossolo Vermelho caulinítico de textura média (0,75), na tensão de água no solo de 0,01 MPa. No campo, a Dsr ótima para soja foi de 0,80.
Soil compaction has led to reduced soybean yields, but the critical bulk density above which the yield decreases are poorly documented. Thus, this work aimed to evaluate the soybean yield (cv. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48) in relation to the relative bulk density (Dsr) of a sandy loam (LVd) and a clayey Oxisol (LVef). A greenhouse experiment was carried out in 2001/02 with samples collected at the 0.0-0.2 m layer, sifted through a 4.0 mm sieve, fertilized and compacted in 0.03 m layers in 0.20 high and 0.25 m diameter pots. Four compaction and two water content levels (tension of 0.05 and 0.01 MPa) were evaluated in three replications. Soybean was sown in November (two plants per pot) and irrigated twice a day. In the second experiment on the field (2002/2003), only LVd was used and compacted by driving a 11 Mg tractor with four equally wide (0.40 m) tires, establishing five compaction levels, with four replications. Soybean was sown in December 2002, spaced 0.45 m between lines and 20 plants per meter. The bulk density (Ds) and maximum Ds was determined by the Proctor test, and the Dsr was obtained by dividing Ds by the maximum Ds. The soybean yield was evaluated at harvest. Under a soil water tension of 0.01, the optimum Dsr for soybean yield under greenhouse conditions was greater in the clayey eutroferric Oxisol (0.84) compared to the clay loam caulinitic Oxisol (0.75). The optimum Dsr for field soybean yield was 0.80.
Soil compaction has led to reduced soybean yields, but the critical bulk density above which the yield decreases are poorly documented. Thus, this work aimed to evaluate the soybean yield (cv. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48) in relation to the relative bulk density (Dsr) of a sandy loam (LVd) and a clayey Oxisol (LVef). A greenhouse experiment was carried out in 2001/02 with samples collected at the 0.0-0.2 m layer, sifted through a 4.0 mm sieve, fertilized and compacted in 0.03 m layers in 0.20 high and 0.25 m diameter pots. Four compaction and two water content levels (tension of 0.05 and 0.01 MPa) were evaluated in three replications. Soybean was sown in November (two plants per pot) and irrigated twice a day. In the second experiment on the field (2002/2003), only LVd was used and compacted by driving a 11 Mg tractor with four equally wide (0.40 m) tires, establishing five compaction levels, with four replications. Soybean was sown in December 2002, spaced 0.45 m between lines and 20 plants per meter. The bulk density (Ds) and maximum Ds was determined by the Proctor test, and the Dsr was obtained by dividing Ds by the maximum Ds. The soybean yield was evaluated at harvest. Under a soil water tension of 0.01, the optimum Dsr for soybean yield under greenhouse conditions was greater in the clayey eutroferric Oxisol (0.84) compared to the clay loam caulinitic Oxisol (0.75). The optimum Dsr for field soybean yield was 0.80.
Descrição
Palavras-chave
soil compaction, Soil management, Glycine max, compactação do solo, Manejo do solo, Glycine max
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 29, n. 6, p. 843-849, 2005.