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Sparovek,G.; Camargo,O. A.. |
The precise sampling of soil, biological or micro climatic attributes in tropical forests, which are characterized by a high diversity of species and complex spatial variability, is a difficult task. We found few basic studies to guide sampling procedures. The objective of this study was to define a sampling strategy and data analysis for some parameters frequently used in nutrient cycling studies, i. e., litter amount, total nutrient amounts in litter and its composition (Ca, Mg, Κ, Ν and P), and soil attributes at three depths (organic matter, Ρ content, cation exchange capacity and base saturation). A natural remnant forest in the West of São Paulo State (Brazil) was selected as study area and samples were collected in July, 1989. The total... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tropical forest; Utter; Soil nutrients; Variability. |
Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06831997000400014 |
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Sparovek,G.; Jong Van Lier,Q.. |
Although the criteria for defining erosion tolerance are well established, the limits generally used are not consistent with natural, economical and technological conditions. Rates greater than soil formation can be accepted only until a minimum of soil depth is reached, provided that they are not associated with environmental hazard or productivity losses. A sequence of equations is presented to calculate erosion tolerance rates through time. The selection of equation parameters permits the definition of erosion tolerance rates in agreement with environmental, social and technical needs. The soil depth change that is related to irreversible soil degradation can be calculated. The definition of soil erosion tolerance according to these equations can be... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Erosion tolerance; Soil depth change; Land use planning. |
Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06831997000300016 |
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Salviano,A. A. C.; Vieira,S. R.; Sparovek,G.. |
O trabalho foi desenvolvido numa área de produção comercial de cana-de-açúcar, situada no município de Piracicaba (SP), numa associação de Podzólico Vermelho-Amarelo + solo litólico, no período de novembro de 1994 a março de 1995. Essa área vem sendo explorada com cana-de-açúcar há, aproximadamente, 30 anos e apresentava diversos sulcos de erosão. O objetivo deste trabalho foi caracterizar a variabilidade espacial de atributos de crotalária juncea (Crotalaria juncea L.) e de solo em uma área sob condições de erosão severa. A área foi arada e gradeada com incorporação de 4 t ha-1 de calcário, antes da semeadura a lanço de 30 kg ha-1 de semente de crotalária juncea. Uma parcela de 50 x 70 m foi amostrada de acordo com uma malha de 5 por 5 m, totalizando 140... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Solo degradado; Semivariograma; Adubo verde; Erosão. |
Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06831998000100016 |
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Sparovek,G.; Weill,M.M.; Ranieiri,S.B.L.; Schnug,E.; Silva,E.F.. |
By definition, erosion tolerance should consider the conservation of the soil as a natural resource essential for crop production. Erosion rates greater than soil renewal will cause soil depth loss. A minimum soil depth was defined as the depth in which the inputs (fertilizers, crop residues) and management technology (irrigation, improved genetic crop quality) were insufficient to prevent economic productivity loss. Thus, erosion rates greater than soil formation are acceptable only during the time in which the soil does not reach the minimum depth. We have defined this time period as life-time. The life-time concept was applied to the Ceveiro watershed (1,945 ha) located in a sugarcane growing region in the Southeast of Brazil Erosion rates were... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Erosion tolerance; Life-time. |
Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161997000300015 |
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