Sustentabilidade estrutural de um solo na região do alto Paranapanema/SP, submetido a dois sistemas de cultivo
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Data
2007-01-26
Autores
Cardoso, Virgínia Maria Fontes [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os solos agricolas tem sofrido grande alteracao na sua estrutura devida a compressao causada pelo trafego de equipamentos pesados, muitas vezes com carga superior aquelas que eles podem suportar, principalmente quando se encontram em umidades acima do seu limite de plasticidade, e isto tem sido um fator determinante na obtencao da produtividade agricola. O presente trabalho teve por objetivos estudar o impacto do manejo e da rotacao de cultura sobre a sustentabilidade estrutural de solo localizado na Bacia do Alto Paranapanema, em areas da fazenda Buriti Mirim, areas 1 e 2, irrigadas com sistema de pivo central em Argissolo Acinzentado de textura franco arenosa. Dois sistemas de cultivo foram avaliados: Plantios Convencional e Direto. Os impactos foram conhecidos por meios da quantificacao das Pressoes de Contatos (PC) do parque de maquinas e de alteracoes estruturais avaliadas pela resistencia do solo a penetracao, medidas pelo o Indice de Cone (IC), Pressao de Preconsolidacao (Ðp), e outros indices fisicos relativos a massa e volume do solo. Para isso, foram elaborados mapas e modelos matematicos, para obter dados qualitativos e quantitativos do comportamento estrutural do solo. Obteve-se modelos de capacidade de suporte de carga do solo (CSCS) por meio do ajuste dos dados de Ðp, em funcao de U, utilizando-se do modelo exponencial ( 10(a bU ) p Ð = + ), proposto por Dias Junior. As avaliacoes foram realizadas nas camadas superficial (CS) do solo, de 0 a 0,10 m e subsuperficial ou camada de maxima resistencia mecanica (CMRM), defina pelo IC. Os resultados permitiram concluir que o impacto dos sistemas de cultivos alterou a estrutura dos solos agrícolas da Bacia do Alto Paranapanema, sendo que a rotação de cultura, após um período de 2 anos, não foi capaz de produziu reduções significativas nos valores de resistência do solo à penetração para minimizar os efeitos da compactação.
Agricultural soils have undergone high alterations in its structure because of the necessary use of heavy equipment with a higher axle load mainly when it is found in humid conditions higher than its plasticity limit. This has been a limiting agricultural productivity factor. The present work evaluated management and crop rotation impact over structural sustainability of soils from Alto Paranapanema watershed in areas 1 and 2 at Buriti Mirim farm irrigated with a pivot central system in frank sandy texture Grayish Argisoil. Two cultivation systems were evaluated: Convention Planting and Direct Planting. The impacts became known by means of Contact Pressure (CP) quantification of machinery and structural alterations evaluated by resistance to soil penetration measured by Cone Index (CI), Pre-consolidation Pressure (óp) and other physical indexes related to mass and volume of soil. Maps and mathematical models were done which allowed qualitative and quantitative evaluations of soil structural behavior. Soil load support capacity (SLSC) models were obtained by óp data adjustments according to U using exponential model ( 10(a bU ) p ó = + ) proposed by Dias Junior. The evaluations were performed on the superficial soil layer (SP), i.e., from 0 to 0,10 m and sub superficially, or on the layer of maximum mechanical resistance (CMRM) defined by CI. The results concluded that management impact altered agricultural soils at Alto Paranapanema but culture rotation after 2 years did not produce significant reductions on soil resistence values to penetration to minimize compactation effects.The areas cultivated with conventional planting showed a more intense compactation when compared to direct planting areas. Spatial variability maps of soil properties were important tools to localize compacted areas. CSCS models were able to identify the management system most affected layers. When one associates... (Complete abstract click electronic access below)
Agricultural soils have undergone high alterations in its structure because of the necessary use of heavy equipment with a higher axle load mainly when it is found in humid conditions higher than its plasticity limit. This has been a limiting agricultural productivity factor. The present work evaluated management and crop rotation impact over structural sustainability of soils from Alto Paranapanema watershed in areas 1 and 2 at Buriti Mirim farm irrigated with a pivot central system in frank sandy texture Grayish Argisoil. Two cultivation systems were evaluated: Convention Planting and Direct Planting. The impacts became known by means of Contact Pressure (CP) quantification of machinery and structural alterations evaluated by resistance to soil penetration measured by Cone Index (CI), Pre-consolidation Pressure (óp) and other physical indexes related to mass and volume of soil. Maps and mathematical models were done which allowed qualitative and quantitative evaluations of soil structural behavior. Soil load support capacity (SLSC) models were obtained by óp data adjustments according to U using exponential model ( 10(a bU ) p ó = + ) proposed by Dias Junior. The evaluations were performed on the superficial soil layer (SP), i.e., from 0 to 0,10 m and sub superficially, or on the layer of maximum mechanical resistance (CMRM) defined by CI. The results concluded that management impact altered agricultural soils at Alto Paranapanema but culture rotation after 2 years did not produce significant reductions on soil resistence values to penetration to minimize compactation effects.The areas cultivated with conventional planting showed a more intense compactation when compared to direct planting areas. Spatial variability maps of soil properties were important tools to localize compacted areas. CSCS models were able to identify the management system most affected layers. When one associates... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Solos - Compactação, Mecanica do solo, Fisica do solo, Soil mechanics, Stabilization of soils, Compaction of soils
Como citar
CARDOSO, Virgínia Maria Fontes. Sustentabilidade estrutural de um solo na região do alto Paranapanema/SP, submetido a dois sistemas de cultivo. 2007. xi, 121 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2007.