Assinatura magnética na avaliação da compactação do solo
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Data
2018-11-21
Autores
Cortez, Lucas Aguilar [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A compactação é um dos principais fenômenos físicos que causam degradação dos solos e perdas de produtividade das culturas. Identificar por meio de técnicas indiretas, rápidas e de baixo custo, locais e umidade do solo com maiores potenciais de compactação é ferramenta importante para o uso sustentável do solo. A proposta é entender o comportamento da compactação do solo com diferentes composições mineralógicas e cobertura vegetal, e com o uso da assinatura magnética do solo (SM) direcionar o manejo em locais e umidade que não condiciona compactação. Foram construídas curvas de compactação pelo ensaio de Proctor para três solos com diferentes teores de ferro, Latossolo Vermelho distrófico (LVd); Latossolo Vermelho eutroférrico (LVef); Neossolo Quartzarênico órtico distrófico (RQod). Também foram avaliadas a granulometria, composição mineralógica e SM. Para cada tipo de solo foi testado o grau de compactação em seis diferentes teores de água (6, 12, 18, 24, 30 e 36%) e profundidade (0,0-0,1 m; 0,1 – 0,2 m; 0,2 – 0,3 m; 0,3 – 0,4 m). Foi avaliado também o efeito da cobertura vegetal na qualidade física do solo considerando 4, 8 e 12 t palha/ha. Com teores de água no solo até 18% quando manejados com a mesma energia de compactação, solos com assinatura magnética inferior a 11x10-6m3/kg1 compactam até 24% a mais do que solos com valores acima de 50x10-6m3/kg1. A assinatura magnética do solo viabilizou a construção de mapas de manejo especifico, indicando locais com suscetibilidades distintas à compactação em função da umidade. A cobertura vegetal apresentou importante papel na melhoria estrutural do solo, diminuindo em todos os solos o potencial de compactação. O efeito amortecedor da palha reduziu a densidade do solo em 23% no LVd quando manejado a 6% de umidade e 19% no RQod, a 12% de umidade.
Compaction is one of the major physical phenomena that cause soil degradation and crop yield losses. Identifying through indirect techniques, fast and low cost, local and soil moisture with higher compaction potentials is an important tool for sustainable soil use. The proposal is to understand the behavior of soil compaction with different mineralogical compositions and vegetation cover, and with the use of the magnetic signature of the soil (SM) to direct the management in places and humidity that does not condition compaction. Compaction curves were constructed by the Proctor test for three soils with different iron contents, Dystrophic Red Latosol (LVd); Eutrophic Red Latosol (LVef); Dystrophic Orthodox quartzenosis (RQod). The granulometry, mineralogical composition and SM were also evaluated. For each soil type, the degree of compaction was tested in six different water contents (6, 12, 18, 24, 30 and 36%) and depth (0,0-0,1 m, 0,1 - 0,2 m; 0.2-0.3 m; 0.3-0.4 m). The effect of the vegetation cover on the physical quality of the soil considering 4, 8 and 12 t straw / ha was also evaluated. With soil water contents up to 18% when handled with the same compaction energy, soils with a magnetic signature less than 11x10-6m3 / kg1 compact up to 24% more than soils with values above 50x10-6m3 / kg1. The magnetic signature of the soil allowed the construction of specific management maps, indicating places with different susceptibilities to compaction as a function of humidity. The vegetation cover had an important role in the soil structural improvement, reducing in all soils the compaction potential. The straw damping effect reduced soil density by 23% in LVd when driven at 6% moisture and 19% at RQod at 12% moisture.
Compaction is one of the major physical phenomena that cause soil degradation and crop yield losses. Identifying through indirect techniques, fast and low cost, local and soil moisture with higher compaction potentials is an important tool for sustainable soil use. The proposal is to understand the behavior of soil compaction with different mineralogical compositions and vegetation cover, and with the use of the magnetic signature of the soil (SM) to direct the management in places and humidity that does not condition compaction. Compaction curves were constructed by the Proctor test for three soils with different iron contents, Dystrophic Red Latosol (LVd); Eutrophic Red Latosol (LVef); Dystrophic Orthodox quartzenosis (RQod). The granulometry, mineralogical composition and SM were also evaluated. For each soil type, the degree of compaction was tested in six different water contents (6, 12, 18, 24, 30 and 36%) and depth (0,0-0,1 m, 0,1 - 0,2 m; 0.2-0.3 m; 0.3-0.4 m). The effect of the vegetation cover on the physical quality of the soil considering 4, 8 and 12 t straw / ha was also evaluated. With soil water contents up to 18% when handled with the same compaction energy, soils with a magnetic signature less than 11x10-6m3 / kg1 compact up to 24% more than soils with values above 50x10-6m3 / kg1. The magnetic signature of the soil allowed the construction of specific management maps, indicating places with different susceptibilities to compaction as a function of humidity. The vegetation cover had an important role in the soil structural improvement, reducing in all soils the compaction potential. The straw damping effect reduced soil density by 23% in LVd when driven at 6% moisture and 19% at RQod at 12% moisture.
Descrição
Palavras-chave
Pedometria, Suscetibilidade magnética, Cobertura vegetal, Mineralogia do solo