Physical quality of sandy soils subjected to different land uses

Autor: Edvania Aparecida Corrêa, Sergio dos Anjos Ferreira Pinto, Isabel Cristina Moraes
Rok vydání: 2016
Předmět:
Zdroj: Revista Brasileira de Geografia Física. 9
ISSN: 1984-2295
DOI: 10.5935/1984-2295.20160102
Popis: Nos ultimos 30 anos tem-se verificado no cenario nacional a expansao dos cultivos de cana-de-acucar especialmente em areas antes ocupadas por pastagens. No geral, a modificacao dos usos da terra ocasiona impactos nos atributos fisicos dos solos, restringindo o pleno desenvolvimento radicular e favorecendo o aumento dos processos erosivos e a degradacao dos solos. Neste sentido, o presente trabalho objetivou avaliar as caracteristicas fisicas dos solos arenosos submetidos ao uso com cana-de-acucar, pastagens e mata nativa secundaria. Foram coletadas amostras de solos na bacia hidrografica do corrego Monjolo Grande, Ipeuna/Sao Paulo. Foram realizadas analises granulometricas e obtidos os valores de densidade do solo e porosidade total. Tambem foram obtidos os valores de resistencia mecânica do solo a penetracao (RMP) e taxas de infiltracao. A analise granulometrica demonstrou que os solos possuem elevada proporcao de areia fina, denotando maior susceptibilidade aos processos erosivos. Quando da comparacao com as areas de mata nativa secundaria, a maior parte das areas com pastagens apresentaram RMP superior a 3 MPa, aumento da compactacao em subsuperficie com consequente aumento da densidade do solo e diminuicao da porosidade total. No entanto, o cultivo com cana-de-acucar realizado ha oito anos causou maiores modificacoes nos atributos fisicos dos solos que o uso realizado ha mais de quarenta anos com pastagens. Considerando a expansao da cultura de cana-de-acucar e os impactos deste uso nos atributos fisicos dos solos, torna-se necessaria a adocao de um adequado planejamento do uso da terra que considere as limitacoes fisicas de cada paisagem. Normal 0 false false false PT-BR /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:PT-BR;} A B S T R A C T In the last thirty years is checked the expansion of sugarcane crop especially in areas previously occupied by pastures. Overall, the change of land use causes impacts on the soil physical attributes, restricting ROOT DEVELOPMENT and favoring the increase in erosion and soil degradation. In this sense, the present study aimed to evaluate the physical characteristics of sandy soils used with sugarcane, pasture and secondary native forest. Soil samples were collected in the basin of the stream Monjolo Grande, Ipeuna / Sao Paulo. We perform size analysis and obtain the bulk density and total porosity. Also there were obtained the values of soil strength (SS) and infiltration rates. The grain size analysis showed that the soils have a high proportion of fine sand, showing increased susceptibility to erosion. When compared to the areas of secondary native forest, most of the areas with pasture presented SS greater than 3 MPa, increased soil compaction in the subsurface with a consequent increase in bulk density and decrease in total porosity. However, the cultivation of sugarcane carried out eight years ago caused major changes in the soil physical properties that the use with pastures held for more than forty years. Considering the expansion of sugarcane culture and the impact of this use on the soil physical attributes, it is necessary to adopt an appropriate planning of land use that consider the physical limitations of each landscape. Key words: sugarcane, pasture, soil degradation, soil strength
Databáze: OpenAIRE
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