Physical properties of dystrophic Red Latosol (Oxisol) under different agricultural uses

João Tavares Filho,Graziela Moraes De Cesare Barbosa,Adriana Aparecida Ribon

doi:10.1590/s0100-06832010000300034

João Tavares Filho, Graziela Moraes De Cesare Barbosa + Show 1 more

Open Access

https://doi.org/10.1590/s0100-06832010000300034

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Abstract

Obtaining information about soil properties under different agricultural uses to plan soil management is very important with a view to sustainability in the different agricultural systems. The aim of this study was to evaluate changes in certain indicators of the physical quality of a dystrophic Red Latosol (Oxisol) under different agricultural uses. The study was conducted in an agricultural area located in northern Paraná State. Dystrophic Red Latosol samples were taken from four sites featuring different types of land use typical of the region: pasture of Brachiaria decumbens (P); sugarcane (CN); annual crops under no-tillage (CAPD); and native forest (permanent conservation area) (control (C)). For each land use, 20 completely randomized, disturbed and undisturbed soil samples were collected from the 0-20 cm soil layer, to determine soil texture, volume of water-dispersible clay, soil flocculation (FD), particle density, quantity of organic matter (OM), soil bulk density (Ds), soil macroporosity (Ma) and microporosity (Mi), total soil porosity (TSP), mean geometric diameter of soil aggregates (MGD), and penetration resistance (PR). The results showed differences in OM, FD, MGD, Ds, PR, and Ma between the control (soil under forest) and the areas used for agriculture (P, CN and CAPD). The soils of the lowest physical quality were those used for CN and CAPD, although only the former presented a Ma level very close to that representing unfavorable conditions for plant growth. For the purposes of this study, the physical properties studied were found to perform well as indicators of soil quality.

Highlights

Caiuá sandstone soils cover approximately 3,000,000 ha in the north and northwest of the state of Paraná (Brazil)
The differences were 1.66 dag kg-1 between (C) and (P); 2.28 dag kg-1 between (C) and (CN); and 1.33 dag kg-1 between (C) and (CAPD). These results show that the mean absolute content of organic matter (OM) was most diminished in the soil under sugarcane (CN), with a mean absolute content of OM around 69% lower than in the soil under native forest (C)
In terms of the second hypothesis – that soil preparation affects floculação do solo (FD) – the results show that where land management is most intense (CN, CAPD), FD is the lowest

Summary

Introduction

Caiuá sandstone soils cover approximately 3,000,000 ha in the north and northwest of the state of Paraná (Brazil). Of this area, which accounts for 15 % of the state, 60 to 65 % is occupied by Latosols. The fertility of these soils is low and the physical properties enable infiltration and redistribution of water and oxygen. When used for agroforestry activities, the original properties undergo changes that tend towards a new state of equilibrium, which may affect soil and water conservation and crop production. The different soil management systems aim to create favorable conditions for crop development. If the soil conditions are not taken into consideration – whether the soil is moist and friable – and increasingly large and heavy machinery is used, together with highly intensive soil tillage and an inappropriate management of crop residues, the soil structure may be modified, resulting in increased compaction

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