Características e atributos de Latossolos sob diferentes usos na região Oeste do Estado da Bahia

Abstract

Resumo -O objetivo deste trabalho foi avaliar os efeitos de diferentes usos da terra nas características e nos atributos de Latossolos da região Oeste do Estado da Bahia. Os Latossolos apresentavam texturas com fração areia amplamente predominante, e foram avaliados em áreas de cerrado, algodão, soja e feijão, no Município de Luís Eduardo Magalhães. A caracterização morfológica e a coleta de amostras de solos para avaliação dos atributos físicos e químicos por horizontes foram feitas em minitrincheiras, enquanto a avaliação da condutividade hidráulica saturada foi feita com permeâmetro de Guelph em duas profundidades: 0,0-0,20 e 0,20-0,40 m. Os Latossolos avaliados, além de uma estrutura maciça, apresentaram horizonte genético adensado, que, sob uso agrícola, torna-se mais compactado, espesso e superficial, e forma torrões quando revolvido. O uso agrícola reduz a condutividade hidráulica saturada dos Latossolos avaliados nas duas camadas, com exceção do cultivo de feijão.Termos para indexação: Cerrado, camada adensada, compactação de solo, condutividade hidráulica saturada, permeâmetro de Guelph, solos leves. Characteristics and attributes of Oxisols under different land uses in the western region of the state of Bahia, BrazilAbstract -The objective of this work was to evaluate the effects of different land uses on the characteristics and attributes of Oxisols in the western region of the state of Bahia, Brazil. The Oxisols had textures with largely predominant sand fraction, and they were evaluated in areas of cerrado, cotton, soybean, and common bean in the municipality of Luís Eduardo Magalhães. The morphological characterization and the collection of samples for evaluating soil physical and chemical attributes of horizons were carried out in small trenches, while the evaluation of field saturated hydraulic conductivity was done using the Guelph permeameter at two depths: 0.0 to 0.20 and 0.20 to 0.40 m. The evaluated Oxisols, besides their massive structure, showed a dense genetic horizon, which, under agricultural use, becomes more compacted, thick, and shallow, forming clods when plowed. Agricultural use reduces the saturated hydraulic conductivity of the evaluated Oxisols in both layers, except for common bean cultivation.

Influence of Land Use and Land Cover on Hydraulic and Physical Soil Properties at the Cerrado Agricultural Frontier

“…The general trends showed higher values of ρ a and lower values of φ tot in agriculture areas compared to native vegetation, revealing that soils under agricultural land use are slightly compacted in Western Bahia. This is in line with Fontana et al [48], who found ρ a in agriculture areas in the region of Luis Eduardo Magalhães equal or above 1.52 g cm −3 . Cunha et al [46] also found increased ρ a in different crop areas with different periods of cultivation, demonstrating that duration of land use also has an influence on soil structure.…”

“…The sand fraction is predominant in the granulometric composition of the soils, the clay content varies between 10% and 41% and the silt fraction presents the lower values, typically below 4% (Figure 2). This granulometric composition is the result of the high rate of weathering during the genesis of these soils and the soil source material-in this case, the sandstones of the Urucuia Formation [45][46][47][48].…”

“…Cunha et al [46] also found increased ρ a in different crop areas with different periods of cultivation, demonstrating that duration of land use also has an influence on soil structure. Naturally, the Cerrado Western Bahia soils present a cohesive sub-surface horizon [46,[48][49][50], making it more susceptible to compaction by grazing, mechanization and management applied at the soil surface. This transitional or subsurface horizon was observed and characterized by a slight increase in ρ a , generally within 10-30 cm [48].…”

“…Naturally, the Cerrado Western Bahia soils present a cohesive sub-surface horizon [46,[48][49][50], making it more susceptible to compaction by grazing, mechanization and management applied at the soil surface. This transitional or subsurface horizon was observed and characterized by a slight increase in ρ a , generally within 10-30 cm [48]. Indeed, our results show the natural cohesive sub-surface in the CDO and FOR areas (Figure 4b), and the intensification of the increase of ρ a in agriculture land uses.…”

Dry Mass Accumulation, Nutrients and Decomposition of Cover Plants

“…The southwest region of Piauí is part of the Brazilian agricultural frontier called MATOPIBA (Maranhão, Tocantins, Piauí and Bahia), which currently is in large agricultural expansion and intensification of land use for the cultivation of grains, fibers, energy materials, perennial crops and irrigated agriculture (Fontana et al, 2016). Despite the great productive potential, many technical-scientific recommendations applied to the soils come from regions with different edaphoclimatic conditions.…”