Humic Haplustox under different land uses in a high altitude environment in the Agreste region of Pernambuco, Brazil
| Autor: | Marcelo Metri Corrêa, Mateus Rosas Ribeiro, Valdomiro Severino de Souza Júnior, Jane Kelly Silva Araujo, Izabel Cristina de Luna Galindo |
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| Rok vydání: | 2014 |
| Předmět: |
uso do solo
estabilidade de agregados highland soils solos de altitude Soil Science Soil science Pasture substâncias húmicas Cation-exchange capacity microbial biomass C lcsh:Agriculture (General) Cropping system aggregate stability Total organic carbon geography geography.geographical_feature_category Land use humic substances C microbiano land use lcsh:S1-972 Agronomy Soil water Humin Environmental science Soil horizon Agronomy and Crop Science |
| Zdroj: | Revista Brasileira de Ciência do Solo, Vol 38, Iss 4, Pp 1337-1349 (2014) Revista Brasileira de Ciência do Solo v.38 n.4 2014 Revista Brasileira de Ciência do Solo Sociedade Brasileira de Ciência do Solo (SBCS) instacron:SBCS |
| ISSN: | 0100-0683 |
| DOI: | 10.1590/s0100-06832014000400029 |
| Popis: | The Garanhuns Plateau in the Agreste region of the State of Pernambuco, Brazil is characterized by humid climatic conditions due to orographic rains, unlike the surrounding semiarid region. These soils are subjected to intense agricultural use and are extremely important for the regional economy. This study was carried out in the municipality of Brejão in the Agreste region with the aim of assessing changes in humic Haplustox soils subjected to different land uses. Four plots with different vegetation covers (native forest, secondary shrubby vegetation (capoeira), traditional cropping system, and planted pasture) were selected, and samples were taken from a soil profile and four small pits surrounding it at each site. Physical and chemical properties were assessed, including aggregate stability, humic organic fractions, and a microbiological evaluation through determination of basal respiration, microbial biomass carbon, and metabolic quotient. The soils under study showed physical and chemical properties typical of a Haplustox, such as low nutrient content, low cation exchange capacity, and high levels of acidity and Al saturation. The total organic carbon (TOC) contents were high regardless of the type of land use. Aggregates < 2 mm were dominant in all the conditions under study. The TOC content was higher in the soil under capoeira, 43.91 g kg-1 on the surface, while 34.36 and 33.43 g kg-1 of TOC were observed in the first layer of forest and pasture soils, respectively. While the microbial biomass C (MBC) was greater than 700 mg kg-1 in the forest and pasture areas (in the 0-5 cm layer), and 588 mg kg-1 in the soil under capoeira, these numbers were not statistically different. In the cultivated soil area, there was a reduction of around 28 % in TOC and MBC contents. Agricultural activity contributed to degradation of the humic horizon, as can be seen from a significant decrease in the TOC and changes in the relative distribution of the humic fractions. In contrast, aggregate stability was not altered as a function of the different land uses; the soil under planted pasture and capoeira were similar to the soil under native forest. Humin was the most important humified fraction for C reserves, contributing over 40 % of the TOC in these soils. |
| Databáze: | OpenAIRE |
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