Carbon and Nitrogen Stocks and Humic Fractions in Brazilian Organosols
AUTOR(ES)
Valladares, Gustavo Souza, Pereira, Marcos Gervasio, Benites, Vinícius de Melo, Anjos, Lúcia Helena Cunha dos, Ebeling, Adierson Gilvani, Guareschi, Roni Fernandes
FONTE
Rev. Bras. Ciênc. Solo
DATA DE PUBLICAÇÃO
03/11/2016
RESUMO
ABSTRACT Despite limited geographic expression of Organosols in Brazil, their high carbon storage capacity and natural environmental vulnerability justifies further studies on C and N stocks in these soils and their relationship to the nature of organic matter. Evaluation of physical and chemical properties of organic soils and their ability to store C is important so as to develop sustainable management practices for their preservation. The objectives of the study were to measure the total organic carbon stock (OCst), total nitrogen stock (Nst), and humic fractions in Organosols from different environments and regions of Brazil, and to correlate the data with soil chemical (pH, P, K, Ca2+, Mg2+, Al3+, H+Al, CEC, V) and physical properties (soil bulk density, Bd; organic matter density, OMd; total pore space, TPS; minimum residue, MinR; and proportion of mineral matter, MM), and degree of organic matter decomposition (rubbed fiber content; pyrophosphate index, PyI; and von Post index). For that purpose, 18 Organosol profiles, in a total of 49 horizons, were sampled under different land usage and plant coverage conditions. The profiles were located in the following Brazilian states - Alagoas, Bahia, Distrito Federal, Espírito Santo, Mato Grosso do Sul, Minas Gerais, Paraná, Rio de Janeiro, Rio Grande do Sul, Santa Catarina, and São Paulo. The OCst and Nst varied significantly among horizons and profiles. The Organosols exhibited, on average, 203.59 Mg ha-1 OCst and 8.30 Mg ha-1 Nst, and the highest values were found in profiles with pasture usage. The content of the humic fraction (humin, HUM; fulvic acid, FAF; and humic acid, HAF) and C storage varied in the soil horizons and profiles according to the degree of decomposition and other factors of soil formation. The OCst, Nst, OMd and the C stocks in the humic fractions were positively correlated. The values of acidity were lower in the soils with higher contents of mineral material, and low pH values were related to a high C/N ratio. The OCst and Nst were correlated with different soil properties, the most important being the degree of soil organic matter decomposition, which was inversely correlated.
Documentos Relacionados
- PHYSICAL FRACTIONATION AND CARBON AND NITROGEN STOCKS IN SOIL AFTER POULTRY WASTE APPLICATIONS
- Carbon and nitrogen stocks of an arenosol under irrigated fruit orchards in semiarid Brazil.
- Soil carbon stocks and labile fractions of organic matter under agroforestry system in breast of pernambucan altitude
- Carbon in Humic Fractions of Organic Matter in Soil Treated with Organic Composts under Mango Cultivation
- Bacterioplankton Growth on Fractions of Dissolved Organic Carbon of Different Molecular Weights from Humic and Clear Waters