ABSTRACT Brazilian Soil Classification System (SiBCS) adopts a hierarchical approach to classify soils using specific diagnostic attributes. Organossolos (Histosols) class is differentiated according to its genesis, especially because the parent material is organic, thus requiring diagnostic attributes that describe the unique properties of soil organic matter (SOM). This study aimed to propose the use of labile organic carbon and the C and N contents of humic fractions and their ratios for the family and series levels of the Brazilian Soil […]

ABSTRACT Application of pig manure (PM) in agriculture can influence the amount and composition of soil organic matter (SOM). This study evaluated the changes in contents and stock of C in chemical fractions of SOM and the chemical and spectroscopic composition of humic substances (HS) in a Typic Hapludult (Argissolo Vermelho-Amarelo) after ten years of PM application. Experimental area received 90 and 180 kg ha-1 of N in the form of pig slurry (PS90 and PS180) and pig deep litter […]

In the Earth’s carbon cycle, C stocks in the soil are higher than in vegetation and atmosphere. Maintaining and conserving organic C concentrations in the soil by specific management practices can improve soil fertility and productivity. The aim of this study was to evaluate the impact of agricultural management techniques and influence of water regime (flooded or drained) on the structure of humic substances by excitation/emission matrix fluorescence. Six samples of a Planosol (Planossolo by the Brazilian System of Soil […]

In the soil, forms and content of water-soluble carbon (WSC) are influenced by factors such as organic matter quality and content, soil acidity, nutrient availability, mineralogy, and aspects related to the microbial community. This study aimed to evaluate forms and quantities of carbon (C) in leachates from Latosols (Oxisols) with different Fe contents, amended with lime and/or phosphorus. Samples of mesoferric Red Latosol (LV1) and hypoferric Red Latosol (LV2) were collected in the Rio das Mortes wathershed, state of Minas […]

A long-term field trial was carried out in the Jaboticabal county, São Paulo State. with the objective of estimating production system effects on the soil organic carbon and soil organic matter fractions. The tested treatments were corn under conventional sowing in the summer and no-tillage in the winter (C-Mi-P), maize under direct sowing in the summer and no-tillage in the winter (D-Mi-P), maize under direct sowing in the summer, Mucuna aterrina as green manure in the winter (D-Mi-Mu), maize under […]

A long-term field trial was carried-out in Jaboticabal (SP) to estimate the effect of production systems on soil nitrogen and soil organic matter fractions. The treatments tested were corn in conventional sowing in summer and no tillage in winter (C-Mi-P), maize in direct sowing in summer and no tillage in winter (D-Mi-P), maize in direct sowing in summer, Mucuna aterrina as green manure in winter (D-Mi-Mu), maize in direct sowing in summer, Cajanus cajan as green manure in winter (D-Mi-Gu), […]

This study evaluated the molecular weight (mw) as well as the proportions of humic and fulvic acid fractions in humic substances (H5) extracted with 0.1 M NaOH and a chelating (Chelex 100 chelating ion exchange resins) (Na form), via High-Performance Size Exclusion Chromatography (HPSEC). Samples of a Dusky Red Latosol were collected from three areas: under orange-cultivated forest with and without liming. Standards of sodium polystyrene sulfonate and acetone were used to calibrate the molecular weight and retention time ratio. […]

Six calcareous soil profiles (P1, P2, P3, P4, P5 and P6) were investigated with regard to their main characteristics of soil organic matter related to structural organization. The effect of degrading processes on these soils was also considered, mainly under intensive cultivation. Based on morphological in situ observation and analytical data, the profiles P1 e P2 showed organic matter with an advanced level of evolution presenting reasonable amounts of low polymerized materials (fulvic acids). Conversely, profiles P3, P4, P5 e […]