Combined legume and non-legume residues management improve soil organic matter on an Oxisol in Brazil
12/Dec/2022
ABSTRACT Understanding soil organic matter (SOM) dynamics in production systems on tropical soils is necessary to guide strategies to increase SOM formation. This study aimed to evaluate soil carbon (C) dynamics by combining applications of different plant residues used on tropical soils. An incubation study was carried out with and without adding millet (Pennisetum americanum) residues combined with six crop residues (legumes and non-legumes); and one additional treatment with only millet residue. Higher C-CO2 fluxes recorded in jack bean, sunflower […]
Aggregation rate as a function of soil organic matter in heavy clayey Ferralsols
16/Sep/2022
ABSTRACT Heavy clayey Ferralsols are known for their high capacity to form water-stable macroaggregates. However, little is known about how different size classes of macroaggregates exchange mass with increasing organic matter content. This study aimed to characterize and detail aggregation dynamics with increasing organic matter content in these soils. Profiles of three heavy clayey Ferralsols were sampled to isolate the role of organic matter on the stability of aggregates. In this sampling scenario, a conceptual model was established to calculate […]
Liming and grazing intensities effects on soil mineral nitrogen throughout the pasture cycle in a subtropical integrated crop-livestock system
06/Apr/2022
ABSTRACT Grazing intensity is a preponderant factor for the success of integrated crop-livestock systems (ICLS). Management of grazing intensity impacts soil organic matter (SOM) dynamics, soil reacidification process, and amount and quality of residues added to the ICLS. Consequently, the soil mineral nitrogen (N) forms may present different behavior throughout the pasture cycle, because they are directed linked to SOM and soil acidity dynamics. This study aimed to evaluate the impact of grazing intensities and liming in the temporal variation […]
Lime and phosphogypsum application management: changes in soil acidity, sulfur availability and crop yield
13/Aug/2021
ABSTRACT Oxisols ( Latossolos ) are widely distributed in tropical zones and generally characterized by high levels of surface and subsurface acidity. In Brazil, most Oxisols are managed under no-till conditions with surface application of acidity amendments. This study aimed to evaluate lime application strategies (incorporated and surface) for achieving the desired soil base saturation (BS%) levels (44, 60, 70, and 90 %) and the effect of phosphogypsum + lime application on soil chemical properties as well as wheat and […]
Effectiveness of Five Biosolids as Nitrogen Sources to Produce Single and Cumulative Ryegrass Harvests in Two Australian Soils
06/Jun/2016
ABSTRACT Biosolids have been produced by various stabilization processes of sewage sludge, but little attention has been given to the effects of such treatments on their effectiveness to supply nitrogen for plant growth. Here, we investigated these effects by cultivating Lolium perenne (ryegrass) in two Australian soils, a sandy Spodosol and a clayey Oxisol. Biosolids stabilized by either aerobic digestion, composting, CaO-liming, 250 oC heat-drying or solar irradiation of domestic sewage sludge were applied to soils at 10 increasing rates […]
Surface Complexation Modeling in Variable Charge Soils: Prediction of Cadmium Adsorption
01/Sep/2015
ABSTRACT Intrinsic equilibrium constants for 22 representative Brazilian Oxisols were estimated from a cadmium adsorption experiment. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. Intrinsic equilibrium constants were optimized by FITEQL and by hand calculation using Visual MINTEQ in sweep mode, and Excel spreadsheets. Data from both models were incorporated into Visual MINTEQ. Constants estimated by FITEQL and incorporated in Visual MINTEQ software failed to predict observed data accurately. However, FITEQL raw output data […]
Carbon and nitrogen in the particle size fractions of soil organic matter in crop systems under no-tillage
01/Jun/2014
Soil quality in no-till systems is related to the crop systems and may be evaluated through particulate organic matter (>53 ∝m) stock due to the functionality this property provides to the soil and its sensitivity to management practices. Aiming to assess soil quality no-till crop systems, this study was carried out through a long-term experiment (21 years) in a Latossolo Vermelho distrófico típico (typical Oxisol) in Ponta Grossa, PR, Brazil. Six crop systems were assessed. Wheat-TR (Triticum aestivum L.), soybean-SO […]
Plant-available soil water capacity: estimation methods and implications
01/Apr/2014
The plant-available water capacity of the soil is defined as the water content between field capacity and wilting point, and has wide practical application in planning the land use. In a representative profile of the Cerrado Oxisol, methods for estimating the wilting point were studied and compared, using a WP4-T psychrometer and Richards chamber for undisturbed and disturbed samples. In addition, the field capacity was estimated by the water content at 6, 10, 33 kPa and by the inflection point […]
Model to predict water infiltration and soil moisture profile
01/Apr/2013
Soil water infiltration modeling is an important tool to predict soil water redistribution, soil erosion, aquifer recharge and aquifer contamination. This paper presents a model to simulate soil water infiltration (GAML-c), based on the Green-Ampt-Mein-Larson (GAML) model that provides a description of the geometry and advance of the wetting front in the soil. Experimental infiltration tests were performed in Red-Yellow Oxisol (LVA). GAML-c was evaluated in four scenarios: considering hydraulic conductivity (K0) equal to the stable infiltration rate (Tie) and […]
Soil management systems in the recovery of a degraded pasture in Rondônia
01/Feb/2013
In the Amazon region, pastures provide a satisfactory grass yield in the first years. Over time, overgrazing by livestock, the lack of pasture maintenance and choice of regionally unsuitable forage species can lead to soil degradation. The objective of this study was to evaluate the effect of different soil management systems on some soil physical properties of a Red-Yellow Oxisol (LVA) under degraded pasture, in the State of Rondônia (RO). The soil management systems were T = control; G = […]