The hydraulic conductivity, determined as a function of the volumetric soil water content K(θ), is essential to solve, e.g., drainage problems. However, the results of different methods vary according to the different assumptions. The objective of this study was to compare direct field methods (Instantaneous Profile, Flux and Humidity) and indirect laboratory methods for estimating the hydraulic conductivity as a function of soil water content, K(θ). The experiment was carried out in Piracicaba, State of São Paulo (Brazil), with a […]

A method for determining soil hydraulic properties of a weathered tropical soil (Oxisol) using a medium-sized column with undisturbed soil is presented. The method was used to determine fitting parameters of the water retention curve and hydraulic conductivity functions of a soil column in support of a pesticide leaching study. The soil column was extracted from a continuously-used research plot in Central Oahu (Hawaii, USA) and its internal structure was examined by computed tomography. The experiment was based on tension […]

Inadequate land use and large buildings in rural areas are causing damages to the soil-climate environment, reducing productivity and thus expanding degraded areas. In view of this problem, this study evaluated the recovery of an Oxisol that had been treated with green manure, soil amendment, gypsum and pasture in the last 17 years. The quality of the structure was used as an indicator of soil recovery. The study was conducted in a completely randomized design with nine treatments and four […]

The retention in soil profiles of surface-applied mineral elements is crucial to maintain the water quality and reduce environmental and economic damages. This study evaluated: the mobility of potassium, calcium and magnesium, aluminum and organic matter contents and changes in pH in an Eutroferric Red Latosol under no-tillage, and the chemical oxygen demand (COD) of percolated water. Mobility was assessed in an undisturbed soil column with preserved structure and treated with mineral (100 kg ha-1) and organic (150 m3 ha-1) […]

Native pastures in southern Brazil are used for cattle and sheep grazing. The forage offer in the spring-summer season is greater than the animal requirement, so the forage left over is usually burned. Pasture burning mineralizes nutrients and leaves the soil bare, triggering water erosion. This study aimed to quantify total soil and water losses and P, K and NH4+ contents in the runoff water from an Oxisol with native pasture. In the treatments, the native pastures, were i) unburned […]

The aim of this study was to calibrate the CENTURY, APSIM and NDICEA simulation models for estimating decomposition and N mineralization rates of plant organic materials (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum, Stylosanthes guyanensis) for 360 days in the Atlantic rainforest bioma of Brazil. The models´ default settings overestimated the decomposition and N-mineralization of plant residues, underlining the fact that the models must be calibrated for use under tropical conditions. For example, the APSIM model simulated the decomposition of the […]

Given the scarcity of information in the literature and the importance of a proper management of organic waste in agriculture, this paper evaluated the effects of applying residues of the guava processing industry to an Ultisol, by evaluating changes in soil chemical properties, in the nutritional status of guava plants and fruit production. The residue rates applied in the orchard were established according to the residue N content and evaluated in a randomized block design with four replications, and the […]

The agricultural potential of Latosols of the Brazilian Cerrado region is high, but when intensively cultivated under inappropriate management systems, the porosity can be seriously reduced, leading to rapid soil degradation. Consequently, accelerated erosion and sedimentation of springs and creeks have been observed. Therefore, the objective of this study was to evaluate structural changes of Latosols in Rio Verde, Goiás, based on the Least Limiting Water Range (LLWR), and relationships between LLWR and other physical properties. Soil samples were collected […]

Several studies have confirmed the benefits of silicon (Si) for crop growth. The purpose of this study was to evaluate the effects of Si on the initial growth of coffee plants cv. Catuaí Vermelho. This study was carried out with potted plants grown in a greenhouse, without water deficiency. Dry matter partitioning of roots, stems and leaves as well as the chemical composition of plant tissues and soil and leaf gas exchange were evaluated in plants treated with 0 (control), […]

This study aimed to evaluate the impact of the eucalypt cultivation at different ages and of phytophysiognomy of the cerrado biome on total organic C stocks and its pools and to verify which one is more sensitive to land use changes. The study was conducted in Brasilia, Distrito Federal, in a Yellow Latosol under eucalyptus after three (PEUC-3), six (PEUC-6) and seven (PEUC-7) years of cultivation, and under savannah strict sensu, dense savannah and open grassland with scattered shrubs. In […]