Soil Biological, Chemical, and Physical Properties After a Wildfire Event in a Eucalyptus Forest in the Pampa Biome
17/jul/2018
ABSTRACT Wildfire events cause considerable environmental disturbance but few studies have examined changes in soil properties due to fire. This study aimed to assess the effect of a wildfire event on chemical, physical, and biological properties of the soil in a eucalyptus forest in the Pampa biome. Part of a seven-year-old eucalyptus forest was affected by a wildfire event that lasted for two days. Soil and plant litter sampling was performed in three areas: in the forest that was not […]
Ajmalicine Bioproduction in Catharanthus Roseus (L) G. Don Inoculated with Arbuscular Mycorrhiza and Fertilized with Nitrogen
17/jul/2018
ABSTRACT Catharanthus roseus (L) G. Don (Madagascar periwinkle) belongs to the Apocynaceace family and is widely spread throughout tropical and subtropical regions of the world. The plant produces several important alkaloids, such as ajmalicine and serpentine, which are used in the treatment of circulatory diseases. The potential of inoculation with arbuscular mycorrhizal fungi (AMF) and nitrogen fertilization to enhance the production of alkaloids was investigated in periwinkle. A greenhouse experiment was carried out to evaluate the effects of arbuscular mycorrhizal […]
Mineralogy, Micromorphology, and Genesis of Soils with Varying Drainage Along a Hillslope on Granitic Rocks of the Atlantic Forest Biome, Brazil
06/jul/2018
ABSTRACT Although the physical environment of the Atlantic Forest realm is well known, studies on the soil-landform relationships are fundamental to improve the management of soil resources to facilitate sustainable development. The purpose of this study was to evaluate a representative topossequence on the “Mares de Morros” landscape of deeply weathered regolith on leucocratic granite rocks and demi-orange convex slopes. The soils varied along the topossequence according to drainage and were classified as Acrudox, Pseudogleysol, and Epiaquent. The clay fraction […]
Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments
18/jun/2018
ABSTRACT Although ferruginous materials occur frequently in soils of tropical regions, information about the reversal of the hardening process of these materials is scarce. This study assessed the influence of different chemical treatments and periods of immersion on the reversibility of the hardening process of plinthite and petroplinthite in soils of the Araguaia River plain. Soil samples were collected from the plinthic horizons in 0.10 m high and 0.15 m diameter PVC cylinders and divided into subsamples with a rock […]
An Alert Regarding a Common Misinterpretation of the Van Genuchten α Parameter
18/jun/2018
ABSTRACT Among the equations available to describe the relation between matric potential and soil water content, the soil water retention function, the most commonly used is the equation proposed by Van Genuchten in his 1980 landmark paper. In soil physics literature, especially in Brazil, several authors relate the inverse of the Van Genuchten parameter α to the air-entry pressure. This study aimed to show this common interpretation to be erroneous, as 1/α corresponds to water contents lower than saturation. The […]
Geochemistry and Spatial Variability of Rare Earth Elements in Soils under Different Geological and Climate Patterns of the Brazilian Northeast
18/jun/2018
ABSTRACT Growth in the agricultural and industrial sectors has increased the demand for rare earth elements (REEs) in the production of technological devices and fertilizers. Thus, the accumulation of these elements in the soil has become an environmental concern. Here, we aim to determine the natural contents of REEs in soils derived from different parent materials and under climatic conditions ranging from humid to semi-arid. We then evaluate the influence of major elements and soil properties on the geochemistry of […]
Daycent Simulation of Methane Emissions, Grain Yield, and Soil Organic Carbon in a Subtropical Paddy Rice System
18/jun/2018
ABSTRACT The DayCent ecosystem model, widely tested in upland agroecosystems, was recently updated to simulate waterlogged soils. We evaluated the new version in a paddy rice experiment in Southern Brazil. DayCent was used to simulate rice yield, soil organic carbon (SOC), and soil CH4 fluxes. Model calibration was conducted with a multiple-year dataset from the conventional tillage treatment, followed by a validation phase with data from the no-tillage treatment. Model performance was assessed with statistics commonly used in modeling studies: […]
Surface Application of Lime on a Guava Orchard in Production
18/jun/2018
ABSTRACT Several complications can arise, either directly or indirectly, from implementation of measures to correct soil acidity in established fruit orchards, such as impaired roots, lower root volume, risk of plant infection, propagation of diseases, promotion of pest development (especially nematodes), and soil disaggregation and compaction. These factors can have a negative effect on crop yield. Therefore, it becomes critical to implement an effective method of neutralizing soil acidity, especially at the level of the tree roots. To assess the […]
Multinomial Logistic Regression and Random Forest Classifiers in Digital Mapping of Soil Classes in Western Haiti
18/jun/2018
ABSTRACT Digital soil mapping (DSM) has been increasingly used to provide quick and accurate spatial information to support decision-makers in agricultural and environmental planning programs. In this study, we used a DSM approach to map soils in western Haiti and compare the performance of the Multinomial Logistic Regression (MLR) with Random Forest (RF) to classify the soils. The study area of 4,300 km2 is mostly composed of diverse limestone rocks, alluvial deposits, and, to a lesser extent, basalt. A soil […]
Water Erosion in Oxisols under Coffee Cultivation
18/jun/2018
ABSTRACT Water erosion is one of the main environmental impacts of land use. When soil and water losses occur, nutrients essential for the growth and maintenance of plants are removed, with harmful outcomes on the sustainability of agriculture and the environment. In addition, they lead to other deleterious effects, such as sedimentation and eutrophication of water bodies. Estimation of soil losses due to water erosion in sub-basins is essential for prediction of soil degradation, especially in areas of semi-intensive cultivation, […]