Millet can be used as cover crop and enhance nutrient cycling in low-fertility soils. The aim of this study was to evaluate the decomposition rate and nutrient release from shoot residues of millet and sorghum left on the soil surface. The treatments consisted of pearl millet (cultivars ENA 2 and BRS 1501), and sorghum (hybrid BRS 310) plants. After cutting, at the end of the cycle, the shoot samples were placed in decomposition bags distributed on the plot surface. Plant […]

The limited availability of low-salinity water in Brazilian semiarid region causes producers to use water of moderate to high salinity for irrigation. In view of the increasing importance of sunflower (Helianthus annuus L.) in this region as a potential source of renewable energy, this study was conducted to evaluate sunflower crops irrigated with different water salinity levels (ECw) and fertilized with nitrogen. The experiment was conducted in a greenhouse of the Federal University of Campina Grande (UFCG), from July to […]

Nitrogen usually determines the productive potential of forage crops, although it is highly unstable in the environment. Studies on recovery rates and use efficiency are important for more reliable fertilizer recommendations to reduce costs and avoid environmental pollution. The purpose of this study was to evaluate N use efficiency and recovery rate of Alexandergrass pasture (Brachiaria – Syn. Urochloa plantaginea) as well as N-NO3– and N-NH4+ soil concentrations using different levels of N fertilization under two grazing intensities. The experiment […]

A change in the type of land use, if not properly planned and conducted, may result in soils with diminished production capacity and increased erosion susceptibility, which will reduce crop yields and hamper soil and water conservation. This study had the purpose of investigating the soil erosion caused by rainfall in an originally native pasture area, in the second and third year of cultivation of two annual row crops (respectively, cowpea – Vigna unguiculata – and shorgum – Shorgum bicolor), […]

Map units directly related to properties of soil-landscape are generated by local soil classes. Therefore to take into consideration the knowledge of farmers is essential to automate the procedure. The aim of this study was to map local soil classes by computer-assisted cartography (CAC), using several combinations of topographic properties produced by GIS (digital elevation model, aspect, slope, and profile curvature). A decision tree was used to find the number of topographic properties required for digital cartography of the local […]

The negative impacts of the increasing volume of wastewater and of its discharge into the environment have become a worldwide concern. This study assessed the potential impacts of using treated effluent from pig raising for cotton irrigation, to evaluate their effects on soil chemical properties, and compare the results with those under conventional management. The experiment was conducted in an experimental area of the Company for the Development of the San Francisco and Parnaíba valleys “Perímetro Irrigado Formoso”, in Bom […]

The Brazilian program of environmental services, called “Water Supplier”, is based on financial incentives relative to the erosion reduction by the implementation of voluntary soil conservation projects by farmers. However, this program has no pre-established restrictions of eligibility of application areas or conservation proposals. With a view to contribute to the methodological development of this program, a new approach was proposed, by analysis of two main changes: introduction of eligibility criteria, and the use of land suitability for recommendation of […]

Some rocks used in fertilizer production contain low water-soluble impurities, such as iron and aluminum phosphates. The industrialization processes of these rocks may generate simple superphosphate with an insufficient solubility degree to meet the requirements established by Brazilian fertilizer law. If applied to waterlogged soils, reduction reactions can increase the solubility of such fertilizers. The objective of this study was to evaluate phosphorus release from these fertilizers from flooded lowland soils of Rio Grande do Sul State. Six lowland samples […]

This study evaluated different environmental variables in the digital soil mapping of an area in the northern region of Minas Gerais State, using artificial neural networks. The environmental variables terrain attributes (slope and compound topographic index), the quickbird bands 1, 2 and 3, and lithology were evaluated. The importance of each of the variables in the classification was tested. The “Java Neural Network Simulator” was used with the backpropagation learning algorithm. For each dataset a neural network was created to […]

Archeological sites are frequent in the Brazilian Amazon. The physical, chemical and morphological properties, due to anthropic influence, are quite different from surrounding soils, mainly in the uplands. Although several studies have been carried out to understand the magnitude of these modifications and their influence on the genesis of such soils, aspects such as the mineralogical properties need to be better described. This study aimed at evaluating the chemical and mineralogical properties of anthropic horizons (Au) of soils of upland […]