The productivity of cupuassu orchards in the Amazon region has been gradually declining, probably due to the reduction in soil fertility, calling for fertilization. In the absence of technical recommendations to calculate the nutrient demand of an orchard, the use of the Integrated Diagnosis and Recommendation (DRIS) may represent an alternative to fill this gap. The purpose of this study was to evaluate the diagnoses based on different formulas and criteria of interpretation of DRIS indices of cupuassu orchards. The […]

Silicon is considered an important chemical element for rice, because it can improve tolerance to biotic and abiotic stress. However, in many situations no positive effect of silicon was observed, probably due to genetic factors. The objective of this research was to monitor Si uptake kinetics and identify responses of rice cultivars in terms of Si uptake capacity and use. The experiment was carried out in a greenhouse of the São Paulo State University (UNESP), Brazil. The experiment was arranged […]

Agricultural activity, by the application of different soil management practices, can cause impacts on soil production capacity that need to be assessed. In this study, different microbiological parameters were evaluated, to assess the relation of soil quality with different tillage practices and crop systems, in comparison to a natural reference soil. The activities of β-glucosidase, urease, acid phosphatase and arylsulphatase were evaluated, as well as soil microbial respiratory activity and microbial biomass. Conventional tillage (CT) and no-tillage (NT) were evaluated […]

Soil penetration resistance is an important property that affects root growth and elongation and water movement in the soil. Since no-till systems tend to increase organic matter in the soil, the purpose of this study was to evaluate the efficiency with which soil penetration resistance is estimated using a proposed model based on moisture content, density and organic matter content in an Oxisol containing 665, 221 and 114 g kg-1 of clay, silt and sand respectively under annual no-till cropping, […]

Soil management strategies to improve and maintain soil physical quality (SPhQ) are essential for the sustainability of intensive agricultural systems. The least limiting water range (LLWR) is an indicator of SPhQ defined by the range of least restrictive soil water content to plants, i.e., a soil water content within the LLWR indicates an appropriate SPhQ for plants. In this context, soil mulching with crop residues can contribute to the SPhQ by increasing the frequency at which soil water availability is […]

Gully erosion occurs by the combined action of splash, sheetwash and rill-wash (interrill and rill erosion). These erosion processes have a great capacity for both sediment production and sediment transport. The objectives of this experiment were to evaluate hydrological and sediment transport in a degraded area, severely dissected by gullies; to assess the hydraulic flow characteristics and their aggregate transport capacity; and to measure the initial splash erosion rate. In the study area in Guarapuava, State of Paraná, Brazil (lat […]

The relationships between nutrient contents and indices of the Diagnosis and Recommendation Integrated System (DRIS) are a useful basis to determine appropriate ranges for the interpretation of leaf nutrient contents. The purpose of this study was to establish Beaufils ranges from statistical models of the relationship between foliar concentrations and DRIS indices, generated by two systems of DRIS norms – the F value and natural logarithm transformation – and assess the nutritional status of cotton plants, based on these Beaufils […]

The fractionation of inorganic phosphorus (Pi) is important to evaluate in which forms phosphorus is sorbed to soil, because the efficiency of an extractant of available P in soils depends on its capacity to extract each fraction of soil Pi. This study evaluated the contents of Pi fractions in representative soils of the State of Paraiba and their relationship with the chemical and physical characteristics of these soils, as well as the correlation between the Pi fractions and P extracted […]

In spite of the high amount of N accumulated in high-yielding, short-rotation eucalyptus plantations, no significant or consistent increases in trunk volume have been observed in response to N fertilization. This experiment evaluated the effect of N fertilization on the growth and chemical composition of eucalyptus as well as its role in soil organic matter (SOM) mineralization. The field experiment was carried out in a randomized block design with three replications, in Itamarandiba- MG. Two N sources (ammonium sulphate and […]

Sugarcane, which involves the use of agricultural machinery in all crop stages, from soil preparation to harvest, is currently one of the most relevant crops for agribusiness in Brazil. The purpose of this study was to investigate soil physical properties and root growth in a eutroferric red Oxisol (Latossolo Vermelho eutroférrico) after different periods under sugarcane. The study was carried out in a cane plantation in Rolândia, Paraná State, where treatments consisted of a number of cuts (1, 3, 8, […]