Volume 38, Number 3, 2014

The increasing level of land degradation has led to the adoption of agricultural management practices that seek to combine agricultural production and soil conservation. Among these, the practice of Crop-Livestock Integration (CLI) has intensified in West-Central Brazil. In order to assess the long-term effect of the CLI system and seasonality on the community of soil macrofauna and oxidizable fractions of total organic C in croplands and the Cerradão (Brazilian tropical savanna), a study was developed at the Cabeceira Farm in […]

The application of organic residues to the soil can increase soluble organic carbon (SOC) and affect the pH and electrolytic conductivity (EC) of the soil. However, the magnitude of these changes depends on the type of residue and the applied dose. This study aimed to evaluate the effect of increasing C rates contained in organic residue on the pH, EC, water-extractable total carbon (WETC), water-extractable organic carbon (WEOC), and water-extractable inorganic carbon (WEIC) in soil treated with manure (chicken, swine, […]

Layered double hydroxides (LDHs) are potential anionic intercalators. To obtain nitrate slow-release fertilizers, LDHs with the general formula [M2+1-xM3+x(OH)2]x-(NO3)x.yH2O (where M2+ = Mg2+ and M3+ = Al3+ and/or Fe3+) were synthesized by the method of co-precipitation at constant alkaline pH. The X-ray diffraction (XRD) measurements showed that crystallinity increases with the pH value and with the M2+/M3+ molar ratio. The FTIR measurements showed characteristic bands of free nitrate in the interlayer, as well as minor carbonate ion contamination. The compositions […]

Nutrient availability during the year can affect the performance of macadamia (Macadamia integrifolia). However, there is no information about this crop responses to split application of fertilizer under Brazilian conditions. The aim of this study was to evaluate the influence of splitting the application of chemical fertilizers on the nutrition, yield, and quality of nuts of the macadamia nut tree. The experiment was conducted over three growing seasons on an Oxisol in Jaboticabal, State of São Paulo, Brazil. A randomized […]

Nitrogen supplementation has been an important means for increasing yield in tropical gramineous forage plants in Brazil because, in most growing areas, the levels of this nutrient in the soil do not adequately meet crop needs. We assessed the effect of different sources and application rates of N on the chemical properties of an Oxisol (Latossolo Amarelo) and the production of Panicum maximum cv. Mombaça. The experiment was carried out at the Instituto Federal do Espírito Santo (State of Espirito […]

Measurement of chlorophyll fluorescence can be a useful tool for detecting changes in the photosynthetic apparatus of plants. With the understanding that early detection of zinc (Zn) contamination is fundamental in environmental monitoring, the aim of this study was to assess Zn stress in castor bean (Ricinus communis) plants using X-ray chlorophyll fluorescence. The changes brought about by Zn in photosynthetic pigments and in the mineral composition of plants were also studied. Castor bean plants were grown for 28 days […]

The common bean crop is of great importance for the State of Goiás, Brazil. However, information on its nutritional requirements is lacking for irrigated conditions. The aim of this study was to establish standard levels of leaf nutrients and assess the nutritional status of irrigated common bean in the Vale do Rio dos Bois region of the State of Goiás through the methods of sufficiency range (SR), compositional nutrient diagnosis (CND), and diagnosis and recommendation integrated system (DRIS), as well […]

Most natural pastures in the Campos biome in Southern Brazil grow in soils with low phosphorus (P) availability, but with high contents of total and organic P. The present study aimed to evaluate the changes in forms of soil P resulting from the application of phosphate sources over a growth cycle of natural pastures. In three experiments under natural pasture, P was applied in the form of Gafsa rock phosphate, triple superphosphate, and a control treatment in a randomized block […]

The species of the Eucalyptus genus are the most cultivated in the world and have become a solution for reducing the pressure on native forests. The aim of this study was to evaluate the dry biomass and its distribution in the different compartments of the trees (leaves, branches, bark, wood and roots), and assess their macronutrient content and nutrient balance in the soil-plant system in a Eucalyptus urophylla x E. grandis plantation at 60 months of age on the Água […]

The phosphorus supply to crops in tropical soils is deficient due to its somewhat insoluble nature in soil, and addition of P fertilizers has been necessary to achieve high yields. The objective of this study was to examine the mechanisms through which a cover crop (Congo grass – Brachiaria ruziziensis) in rotation with soybean can enhance soil and fertilizer P availability using long-term field trials and laboratory chemical fractionation approaches. The experimental field had been cropped to soybean in rotation […]