The use of organic residues in the crop fertilizations demand information about the dynamics of decomposition and release of nutrients contained therein. This study aimed to evaluate the decomposition and release of N, P and K from organic residues cattle manure and poultry litter isolates or mixed, using the method of decomposition bags (litterbag) in Alfissol of Coast Tableland in Paraiba State. The experiment was conducted in randomized block with treatments arranged in a factorial 3 × 2 × 5 […]

The use of urban waste compost as nutrient source in agriculture has been a subject of investigation in Brazil and elsewhere, although the effects on soil physical and chemical properties and processes are still poorly known. The aim of this study was to evaluate the effect of application of urban waste compost and mineral fertilizer on soil aggregate stability and organic carbon and total nitrogen content of a Rhodic Hapludox under no-tillage in the northwestern region of Rio Grande do […]

In areas of intensive pig production, pig slurry is used as an important nitrogen (N) source of crops, but is also a major cause of soil, air and water pollution. Strategies are required to reduce N losses from this organic material to the environment and to improve the agronomic efficiency as plant N source. The purpose of this study was to evaluate the effect of the use of a nitrification inhibitor (NI) and the split application of pig slurry (PS) […]

Campos Gerais in the State of Paraná (Brazil) is an important region of milk production and consequently of cattle slurry. The purposes of this study were: (a) to evaluate losses of water, soil, total P, soluble P and particulate P under simulated rainfall performed immediately after the application of 0, 30, 60 and 90 m3 ha-1 cattle slurry on a Red-Yellow Latossol (Ferralsol) under no-tillage system, and (b) to discuss the possible impacts on water quality. Slurry application increased the surface runoff […]

Deactivation of saltworks in Cabo Frio, Rio de Janeiro, has been creating great amounts of organic residues originated from marine algae accumulation. Studies were carried out at the Soil Department of UFRRJ in 1996 to evaluate the potential for using such residues as organic fertilizers. Samples of the residue presented high contents of Ca, Mg, K, Na, S, and elevated values of bulk and real densities, water retention, pH and electrical conductivity; 89% of Na content was found in soluble […]

A gibbsitic Red-Yellow Oxisol with electropositive carater was used to study the effect of organic matter on electrochemical properties and dispersion mechanisms. Two organic sources were used, one characterized by non-humified compounds (cattle manure) and another by humified compounds (peat humic acids). The soil was incubated with 0; 7,5; 15,0; 22,5 and 30,0 g kg-1 of organic manure. Water dispersible clay, electrical conductivity, water and KCl pH, and the zero point of saline effect (ZPSE) and superficial electric potential (Ψo) […]