Nutrient balance in tropical forest allows an evaluation of eventual differences due to management practices and conclusions on forest sustainability. The aim of this study was to evaluate the nutrient concentration in native species and quantify biomass production and C and nutrient balance in tropical montane Atlantic Forest fragments (Dense Montane Ombrophile Forest) in the North of Rio de Janeiro State, from May 1999 to April 2001. Two sites were selected in the State Park of Desengano, at 900 and […]

Wheat is the main winter crop in Rio Grande do Sul State, Brazil, and the calculation of soil water balance is an important element in simulation models for crop growth, development and yield. The objective of this study was to improve the water balance estimation in soil under wheat by two modified models. The soil water content was measured by the gravimetric method during the growing season of two wheat cultivars sown on three dates in Santa Maria, RS, Brazil. […]

The nutritional demand of pineapple plants is higher than for other crops and IT depends on cultivar, fruit weight, production destination and planting density and cultivation system. However, the variation in these factors is not always taken into account in fertilization tables. The purpose of this study was to propose a fertilizer and lime recommendation system for pineapple designated FERTCALC-Abacaxi, based on systematization and modeling of literature data and the current knowledge concerning fertilization and mineral nutrition of the crop. […]

Soil water properties are related to crop growth and environmental aspects and are influenced by the degree of soil compaction. The objective of this study was to determine the water infiltration and hydraulic conductivity of saturated soil under field conditions in terms of the compaction degree of two Oxisols under a no-tillage (NT). Two commercial fields were studied in the state of Rio Grande do Sul, Brazil: one a Haplortox after 14 years under NT; the other a Hapludox after […]

High wheat yields require good N fertilization management. The objective of this study was to evaluate the effects of different N applications at sowing using Entec (N source with nitrification inhibitor) and urea (traditional N source) at covering, on four wheat cultivars. The experiment was conducted in a randomized block design in a factorial scheme, with four replications, at the Experimental Station of the Faculdade de Engenharia de Ilha Solteira – UNESP, on a dystrophic, epi-eutrophic alic Red Latosol with […]

In the Earth’s carbon cycle, C stocks in the soil are higher than in vegetation and atmosphere. Maintaining and conserving organic C concentrations in the soil by specific management practices can improve soil fertility and productivity. The aim of this study was to evaluate the impact of agricultural management techniques and influence of water regime (flooded or drained) on the structure of humic substances by excitation/emission matrix fluorescence. Six samples of a Planosol (Planossolo by the Brazilian System of Soil […]

The sustainability of irrigated rice (Oryza sativa L.) in lowland soils is based on the use of crop rotation and succession, which are essential for the control of red and black rice. The effects on the soil properties deserve studies, particularly on soil compaction. The objective of this study was to identify compacted layers in an Albaqualf under different cultivation and tillage systems, by evaluating the soil bulk density (Ds) with Gamma Ray Computed Tomography (TC). The analysis was carried […]

The management system normally affects soil nutrient availability, as a consequence of tillage practices, crop rotation and crop residues remaining in the cultivated area. The objective of this study was to evaluate the alterations in cation availability in two Oxisols in the Brazilian Cerrado under conventional and no-tillage systems for more than 10 years. The experiments were conducted in Costa Rica, state of Mato Grosso do Sul, and in Luziânia, Goiás. Both soils were Oxisols, but one being a Red Latosol […]

The use of animal manure in agricultural systems can cause water contamination and/or pollution by nutrients, especially by consecutive applications to the same area. In view thereof, the purpose of this study was to evaluate the effect of manure and fertilizer application on NH4+, NO3–, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses […]

The determination of As by hydride generation atomic absorption spectroscopy (HG-AAS) is a simple, sensitive, precise and low-cost method. However, this technique requires the pre-reduction of the existing As(V) species, which is obtained by the use of reducing agents such as KI. In extracts containing oxidizing agents, the pre-reduction of As is impaired, as it occurs in extracts obtained by the BCR (French acronym for Community Bureau of Reference) method for the sequential extraction of As in sediments. The objective […]