The constant use of fertilizers that does not contain sulfur, in addition to low organic matter content of some soils, may result in sulfur limitation to crops. Due to the high mobility of the sulfate ion in many soils, it is important to know the residual effect of the phosphogypsum when added to the soil as S source, in order to estimate its application frequency. Experiments were performed under field conditions, in two years, in order to evaluate the effect […]

The model SWAT (Soil and Water Assessment Tool) was used to simulate alternative scenarios of land use in Ribeirão dos Marins watershed, in Piracicaba, State of São Paulo, Brazil, for the biennial period 1999/2000. Two scenarios were simulated. The first one (scenario 1) was based on the current land use except for the introduction of a continuous riparian buffer of 30 m along the drainage network and of 50 m around the springs, in accordance to Brazil’s environmental legislation. In […]

In pastures, the evaluation of fertilization efficiency of urea-N is important since it is applied on a massive scale. Several studies report an enhancement of the fertilizer’s efficiency by associated applications of urea with potassium chloride (KCl) and ordinary superphosphate (OSP). In the recovery of degraded pastures or in intensive exploration systems, high quantities of KCl and OSP used as corrective fertilization are applied at the november, beginning of the rain season. Split applications of KCl and OSP could easily […]

In order to achieve more sound fertilizer recommendations, knowledge about nutritional requirements of rice in different growing systems is fundamental. The objective of this paper was to evaluate the effects of water levels on nutrition and nutrient exportation by upland rice (cultivar IAC 201) under two levels of mineral fertilizer. Experiments were conducted in the growing seasons of 1994/95 and 1995/96 on a Typic Haplustox, in Selvíria, State of Mato Grosso do Sul, Brazil. The experimental design was of randomized […]

Dynamics of decomposition and nitrogen (N) release of cover crop residues in mixed and single cultures was evaluated in a field experiment. The following materials were used: (a) black oat (Avena strigosa Schieb); (b) common vetch (Vicia sativa L.); (c) oilseed radish (Raphanus sativus L. var. oleiferus Metzg.); (d) 32 % black oat + 68 % common vetch, and (e) 51 % black oat + 49 % common vetch. To monitor the residue decomposition, air-dried plant material was inserted in 0.5 mm mesh nylon-bags (0.2 […]

This greenhouse experiment was carried out to evaluate the effects of arbuscular mycorrhizal fungi (AMF) and Rhizobium on dry matter production, N uptake and efficiency of use in Eucalyptus grandis and Sesbania virgata plants grown in intercropping systems. The transfer of N from Sesbania virgata to Eucalyptus was also evaluated, using the isotope 15N. The treatments were: with or without inoculation of both plant species with AMF and with or without inoculation of S. virgata with Rhizobium. Plastic pots divided […]

Eucalyptus and acacia species are widely used in agrosilviculture and reforestry practices. In order to evaluate the reconstitution of organic soil layers – i.e. the humic horizons -and establish relationships to the soil properties, the holorganic and hemiorganic horizons were sampled under Acacia mangium and Eucalyptus grandis plantations. These plantations lie in the tertiary tableland region in the North of Espírito Santo State, Brazil, and are part of the Natural reservation Area of the Vale do Rio Doce Company. Samples […]

The efficiency of three new phosphate fertilizers (test sources, TS) was assessed and compared to traditional P fertilizers in terms of nutrition and yield of soybeans, on three different soils: a Quartzarenic Neosol, a loamy dystrophic Red-Yellow Latosol, and a clayey dystrophic Red-Yellow Latosol. The greenhouse experiments, in a factorial layout of (2 x 4) + 8, compared two TS (TS1 and TS2) in four doses, with eight additional treatments for each soil [triple superphosphate with calcitic lime, triple superphosphate […]

From 1920 on, Ferralsols of the Planalto Médio region in the State of Rio Grande do Sul, Brazil, originally under forest vegetation, were converted into agricultural land, while the same soils under grassland were converted in the 1960-ies. Thereafter, chemical soil properties were affected by intense cropping, mainly of soybean and corn. To evaluate how the time of agricultural land use affected two Ferralsols in the Fortaleza dos Valos county, State of Rio Grande do Sul, pedon samples of a […]

Soil management affects the soil physical quality, but the magnitude of the changes is dependent of use time and regional edaphoclimatic conditions. The objective of this study was to evaluate the long-term (21 yr) effect of conventional tillage (CT) and no-tillage (NT) systems on some physical properties in the 0.2 m top layer of an Oxisol from Paraná, southern Brazil. In comparison with an adjacent forest soil used as reference, the use of CT system increased the soil bulk density, penetrometer resistance […]