Samples of 30 soils were taken with the objective of characterizing the Capacity Factor of Phosphorus (CFP) and its relation with several properties of soils of Entre Ríos, Argentina. Isotherms of adsorption and a quick test of P adsorption were estimated. Langmuir and Freundlich equations described the adsorption phenomenon satisfactorily. The maximum adsorption capacity varied between 46 and 716 mg kg-1 of P in the soil, considering that the soils analyzed have from medium to low CFP. The adsorption capacity […]

Soil spatial variability of phosphorus, potassium, and organic matter was studied in different soils and management systems, in two counties: a) Eldorado do Sul, State of Rio Grande do Sul, Brazil, on a Dark Red Podzolic-Kandiudult (conventional tillage, no-tillage, minimum tillage, and pasture), using a grid sampling of 1 x 1 m and at depths of 0-0.05 and 0.05-0.20 m; b) Passo Fundo, State of Rio Grande do Sul, Brazil, on a Dusky Red Latosol – Hapludox (conventional tillage and […]

A greenhouse experiment was carried out during the period October, 1991 to December, 1992, to evaluate the mass flow and diffusion contributions on sulphur transport to corn roots in soil surface samples (0-20 cm) of three acid soils collected in Viçosa, Paracatu and Lassance, Minas Gerais State, Brazil. Originally, the soil samples presented 5.0, 1.2 and 1.4 mg dm-3 of available S, respectively, obtained by extraction with a Ca(H2PO4)2 solution containing 500 mg L-1 of P in HOAc 2 mol […]

A field experiment was carried out to study the effects of potassium fertilization and time of harvesting on canola seed yield. The soil was a Red-Yellow Latosol (Hapludox), and the experimental design was a subplot replicated four times in completely randomized blocks. Potassium levels (0 and 40 kg ha-1 of K) were applied in the plots, and the subplots consisted of 7 weekly harvests, starting 112 days after planting. Yield and yield components were evaluated at each harvest. Although no […]

The knowledge of intense rainfall magnitude is very important for the elaboration of hydraulic projects, management of hydric resources in engineering and structure dimensionality for the water erosion control on soil conservation. However, information about the rainfall intensity can only be obtained directly from pluviograms, which quite often are not available at the study site, where the presence of pluviometer data (rainfall of “one day”) is more common. In this case, the disaggregation of daily rainfall into 24 hour periods […]

Agroforestry systems combine crop productivity with environmental sustainability while conserving fertilizer through nutrient cycling. Plant biomass production and nutrient inputs were measured in an alley cropping system and in native cerrado site at Botucatu, State of São Paulo, Brazil, and the influence of agroforestry practices on the soil chemical attributes were determined. Leucaena was planted in 1987, in hedgerows 6 m apart, following lime and P applications. Legume hedgerows were pruned annually, allowing for cereal intercropping of rye with oat […]

To get more efficient wheat varieties in phosphorus uptake and/or utilization it is important to look for the causes of the greater efficiency of particular varieties. One experiment in nutrient solution with four concentrations of phosphorus (1.6, 4.8, 12.9 and 32.3 µmol L-1) was conducted to compare efficient (Toropi and IAC 5) and inefficient cultivars (IAS 20 and CNT 8) in phosphorus uptake in relation to the amount of phosphorus taken up, phosphorus translocation and utilization, dry matter production and […]

Corn grain yield is very responsive do Zn in Brazilian soils. A greenhouse experiment was conducted in the Crop Science Department of the Botucatu College of Agricultural Sciences to compare sources of Zn and their application to corn. Three plants were grown up to 45 days in 10 L pots filled with a Dark Red Latosol (Acrortox, 22% clay). The soil was limed to 70% of base saturation. Zinc was applied to corn seeds (90 g ha-1), in the seed […]

The packing condition of the soil is important for providing direction for land management. In soils developed from recent sediments, the tendency to packing may be related to inherited characteristcs from sedimentation conditions. In a soil toposequence from sandy sediments of Barreiras geological group, in Caravelas city – Bahia, eight soil profiles were selected, five of them from a eucalypt plantation. The soils were allocated in five great groups: Fluvaquent (P1),Duraquod (P2, P8), Haplorthod (P3), Hapludult (P4, P5, P7) and […]

Soybean response to potassium fertilization was evaluated over a twelve-year period in a field experiment on a Haplohumox soil, in Campos Novos, State of Santa Catarina, Brazil. Treatments consisted of a combination of four levels of K2O applied in the first year (0, 80, 160 and 320 kg ha1), and three levels of K2O (0, 40 and 80 kg ha-1) applied annually from the fifth year. The critical level of K in the soil and in the leaves was determined […]