Soil Science deals with the understanding and modelling of the phenomena occurring in soils, mainly those related to the non-saturated zone. Since understanding most of those phenomena requires determination of parameters in scales allowing the incorporation of pore and aggregate variability to the models, a microscopic scale X-ray tomograph was built at Embrapa Agriculture Instrumentation. The aim was to generate non-destructive images of soil samples, within at least 100 ∝m spatial resolution. It was possible to design and construct a […]

Attributes of soil, climate and crop management were characterized in ten growing coffee plantations in the western region of São Paulo State. The purpose of this work was to identify the main limiting productivity factors and develop a simple multivariate model to explain observed yield in the period between 1984 and 1989. Over two thousand traits were initially analyzed by simple correlation to the final yield, and the significant ones, with at least 5% level according to the Student test […]

The objective of this work was to investigate the effect of increasing closes of Irati lime on the contents of Cu, Fe, Mn and Zn both in soil and the corn plant. Irati lime is a by product obtained by Petrobras Six during the oil shale mining process, presenting high levels of micronutrients. The experiment was conducted in a greenhouse using pots filled with soil from a “Cambisol Tb” A horizon, of a sandy texture. The treatments were arranged in […]

Based on the seven year-productivities (1989 to 1995) of 36 cacao-producing areas, on a farm in southern of Bahia, Brazil, the average of the three most and least productive years was obtained corresponding, respectively, to the highest and lowest rain availability. By path analysis, these productivities were related to both the soil morphological-physical characteristics (A-horizon depth; color, soil and particle densities of A and B horizons; texture of soil layers at 0-20 and 30-50 cm depth and the presence of […]

Phosphorus dynamics and availability to plants in waterlogged soils involve complex processes which differ substantially from those verified in well drained soils. In order to study P availability to rice growing in waterlogged soils, a greenhouse pot trial was performed with nine lowland rice soil samples from Minas Gerais, Brazil. Six phosphorus rates combined with two liming rates were tested. The plants were grown for 60 days and the above ground dry weight and P concentration were determined after harvesting. […]

Planting spacings and sowing dates may influence nutrient absorption. Therefore, a field experiment was carried out from 1991 to 1992, at the experimental station of Embrapa/Soil Research National Center, located in Senador Canedo, Goiás, Brazil, to determine the N, P and K uptake levels in the aerial part of sunhemp (Crotalaria juncea), Crotalaria ochroleuca, black velvet bean (Mucuna aterrima) and pigeonpea cv. Kaki (Cajanus cajan), under three sowing times (beginning, middle and end of the growing season) and two spacings […]

The agricultural use of soil changes its physical, chemical and biological characteristics. In many instances, these alterations can result in degradation of soil quality, due to destruction of the natural soil cover and excessive use of machines. The objective of this study was to characterize the alterations of some physical and chemical properties of a dystrophic Dark Red Latosol under cerrado vegetation, under different land uses. The soil samples were taken from five different agro-ecosystems: native pasture; improved brachiaria pasture; […]

Phosphorus dynamics in waterlogged soils and sediments is environmentally important and seems closely related to redox reactions of iron compounds. In order to verify the effects of liming and phosphorus fertilization on soil Fe and P contents, nine lowland soil samples from Minas Gerais, Brazil, were treated with two lime and six phosphorus rates. After an aerobic incubation period, the soil Fe and P concentrations were determined by ammonium-acetate, Mehlich-1 and ammonium-oxalate extractants. The soils were then waterlogged and the […]

Many extracting procedures for the plant-available zinc have been developed. Total soil Zn fractionation has been used as an attempt to understand the reactions of this nutrient in soils and the behaviour of the extracting procedures. This work evaluated the influence of soil characteristics on the concentration of Zn extracted by different procedures and on soil Zn fractions. Samples were collected from the 0-20 cm surface layer of twelve soils, representing the great soil groups of Dark-Red Latosol (LE), Red-Yellow […]

The objectives of this study were to determine the influence of different soil tillage methods on the loss of heavy metals by erosion, and to evaluate the level of contamination in sediments and water from the main stream in Caetés watershed, Paty do Alferes County, Rio de Janeiro. The experiment was conducted from December 1996 to March 1997, and cucumber (Cucumis sativus L.) was the cultivated crop. Four Wichmeier plots were installed, with an area of 22 x 4 m. […]