Fifty eight plots of 480 m2 (20 x 24 m) were established in stands of 5.5 year-old Eucalyptus grandis, growing in Rio Doce Valley – MG, Brazil, in order to study the relationship between growth and site characteristics. The topography of the area is hilly and the soil predominantly Oxisol, originated from granite-gnaiss parent material. A discriminant model with two linear functions was obtained and allowed to correctly classify 86.2% of the plots. The discriminant model obtained showed a holistic […]

The objective of this research was to evaluate the effects of potassium rates and water stress levels on the growth of maize (Zea mays, L.) plants. A pot (40 dm3) experiment was carried out using a “Terra Roxa Estruturada Latossólica”, an Alfisol intergrade to Oxisol, clayey loam soil, in Botucatu – São Paulo, Brazil, from December 1994 to February 1995. The experimental design was a randomized block with a (2 x 3 x 5) factorial distribution of the treatments. Two […]

The state of Rio de Janeiro, Brazil, is characterized by three main geomorphologic formations, the landform constituted by crystalline rocks, exposed or covered by their alteration products; coastal tablelands, formed by Barreiras Formation Tertiary sediments; and alluvial floodplain sediments of Quaternary age. Differences between parent material and topography and their influence on soil genesis have been the main subject of studies in Rio de Janeiro. The objective of this study was to analyze the behavior of extractable forms of iron, […]

To test the performance of a numeric model in prediction of water content (θ) and tension (|ψm|) in time and space, data were chosen from the literature on two porous materials with different hydraulic properties: a marine sand (quatzipsamment) of Tottori, Japan and a sandy phase Red-Yellow Latosol (Haplustox) of Piracicaba, SP. The results led to the following conclusions: (a) in both porous materials studied, the behaviour of the model was highly significant, with the profiles of humidity aligning satisfactorily […]

Soil in natural conditions are in steady state in the environment. However, inadequate management can cause degradation mainly in the organic matter fraction, impiring the sustainability of agricultural systems. This experiment was conducted for 6 consecutive years in a Hapludalf (Red Yellow Podzolic Soil), at the experimental area of Soil Science Department UFSM. The objective was to evaluate the effects of plant successions on the carbon dynamic. The plant successions used were common vetch (Vicia sativa)/corn (Zea mays), blue lupine […]

Two field experiments were conducted on a dystrophic Dark Red Latosol (Haplortox) to study the effects of lime, cobalt and molybdenum on chlorophyll contents in the leaves of peanut. Seed treatments (cobalt, molybdenum, cobalt + molybdenum and no treatment) were applied in two peanut cultivars (“Tatu” and “Tupã”) grown in four rates of lime (0, 4, 6 and 8 t ha-1), causing an increase in leaf chlorophyll contents either due to Mo or lime application. Chlorophyll contents in the leaves […]

Losses of nutrients and organic matter due to hydric erosion are highly affected by soil management. Inadequate management systems may cause pollution and eutrophication of surface waters, fertilization cost increase, and ecosystems degradation. Nutrient and organic matter losses due to erosion were evaluated during six years on a very clayey Dusky Red Latosol, with a 0.03 m m-1 slope at Dourados, Mato Grosso do Sul, Brazil under natural rainfall conditions, and different soil management systems. The treatments applied in the crop succession […]

Soil water infiltration rate may be the soil property which best reflects the general soil physical conditions, especially the structural quality. A field study was conducted at the Embrapa Trigo, Passo Fundo, Brasil in an Oxisol under long-term soil tillage systems, to evaluate the influence of these systems on soil water infiltration rate as a function of the soil cover and soil physical conditions caused by the different tillage systems. During a corn cropping period, a simulated rainfall with intensity of […]

The reaction of nitrogen compounds with ninhydrin can be used as an indicator of cytoplasmic materials released from microbial cells killed by fumigation. Total-N, ninhydrin-reactive-N (NR-N), ammonium-N (A-N), and α-amino-N in the microbial biomass of soils from the State of Rio Grande do Sul, Brazil, were determined, in 1996, in 0.5 mol L-1 K2SO4 extracts of fumigated and non-fumigated soils. Total-N varied from 20.3 to 104.4 mg kg-1 and the ninhydrin-reactive-N corresponded, in average, to 27% of this. The ninhydrin-reactive-N was made up of […]

Soil heterogeneity is known to cause variability of soil-water storage. Thus intensive sampling is required to characterize its spatial pattern. For irrigation management, it is necessary to measure the soil water content between irrigations. The objectives of this paper are to identify whether spatial patterns of soil water content in sprinkler irrigated area present temporal stability and whether this property presents spatial dependence. Temporal stability of spatial dependence structures and spatial correlation with clay content were studied. A 180 m long […]