Volume 25, Number 3, 2001

This work was conducted under greenhouse conditions to evaluate how doses and methods of manganese (Mn) application may affect vegetative characteristics as well as the production of upland rice. The treatments consisted of five manganese doses applied either via soil (0, 4, 8, and 16 mg dm-3) or leaf (3 4 g L-1 applications), associated with two rice cultivars (Canastra and Confiança). The experiment was randomly designed, with four replications, in a 2 x 5 factorial scheme. Each plot consisted […]

Manures used as phosphorus sources may have different efficiencies from those of commercial soluble fertilizers. These efficiencies may vary according to the manure origin and to the proportions of its total P in different chemical fractions. A greenhouse experiment was conducted in order to estimate the efficiencies of dairy cattle and chicken manures as phosphorus source, in comparison to triple superphosphate (TSP), as well as to relate these efficiencies to their P fractions. The treatments were: control, without fertilizer or […]

Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol located in Passo Fundo, Rio Grande do Sul, Brazil, after five years of combined production systems (1993 to 1997). The effects of integrated grain production systems and with winter annual and perennial pastures under no-tillage were assessed. Four production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures […]

The consequences of micronutrient deficiency or toxicity for the agricultural productivity in the state of Rio de Janeiro are not adequately known. For this reason, in 1997, the levels of copper, zinc, iron, and manganese were quantified in 103 samples from surface horizons of representative soils of the state. The extractant solutions used were Mehlich-1, DTPA-TEA, and HCl 0.1 mol L-1. In general, the HCl 0.1 mol L-1 solution extracted the highest amounts of the studied micronutrients. Mehlich-1 extracted the […]

The Serra do Brigadeiro State Park is covered by tropical Atlantic rain forest, as part of the Mantiqueira crystaline range. In the upper areas (above 1.600 m), a type of vegetation with singular floristic composition is found, with high endemism and a number of endangered species, here called “Campos de Altitude”. A Lithosol, a Spodosol (Podzol) and a Cambisol, all associated with “Campos de Altitude”, and a Latosol under rain forest, were sampled. These soils showed high Al saturation, low […]

The GIS-IDRISI was used to check land use adequacy from 1997 to 1998, in the initial part of the Rio Pardo basin, in Botucatu/Pardinho (SP), to obtain a suitable land use planning of the area. The classes and subclasses of land capability were determined according to the Land Capability Classification System. The lands of the studied area were classified as: class VIe, lands with erosion susceptibility (90.49%); class Va, flat lands, with no erosion risk, but limited by excess of […]

Using simulated rainfall on a 0.12 m m-1-slope typic Hapludalf (Red Yellow Podzolic Soil), sandy-loam soil, erosion losses by water were evaluated during corn (Zea mays L.) that had followed oats (Avena strigosa Schieb) and bare-fallow in the winter. Field work was conducted at the Silviculture Experimental Station of the Secretary of Agriculture of Rio Grande do Sul, Brazil, from 1994 to 1995. Conventional and no-tillage performed with animal and tractor traction were the main treatments studied. Rainfall was applied […]

The estimate of maximum rainfall intensity is of great concern in agricultural projects such as the use of terraces for erosion control, dams, and soil water drainage. Rainfalls can be characterized by their intensity (mm h-1), duration time (min), and return period (years). One of the analyzed models has been used for estimating the maximum rainfall intensity to be applied in dimensioning such agricultural structures, for a given return period and storm duration. The time of concentration in small watersheds, […]

In a natural landscape, the soils present a wide variation on morphological, physical, chemical and mineralogical properties due to several soil formation factors. In a cultivated landscape others sources of variation may be present, such as anthropogenical processes. The knowledgement of these variations is important to soil survey, development of sampling designs and soil management practices. This work aimed to study the spatial variability of some physicals attributes of a Dystrophic Red Latosol cropped in no tillage system. It was […]

Legumes cover-crops represent a good alternative to supply N as well as to improve yield of commercial crops. The acceptance of this technique by growers and extension agents, however, depends on its economical advantage in relation to traditional systems. In this study, the effect of four summer legumes cover-crops (Canavalia ensiformis, Cajanus cajan, Stizolobium niveum and Glycine sp), was evaluated in association with three N rates (0, 60 and 120 kg ha-1), on the net income of corn. Two medium-term […]