Volume 33, Number 1, 2009

The effect of urea-N rates (40, 80 and 120 kg ha-1 N) and the distance (0, 27 and 35 cm) from sink (leaf) to source (urea applied to soil) on leaf absorption of ammonia by the pasture species Panicum maximum cv. Tanzania was evaluated. A randomized design was used in a split-plot arrangement with four replicates. The distance had no effect on leaf ammonia absorption (p < 0.05), but the absorption decreased exponentially (p < 0.05) with increasing N-rates or ammonia volatilization rates. Leaf ammonia absorption varied […]

In view of the high cost of fertilizers and the importance of mineral nutrition on the technology level used by rice producers for yields in southern Brazil, the use of evaluation techniques of the nutritional status, such as foliar diagnosis has become essential. Among the methods for nutritional plant diagnosis, the Diagnosis and Recommendation Integrated System (DRIS) stands out, which is based on the concept of nutrient balance. The objective of this study was to establish a DRIS reference norm […]

The soil types Neossolos Litólicos (Leptosols) and Neossolos Regolíticos (Regosols) have been poorly studied in Brazil, due to their relatively low potential for agricultural use. Consequently the morphological description of Neossolos in the field is also hampered, particularly in terms of contacts between soil, saprolite and rock, and their classification in the Brazilian Soil Classification System. The purpose of this study was: to define morphologically the contact between soil, saprolite and rock in Neossolos; generate data of the saprolite layer […]

Soil physical characteristics were evaluated of a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo, State of Rio Grande do Sul, Brazil, after ten years (1993 to 2003) under mixed production systems. The effects of production systems integrating grain production with winter annual and perennial forages under no-tillage were assessed. Five mixed cropping systems were evaluated: I) wheat/soybean, white oat/soybean, and common vetch/corn; II) wheat/soybean, white oat/soybean, and annual forages (black oat + common vetch)/corn; III) perennial cool […]

The impact of charcoal production on soil hydraulic properties, runoff response and erosion susceptibility were studied in both field and simulation experiments. Core and composite samples, from 12 randomly selected sites within the catchment of Kotokosu were taken from the 0-10 cm layer of a charcoal site soil (CSS) and adjacent field soils (AFS). These samples were used to determine saturated hydraulic conductivity (Ksat), bulk density, total porosity, soil texture and color. Infiltration, surface albedo and soil surface temperature were also […]

As knowledge on no-till system expands, it has become quite clear that separate chemical indicators cannot provide a detailed soil characterization. The objective of this study was to evaluate the effects of tillage systems and soil use in the physical, chemical and biological properties of a clayey dystrophic Red Latosol – Oxisol and a sandy Neosol – Entisol. The treatments for the Oxisol consisted of: native savanna, pasture, conventional tillage, no-tillage with turnip and with forage sorghum as cover crop. […]

With the expansion of the sugar/alcohol sector, the native vegetation was removed from soils with few limitations as well as with great risks for intensive cultivation and the areas incorporated in the production process. Therefore, the adoption of management systems that maintain the soil structure may be a key for the maintenance of the quality and sustainability of sugarcane production systems. The objective of this study was therefore to evaluate the use potential for sugarcane and structural quality of a […]

Knowledge on the surface runoff in watersheds is very important for a good conservation of natural resources. However, surface runoff is a complex and dynamic process, especially in the context of spatial variability. An application of the Geographical Information System (GIS) tools in small grid cells is therefore adequate. This way, it is possible to consider the spatial behavior of variables associated to the origin of surface runoff. This study aimed to program the Hydrological Models SCS-CN (SCS-Curve Number) and […]

Soil management can have effects on nutrient availability and fruit yield. The objective of this study was to evaluate the effect of phytomass management forms of different cover crop species on soil chemical properties related to organic matter, nutrient availability, and on grapevine yields. The experiment was carried out in Embrapa Uva e Vinho, in Bento Gonçalves, RS, in Southern Brazil, on a Haplic Cambissol, in a vineyard established in 1989, using White and Rose Niagara grape in a horizontal […]

Campos Gerais in the State of Paraná (Brazil) is an important region of milk production and consequently of cattle slurry. The purposes of this study were: (a) to evaluate losses of water, soil, total P, soluble P and particulate P under simulated rainfall performed immediately after the application of 0, 30, 60 and 90 m3 ha-1 cattle slurry on a Red-Yellow Latossol (Ferralsol) under no-tillage system, and (b) to discuss the possible impacts on water quality. Slurry application increased the surface runoff […]