Alexandre Swarowsky

Crescimento e qualidade de mudas de Timbó e Dedaleiro cultivadas em solo contaminado por cobre

The mining and viticulture activities in the State of Rio Grande do Sul, Brazil have contributed to soil contamination by copper. The aim of this study was to evaluate the effect of copper doses on growth and quality of Ateleia glazioviana and Lafoensia pacari seedlings. The experimental design was completely randomized in a factorial scheme (2 x 4) with five replications. The experiment involved two forest species and three copper doses (64, 128 and 192 mg kg-1). The plant height, stem diameter, root and shoot dry-mass, length and specific superficial area of roots, as well as seedlings quality index: relationship between shoot height and stem diameter, shoot height and dry-mass of shoots were evaluated. In addition, Dicksons quality index was estimated. The results showed that the tested copper doses reduce the quality of seedlings of Ateleia glazioviana; however, the Lafoensia pacari quality was better with Cu dose of 128 mg kg-1. Dose of copper influenced the growth of Ateleia glazioviana seedlings, but increased significantly the length and specific surface area of the Lafoensia pacari up to Cu dose of 128 mg kg-1. Lafoensia pacari seedlings are more tolerant to soil contamination than Ateleia glazioviana and display better quality of seedlings at high copper doses.

Concentração de nutrientes na solução do solo, sob diferentes manejos do arroz irrigado

Looking for crop alternatives management for irrigated rice possible, different systems of ryegrass straw management and aplication of fertilizers were evaluated, in relation to nutrient concentration in the solution were at there places. The experiment was conducted at the Federal University of Santa Maria, located in Central Depression Region of Rio Grande do Sul State, Brazil in the agricultural year of 2000/01. The experiment was in a randomized block with four replications, in split-split-plots design with three factors: ryegrass straw in three levels (i) no-tillage with ryegrass whole plant, (ii) ryegrass plant incorporated in soil and (iii) without ryegrass plant; time of fertilizers nitrogen and phosphorus application for rice (i) without fertilizer, (ii) fertilizer applied at the ryegrass sowing time and (iii) fertilizer applied at rice planting; and three places of sampling (i) surface water (ii) 3 cm depth and (iii) 30 cm depth in mini lysimeters. The results showed that ryegrass straw incorporation increases the potassium concentration in the water over the soil surface and contributes to percolation of calcium, magnesium, sodium, manganese and zinc in the soil profile. The concentration of there ions and potassium in the stagnant rice water remained below the established critical limits of environmental contamination stated by low.

Manejo da palha de azevém, da adubação de base e da água de drenagem na produção de arroz irrigado

Cultivation systems with minimum tillage are used to minimize red rice incidence, improving crop yield and the agricultural exploration of lowland soils. However, some limitations are present such as toxic substances due to anaerobic straw decomposition (prejudicial to rice plant establishment), as well as alterations on some available nutrients under flooded soil water conditions. The objective of this work was to compare different drainage systems; ryegrass straw management and time of fertilizer application on yield and yield components of rice plants. The experiment was conducted at the Federal University of Santa Maria, Rio Grande do Sul State-Brazil. Three ryegrass straw levels (no-tillage with ryegrass were evaluated, ryegrass plant incorporated with rotary tilling and without ryegrass plant), three fertilization conditions (without fertilizer; fertilizer applied at the ryegrass sowing time and fertilizer applied at rice sowing time) and two drainage management (conventional flooded and flooded without drainage). Results demonstrated that yield and yield components of rice production was not affected by fertilizer application at ryegrass sowing or at rice sowing. Meanwhile, deep-water drainage suppression reduces the grain yield and yield components.

Homogeneidade espacial da precipitação pluvial na bacia hidrográfica do Rio Vacacaí, RS

The objective of this research was to determine the minimum number of years with observations needed to obtain the medium number of total monthly consistent precipitation values and the area of coverage of the pluviometric station located in the Vacacai river watershed, in the Rio Grande do Sul state, Brazil. It were used the historic series of precipitation data of 13 pluviometric stations located in the area and around the watershed. The minimum number of years was calculated from the relation between the number of years with observations and the stability of coefficients of determination. The stations area of coverage was determined from the relation between the coefficients of determination of the total monthly precipitation between each station and the base station (Santa Maria), and the linear distances between the base station and each station. From those equations, the distance between stations in which 80%, 85%, 90%, 95% e 99% of the values has concordance was determined. It was found that, to have a reasonable precision in the total monthly precipitation in the Vacacai river watershed, it is necessary between 30 and 40 years of observation and, in December, January and February months the coverage of the pluviometric stations is less than 1.0km and on the other months to achieve a precision of 99% distances between 1.3 and 2.2km, 95% distances between 6.3 and 11.1km and 90% for distances between 12.5 and 22.5km.