Ronaldo Matzenauer

Crescimento de cultivares de alface conduzidas em estufa e a campo

The growth of lettuce cvs. Veronica, Marisa and Regina was analised through an experiment carried out under plastic greenhouse and under field conditions, from April 15th to June 03rd 1999, in Eldorado do Sul, Rio Grande do Sul State, Brazil. Sampling of plants started one week after transplanting and proceeded until the end of the plant cycle on a weekly basis. The lettuce cultivated under greenhouse presented more fresh and dry mass, leaf area, specific leaf area and greater number of leaves. In addition, plants cultivated under greenhouse presented a shorter cycle when compared to the plants cultivated in field conditions. The cvs. did not show any difference when cultivated under greenhouse environment, but, in field conditions, the cv. Regina presented a larger number of leaves and a larger leaf area index than the cultivars Marisa and Veronica.

Ajustes de funções de distribuição de probabilidade à radiação solar global no Estado do Rio Grande do Sul

The objective of this work was to verify the adjustment of data series for average global solar radiation to the normal, log-normal, gamma, gumbel and weibull probability distribution functions. Data were collected from 22 cities in Rio Grande do Sul State, Brazil. The Kolmogorov-Smirnov test was applied in the 792 series of data (22 localities x 36 periods of ten days) of average global solar radiation to verify the adjustment of the data to the normal, log-normal, gamma, gumbel and weibull probability distribution functions, totalizing 3,960 tests. The data of average global solar radiation adjust to the normal, log-normal, gamma, gumbel and weibull probability distribution functions, and present a better adjustment to the normal probability function.

Altitude e coordenadas geográficas na estimativa da temperatura mínima média decendial do ar no Estado do Rio Grande do Sul

The objective of this work was to estimate ten-day mean minimum air temperature (Tm) using altitude and the geographic coordinates latitude and longitude for the Rio Grande do Sul State, Brazil. Normal ten-day mean minimum air temperature of 41 counties in the State of Rio Grande do Sul, from 1945 to 1974 were used. Correlation analysis, path analysis of causal variables (altitude, latitude and longitude) on Tm, and parameters estimate of multiple linear regression equations were performed by the stepwise backward method, using Tm as dependent variable and altitude, latitude and longitude as independent variables, for the 36 ten-day periods of the year. Pearsons linear correlation coefficient between estimated and observed Tm, calculated for tem counties using data of the series of meteorological observations from 1975 to 2004 were used as independent data sets. The ten-day mean minimum air temperature may be estimated from the geographic coordinates in the State of Rio Grande do Sul. Altitude and latitude best explain the variation of the Tm.

Desempenho de quatro cultivares de morangueiro em duas regiões ecoclimáticas do Rio Grande do Sul

The choice of cultivars has important significance in achieving success in strawberries cultivation. However, the experiments with cultivars are usually carried out in conventional systems of production and not in soilless growing systems. Due to this, the present research intended to assess the performance of some strawberry cultivars in soilless growing system, inside the greenhouse, in two regions with different ecoclimatic conditions, in Eldorado do Sul (Depressao Central) and Caxias do Sul (Serra do Nordeste), in Rio Grande do Sul State. Four strawberry cultivars were tested: Aromas, Camarosa, Oso Grande and Tudla. The planting was in May 2005, and the seedlings were placed in bags containing substrate composed of 50% of peat and 50% charred rice hulls. The fertilizer was supplied by fertirrigation. Fruits were harvested when 70% of them presented red color up to fully mature. The results showed that the cultivation of strawberries in this system led to lower yield per plant than in a traditional system, but provides better use of internal greenhouse, with positive consequences in yield per area, due to the high density of plants and the facility to manage the crop. The highest productivity was obtained in Caxias do Sul (235.8 g plant-1) compared to Eldorado do Sul (196.4 g plant-1) without interaction between locations and cultivars. In Caxias do Sul, the cultivars Aromas, Oso Grande and Camarosa presented highest yield when compared to Tudla, but there was no difference in Eldorado do Sul.

Estimativa do consumo relativo de água para a cultura da soja no Estado do Rio Grande do Sul

The objective of this work was to estimate the relative water consumption (ETr/ETm) for the critical period of soybean in several sowing dates for ten places of Rio Grande do Sul state, Brazil. The maximum evapotranspiration (ETm) was estimated using the crop coefficient (Kc) while the real evapotranspiration (ETr) was estimated through the water balance, calculated for the period from 1975/76 to 2000/2001. Considering the average values of the periods, the relative water consumption varied from 0.46 in the sowing of October, in Rio Grande, to 0.74 in the sowing of December in Veranopolis. Sao Gabriel and Rio Grande are the places that present the smallest values of relative water consumption, therefore with larger risk for the production of grains. In years of strong drought, the relative water consumption, in some situations, was smaller than 0.20, evidencing the problem of water deficiency. In 46.3% of the cases the relative water consumption was classified as of high or medium risk (index ETr/ETm < 0.60 during the critical period). Rio Grande presented 63.3% of the cases with index equal to or smaller than 0.60, followed by Sao Gabriel with 61.1%, Encruzilhada do Sul with 52.6% and Julio de Castilhos with 50.8%. The places of smaller risk were Passo Fundo, Veranopolis and Santa Rosa, with indexes equal to or smaller than 0.60 happening in 30.3%, 37.5% and 38% of the cases, respectively. The sowing date with higher risk was October and with lower risk was December. For the group of the places, it can be expected that every twenty years, in about nine reduction of soybean yield should happen due to water deficiency, with variable intensity, depending on the place, year and sowing date.

Número de colheitas e comparação de genótipos de tomateiro cultivados em estufa de plástico

The objective of this study was to determine the number of harvests necessary to predict the performance of tomato (Lycopersicon esculentum) genotypes under greenhouse conditions. The genotypes Empire, Fanny, Floradade and Olympo were transplanted on October 3, 2002 and submitted to 11 harvests. The genotypes Empire, Rodas, Floradade and Olympo were transplanted on February 28, 2003 and submitted to 14 harvests. Harvests were carried through in three intervals of four days. The mass and the number of fruits and the ratio mass/number were evaluated for commercial and discarded fruits. Repeatability estimates were obtained through variance, structural, and principal component analysis. Seven harvests are sufficient to identify supe- rior genotypes for all characteristics, with 90% accuracy of the real value, in both grown conditions.

Variabilidade temporal e espacial da precisão das estimativas de elementos meteorológicos no Rio Grande do Sul

Planning agricultural activities requires that climatic risks in each location and time of year are estimated with maximum precision. In this estudy data from15 locations of Rio Grande do Sul, Brazil, were used with the objective of studing spatial and temporal variability of the precision estimates average of monthly rainfall, sunshine, solar radiation global and temperatures minimum, mean and maximum. It was estimated the estimation error (half-amplitude of the confidence interval) (EE) in percentage of estimate average monthly rainfall, sunshine, solar radiation global and temperatures minimum, mean and maximum for each month and location, which was used as a measure of precision. From the EE, for each meteorological elements, months and locations were clustered by hierarchical method of Ward. The Pearsons linear correlation coefficient between the arrays of the standardized average euclidian distance and graphics was calculated in order to check the clusters consistency. It was concluded that the precision estimates, average of months and locations, between the meteorological elements, increases in the following order: rainfall (EE=21.66%), sunshine (EE=6.74%), global solar radiation (EE=5.52%) and temperatures minimum (EE=4.40%), mean (EE=2.63%) and maximum (EE=2.27%). Results showed that there is variability in precision estimate of monthly average rainfall, sunshine, global solar radiation and minimum, mean and maximum temperatures in Rio Grande do Sul, both in temporal and spatial scale. Estimates based on 30 years data are less precision in April, May, June, July, August and September in relation to the others.

Coordenadas geográficas na estimativa das temperaturas máxima e média decendiais do ar no Estado do Rio Grande do Sul

The objective of this research was to estimate ten-day maximum (Tx) and mean (Tm) air temperature using altitude and the geographic coordinates latitude and longitude for the Rio Grande do Sul State, Brazil. Normal ten-day maximum and mean air temperature of 41 counties in the State of Rio Grande do Sul, from 1945 to 1974 were used. Correlation analysis and parameters estimate of multiple linear regression equations were performed using Tx and Tm as dependent variable and altitude, latitude and longitude as independent variables, for the 36 ten-day periods of the year. Pearsons linear correlation coefficient between estimated and observed Tx and Tm, calculated for tem counties using data of were used as independent data sets. The ten-day maximum and mean air temperature may be estimated from the altitude and the geographic coordinates latitude and longitude in the State of Rio Grande do Sul.

Variabilidade temporal e espacial do tamanho de amostra da temperatura mínima do ar no Rio Grande do Sul, Brasil

The aim of this work was to verify temporal and spatial variability of the size sample of the monthly average of air minimum temperature, in 37 localities of the Rio Grande do Sul State, Brazil. The minimum temperature data were collected from 1931 to 2000. It was calculated the sample size, in each month and locality. Localities and months were clustered by the complete linkage method. There are variability temporal and spatial of the size sample (number of years) of the monthly average of air minimum temperature in the Rio Grande do Sul State. Greater sample size occur in the months of May, June and July, with gradual reduction up to January and December. There are variability in the size sample among locaties in the Rio Grande do Sul State.

Dimensionamento da amostra para a estimação da média de precipitação pluvial mensal em diferentes locais do Estado do Rio Grande do Sul

It was used data from 19 locations of the Rio Grande do Sul State, Brazil, collected from 1953 to 2007, with the objective to determine the sample size to estimate the average monthly rainfall. The central tendency, variability and asymmetry was calculated for each of the 228 time series (12 months x 19 locations) and the aleatory and normality data were tested. Then it was verified the homogeneity of variance among months in each locality and among places in each month and it was determined the sample size to estimate the average monthly rainfall in each month and locality. The sample size (number of years) to estimate the average monthly rainfall is dependent on the month and locality. One concluded that 51 years of data are enough to predict the average monthly rainfall, with an estimation error equal to 25% of estimated average, with a degree confidence of 95%.