Paula Machado dos Santos

A precisªo experimental relacionada ao uso de bordaduras nas extremidades das fileiras em ensaios de milho

Seven experiments of corn cultivar competition were carried out to quantify the experimental precision improvement by evaluating border plants at the ends of rows of corn trials. The experiments were conducted during 2000 and 2001 grown seasons at the experimental area of the Fitotecnia Department, Federal University of Santa Maria, RS, Brazil. Each cultivar was replicated three times in plots of two rows of 5.0m separated by 0.80m following a randomized complete block design. The 0.5m of the ends of the same plot rows was considered as border plants and was separated evaluated. Data on grain yield of plot and total yield including border plants were used to verify the statistical model presuppositions as well as the analysis of variance and Scott-Knott cluster analysis. The Tukey least significance difference (LSD) statistic was used as experimental precision indicator. The significance of the LSD statistic between two experiments was tested by the F test. All experiments followed the statistical model presuppositions. The inclusion of border plant data did not change experimental precision of corn cultivars competition trials.

Eficiência operacional na colheita mecanizada em lavouras de arroz irrigado

The objective of this research was to evaluate the time efficiency and the field efficiency of the harvesting operation in rice fields, located in the region of Depressao Central of Rio Grande do Sul, Brazil. In the summer of 2008/2009, 19 operations were evaluated, being fifteen fields of them with land level and four without land level. The operation data were collected through the use of stopwatch, a clip board to record observations and with a signal receiver of GPS (Global Positioning System). There was no significant difference in the 5% level of probability of error between operations with land level and operations without land level. The field efficiency was calculated through the methodology used by GRISSO et al. (2002), and have been found the average of 65.2%, the time efficiency was determinate based on the concept of Hunt (2001), which have determined an average of 75.7%. Unload making combining with operation increase the field efficiency.

Cronograma de amostragem de plantas de alface hidropônica para ajuste de curvas de crescimento

The fitting of growth curves for lettuce plants requires many samplings within o time interval, while can restrict the number of studied treatments. With the aim o determine sampling chronogram hidroponic lettuce for the fitting of growth curves until maturation of seeds. Two greenhouse trials were carried out in spring an autumn, at UFSM experimental area, Santa Maria, RS. Different sampling interval were simulated using the fitting of a daily model. The optimum sampling interval were determined by comparing daily sampling model with simulated sampling model by F test. Simulations were carried between out for the following variables: total leaf, root and leaf area phytomass. Based on trials carried out during spring it is recommended sampling in intervals of three (total), eight (leaf), 20 (roots) and nine (leaf area) days and for carried out in autumn the sampling interval should be of two, 11, 12 and 11 days.

Compliance of the command operations of national agricultural tractors with the NBR ISO 4253 standard

The aim of this study is to compare the location of command operations in agricultural tractors, measured through the Seat Index Point (SIP), with NBR ISO 4253 norms - accomodation of operator seat. This analysis included agricultural tractors manufactured in Brazil from all commercial brands available in the country. The clutch pedal was the command that best met the requirements of norm NBR ISO 4253 (51.4%), followed by the brake pedals (48.2%) and the accelerator pedal (14.3%). Only 23.0% of the operation posts sampled met the requirements of the norm, placing the location of the steering wheel within the limits of the optimal area specified. The best compliance with NBR ISO 4253 was found in the operation posts of New Holland models TS100, TS110 and TS120 (cab model) (100%), followed by the operation post of John Deere models 5605 and 5705 (87.5%), as well as the operation post of Massey Ferguson models MF275, MF283, MF290, MF292, MF297, MF299, MF5275, MF5285 and MF5290, (cab model).

Cronograma de amostragem de alface cultivada em hidroponia para ajuste de curvas de crescimento vegetativo

O objetivo deste trabalho foi determinar o cronograma de amostragem de plantas de alface hidroponica, para ajuste de curvas de crescimento durante o periodo vegetativo. Foram realizados dois cultivos de alface, variedade Regina, de 8/9/2004 a 19/11/2004 (primavera/verao) e 22/2/2005 a 24/5/2005 (verao/outono), em estufas de plastico do Dep. de Fitotecnia, da UFSM, Santa Maria, RS. A partir do ajuste do modelo co-seno com amostragem diaria, registrada como padrao, diferentes intervalos entre as amostragens foram simulados para o ajuste do mesmo modelo. A fim de se encontrar o intervalo adequado, foi comparada a variância de falta de ajuste do modelo de amostragem diaria com as variâncias de falta de ajuste dos modelos com diferentes intervalos de amostragens pelo teste F. Os cronogramas de amostragens para ajuste de curvas de crescimento de plantas de alface sob hidroponia, para experimentos de primavera/verao e verao/outono, possuem intervalos iguais a dois dias, para fitomassa seca total da planta e da folha; intervalos de quatro dias, para fitomassa de raiz; e, diariamente, para area foliar.

Adequação de ciclo e estatura de planta é essencial para a comparação de genótipos de milho

Genotype effects can result in recommendation mistakes in corn (Zea mays) competition trials. The objective was to verify if corn genotypes were well arranged and their consequences to mean comparisons. Six experiments were carried out at the experimental area of the Federal University of Santa Maria with early, medium and late cycle corn genotypes during 2000/2001 grown season. The experimental design was a factorial (genotype in main plots and plant density in sub-plots) in a randomized complete block with three replications. The mathematical model assumptions were adequate in most cases. Genotype arrangements were not adequate for cycle and plant height, increasing experimental errors and reducing statistical power of mean comparisons. Corn genotypes with different cycle and/or plant height should not be compared in the same plant density and trial.

Validação de teorias de simulação para operações com escarificadores em solo argiloso no planalto do Estado do Rio Grande do Sul, Brasil

The objective of this research was studied theories used specially to simulate real field situations contrasted by empiric data obtained in real real working conditions in mechanized agricultural clay soil with the results obtained in similar studies conducted in other countries. We tried to the graphical representation of the demand required traction force and slippage through the use of Prediction software version 1.0, contrasted with results obtained by applying the theories of prediction Cn, Bn and Mn. Predictive theories Cn, Bn and Mn have good correlation with experimental values, however, there is an overestimation by the theory compared to the values measured experimentally, for traction force and slippage, causing a tractor design inadequate.

SISTEMAS DE IRRIGAÇÃO E RECIPIENTES PARA A PRODUÇÃO DE MUDAS DE FUMO EM HIDROPONIA

Com o objetivo de avaliar sistemas de irrigacao e recipientes para a producao de mudas de fumo em hidroponia, realizou-se experimento em casa-de-vegetacao no Departamento de Fitotecnia da Universidade Federal de Santa Maria - UFSM. As mudas de fumo foram produzidas em piscinas rasas nas dimensoes 1,0 m de largura e 2,0 m de comprimento e 0,10 m de profundidade. O experimento foi um bifatorial 2 x 4 em delineamento inteiramente casualizado com parcelas subdivididas e quatro repeticoes. As parcelas principais foram constituidas pelos sistemas de irrigacao permanente, com lâmina de agua e sistema de irrigacao intermitente, sem lâmina de agua, e as subparcelas foram constituidas por quatro formas de acondicionamento de substratos: bandejas de plastico preto com 25 celulas preenchidas com substrato organo-mineral “Plantmax®”, bandeja de plastico preto preenchida com espuma fenolica 2 x 2 x 2 cm, placa de espuma fenolica em duas dimensoes 2 x 2 x 2 cm e 2,5 x 2,5 x 3,0 cm. A semeadura foi realizada em 30 de junho de 2005 e as amostragens foram feitas aos 30, 37 e 44 dias apos a emergencia. Os sistemas de irrigacao intermitente e permanente nao diferiram significativamente entre si para a producao de mudas de fumo em hidroponia. O recipiente bandeja com substrato organo-mineral “Plantmax®” proporciona mudas de fumo com maior estatura, numero de folhas, area foliar e fitomassa seca de parte aerea. Palavras-chave: Nicotiana tabacum, qualidade de mudas, substratos, cultivo sem solo. ABSTRACT With the purpose to evaluating systems of irrigation and containers for the production of tobacco runners in hydroponics, an experiment was conducted at a greenhouse at the Departamento de Fitotecnia at the UFSM. The tobacco runners were produced in flat pools, 1 m large, 2 m long and 0,10 m deep. It was used an entirely randomized delineation, with subdivided plot in 2 x 4 factorial project, with four replications. The main plot were constituted by permanent irrigation system, with water blade and intermittent irrigation system, without water blade. The splitplot were constituted by four forms of substratum preservation: black plastic trays with 25 cells filled with mineral-organic substratum “Plantmax®”, black plastic tray filled with phenolic foam and phenolic foam in two dimensions (2 x 2 x 2 cm and 2,5 x 2,5 x 3,0 cm). The sowing was carried through in June 30, 2005 and samples were taken at the 30 th , 37 th and 44 th days after the emergency. The intermittent irrigation system and the permanent irrigation not presented a significant statistical difference for the production of tobacco runners in hydroponics. The container trays filled with organic mineral substratum “Plantmax®” presented runners with better stature, number of leaves, leaf area and dry plant mass. Key words: Nicotiana tabacum, quality of runners, substratum, soiless cultivation.