Bruno Giacomini Sari

Aplicação aérea de fungicidas na cultura do arroz irrigado com diferentes bicos de pulverização

In the harvest year of 2007/2008 a study was carried to evaluate the droplets deposition and penetration throughout water sensible cards and gas chromatographic analysis. Were used the hydraulic nozzle, electrostatic nozzle and rotary-disk atomizer spraying systems, with different volumes of spray solution. Aerial applications were performed at R3 stage using the aircraft Ipanema EMB-202 and the fungicide trifloxystrobin + propiconazole. Throughout the lection of the water sensible cards was determinate the droplet density, the medium numeric diameter, the medium volumetric diameter, the relative amplitude and the percentage of droplet penetration in the canopy. Chromatographic analysis was also performed to determinate the fungicide penetration into the biological target. The pulverization systems hydraulic nozzle 20L ha-1 and 30L ha-1 and the electrostatic system 10L ha-1 demonstrated higher droplet density in the upper third. The rotary-disk atomizer 15L ha-1 showed higher droplet density in the mid and low third. To the medium volumetric diameter, the electrostatic nozzles and the rotary-disk atomizer showed the lowest values. The higher homogeneity in the upper third was attained with rotary-disk atomizer at the pulverization rates of 6L ha-1 and 10L ha-1. The chromatographic analysis showed that the higher quantity of product retention was obtained with the electrostatic system at the pulverization rate of 10L ha-1 in the lower plant extract.

Heterocedasticidade entre fileiras e colheitas de caracteres produtivos de tomate cereja e estimativa do tamanho de parcela

O presente estudo teve por objetivo avaliar a heterocedasticidade entre as fileiras de cultivo e entre as colheitas em tomate cereja cultivado em ambiente protegido e determinar o tamanho otimo de parcela para avaliar as caracteristicas produtivas da cultura. Para isso instalou-se dois ensaios de uniformidade em estufas plasticas, cada uma contendo oito fileiras espacadas 1 m entre si. Utilizou-se o hibrido Lili, e as mudas foram espacadas em 0,5 m. Foram realizadas tres colheitas e as analises foram realizadas com base nas colheitas individuais e agrupadas. A homocedasticidade entre as fileiras de cultivo e entre as colheitas para cada fileira de cultivo foi obtida pelo teste de Bartlett. O tamanho de parcela (em numero de plantas) foi calculado para cada fileira e colheita (individual ou agrupada). Observou-se heterocedasticidade entre as fileiras de cultivo para pelo menos um caractere em todas as colheitas (individuais ou agrupadas). Ocorreu heterocedasticidade entre as colheitas dentro de cada fileira de cultivo para todas as variaveis. Estas duas caracteristicas justificam a necessidade de se estimar o tamanho otimo de parcela para cada situacao. O tamanho de parcela (em numero de plantas) foi diferenciado entre as fileiras e as colheitas, sendo esta estimativa menor quando as tres colheitas sao agrupadas. E recomendado o agrupamento das colheitas e a adocao de parcelas contendo sete plantas de tomate, independente da fileira de cultivo.

TAMANHO DE AMOSTRA PARA AVALIAR A SEVERIDADE DE BRUSONE DA FOLHA EM EXPERIMENTOS COM ARROZ IRRIGADO

The aim of this study was to determine the sample size needed to assess the severity of leaf blast in rice in experiments with different fungicide treatments. The severity and the area under the disease progress curve data of three chemical disease control treatments carried out in Rio Grande do Sul, were used in the study. Analysis of variance was performed to verify whether the severity of the disease differed between treatments. The spread of disease was was also found to be different between treatments and assessments, using the variance/mean ratio and Morisita index. The spatial distribution of the disease among the treatments and during the evaluations is important for the choice of the equation used to calculate the sample size. The spatial distribution of the disease was not the same across the experiments, and it varied between treatments and evaluations. Thus, we decided to use a formula that was not associated with distributions to indicate the spatial distribution (negative binomial or Poisson) of the disease in the field. The sample size to estimate the average of rice leaf blast severity varied between treatments and evaluations. The area under the disease progress curve is necessary to be determined to reduce the number of samples needed. Thus, it is recommended to assess 293 sheets to estimate severity, and 63 to estimate AUDPC at 20% error.

Caracterização da pulverização de fungicida na cultura do trigo com pontas hidráulicas e atomizadores rotativos de discos

The study aimed to evaluate the pulverization characteristics of the hydraulic nozzles and rotary-disk atomizer with different spraying rates on wheat crops, and their operational capacity. For this reason were installed two experiments, on the harvest years of 2009 and 2010. In first year was used the cultivar Fundacep 30, and in the second year the cultivars Pampeano and Nova Era. The experiments evaluating the pulverization with flat nozzles and hollow cone spray nozzle, both with the pulverization rate of 120 L ha-1, and rotary-disk atomizer with 24 and 34 L ha-1 in low volume in oil. The evaluated parameters were the droplet density and the medium volumetric diameter on the upper, mid and lower third throughout the analysis of water sensible cards. Also, was calculated the operational capacity of the traits. The results showed that the rotary-disk atomizer with 24L ha-¹ showed a higher droplet density on the upper third, however, there was no difference among the mid and lower thirds treatments. The rotary-disk atomizer presented droplets of smaller medium volumetric diameter compared to the hydraulic nozzles that presented high droplet heterogeneity. The higher operational capacity was achieved with the atomizers, due the lower spray volume used by this equipment.

Uniformity trials size for estimating cherry tomato plot size

The aim of this study was to determine how the size of the uniformity trial influences the estimation of cherry tomato plot size. The size of plot required to evaluate the mean length of fruit per plant, mean fruit width per plant, mean fruit weight per plant, number of bunches per plant, number of fruits per bunch, number of fruits per plant and total weight of fruits per plant was estimated in uniformity trials in two greenhouses: large (250 m²) and small (200 m²). In each greenhouse and row, and for each variable, 3000 plot size estimates were obtained by resampling and used to determine of 97.5 and 2.5% percentiles. Each row needs to be treated as a specific uniformity trial because of significant row variability. It is recommended that uniformity trials are carried out on 35 plants in the large greenhouse and 23 plants in the small greenhouse in order to estimate cherry tomato production variables at a confidence interval of 30% of the mean.

Nonlinear regression for description of strawberry (Fragaria x ananassa) production

ABSTRACT The aim of this study was to select growth models to describe strawberry (Fragaria x ananassa)fruit production. To do this, data on 16 treatments (combination of 2 cultivars [Albion and Camarosa], 2 origins [National and Imported], and 4 organic substrates mixed [70% crushed sugar cane residue + 30% organic compost, 70% crushed sugar cane residue + 30% commercial substrate, 70% burnt rice husk + 30% organic compost, and 70% burnt rice husk + 30% commercial substrate]) conducted in a Randomized Complete Block Design (RCBD) with 4 replicates were used. Different parameterizations of the Logistic, Gompertz, and von Bertalanffy models were adjusted for number and weight of fruits per plant (g) accumulated in multiple harvests. The model adjustment and parameter estimation were obtained by ordinary least squares, using a Gauss Newton algorithm. The selection of the best model was chosen by intrinsic and parametric nonlinearity. Among the adjusted nonlinear models, the best adjustment for both variables was achieved by the parameterization 2 of the Logistic model and parameterization 1 of the Gompertz model, because they had lower results with less parametric and intrinsic nonlinearity. However, care should be taken when using the Gompertz model because it tends to overestimate the production estimate and may cause misunderstandings in interpretation.

The effect of types and split of urea on yield indicators and yield components of maize

Maize is one of the most important cereals in the world. The productive potential of this crop is closely associated with nitrogen (N) fertilization, thus, studies focused on this subject are important in the development of cropping strategies. The aim of this work was to evaluate the effects of N split and different type of urea on important agronomic traits of the maize crop. A randomized complete block design in a 2×2+1 factorial treatment design with four replications was used. The factorial levels were composed of two types of urea (common and coated) and two nitrogen splits (V3 and V3+V8), plus the control treatment (without urea application). Important agronomic traits such as grain yield, biological productivity, and yield components were assessed. It was verified that there is no difference between the common or coated urea on grain yield and its components. On the other hand, the split of nitrogen into V3 and V8 stages is an efficient strategy to improve grain yield as well as important features as the number of rows per ears and harvest index. Thus, by using this management system farmers can achieve a more efficient nitrogen use.