Gilmar Ribeiro Nachtigall

Nitrogen and Potassium Fertilization Affect Apple Fruit Quality in Southern Brazil

Abstract Nitrogen (N) and potassium (K) are usually found in higher concentrations than other macronutrients in apple (Malus x domestica Borkh) fruits and are most frequently associated with changes in fruit quality. The aim of this article was to evaluate the effects of N and K fertilization on some fruit quality attributes of Fuji apple. The experiment was conducted at São Joaquim, State of Santa Catarina, Brazil, during 2004 and 2005. A factorial design was used with N and K annual fertilizer rates (0, 50, 100, and 200 kg ha−1 of N and K2O) replicated in three orchards. Fifteen days prior to harvest, three fruit samples were collected from each treatment and site. One sample was used for total soluble solid content (TSS), titratable acidity, pulp firmness, and fruit color parameter analyses, and the other samples were refrigerated in a conventional atmosphere for 3 and 6 months for subsequent determination of fruit quality. Nitrogen fertilization negatively affected fruit color, flesh firmness, and TSS content. These same variables were positively affected by K fertilization, except for flesh firmness.

Sequential extraction and availability of copper in Cu fungicide-amended vineyard soils from Southern Brazil

The continuous use of cupric fungicides in vineyards, mainly copper sulfate (as a component of the bordeaux mixture), has increased Cu concentration in soils to levels near or even above the maximum established by the Commission of Soil Chemistry and Fertility of the States of Santa Catarina and Rio Grande do Sul, Brazil. Besides the total content, the fractions of the element along the soil profile must be known, because the total content of Cu in the soil is not sufficient to express its environmental impact. The objective of this study was to evaluate the variation of Cu contentes along the soil profile and its speciation and partitioning in 29 soil samples from vineyards in the state of Rio Grande do Sul, Brazil. Samples were collected in areas cropped with vineyards older than 15 years that had been frequently treated with the bordeaux mixture. These samples were from Nitosols, Acrisols, Cambisols and Leptosols and were analysed by sequential extractions and several chemical extractors. Soils had diverse chemical and physical attributes: clay content in the plowed layer (0-0.2 m) ranged from 120 to 610 g kg(-1), pH ranged from 5.3 to 7.3 and organic carbon contents varied from 2.9 to 51 g dm(-3). Among the 29 samples, 16 had the total Cu above the maximum limit allowed by the European Community regulations (140 mg kg(-1)). The average amount of Cu bonded to the oxide fraction accounted for 49.5% of the total Cu.

Copper concentration of vineyard soils as a function of pH variation and addition of poultry litter

Copper (Cu) concentration was evaluated as a function of pH variation and addition of poultry litter to a Dystrophic Lithic Udorthent and a Humic Dystrudept from the state of Rio Grande do Sul, Brazil, cultivated with vines treated with successive applications of Cu-based product. Samples were collected from the surface layer (0 to 10 cm). Soluble Cu concentration was determined using DTPA and Mehlich III as extractants, and exchangeable Cu was determined in CaCl2. The availability of Cu was mainly affected by the soil pH. CaCl2 extractant had the best correlation with Cu concentration in contaminated soils, according to treatments applied. The addition of poultry litter did not reduce Cu availability in these soils. Total soil Cu content varied between 1,300 and 1,400 mg kg-1 in both soils. Copper available fractions, extracted by DTPA, CaCl2 and Mehlich III, averaged 35, 0.2 and 63%, respectively, of the total Cu present in the soil.

Testing and validation of methods for the diagnosis and recomendation integrated system for Signal grass

O Sistema Integrado de Diagnose e Recomendacao (DRIS) permite a interpretacao dos resultados de analise foliar, utilizando relacoes entre nutrientes, ao inves da concentracao absoluta e isolada de cada um deles, utilizada pelo criterio de faixa de suficiencia. Objetivou-se avaliar tres procedimentos de calculo dos indices DRIS, bem como verificar a eficiencia do DRIS como metodo de interpretacao de resultados de analises de folhas da Brachiaria decumbens (capim-Braquiaria). O estudo foi desenvolvido com os resultados de seis experimentos realizados em casa-de-vegetacao em Piracicaba, SP, com solucao nutritiva. Foram empregadas as concentracoes de N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn nas amostras de lâminas foliares recem-expandidas do capim. Para a validacao do metodo DRIS foram utilizados resultados de um experimento com aplicacao de doses de nitrogenio e enxofre realizado com o mesmo capim proveniente da Fazenda Mundo Novo, em Brotas, SP. Os indices DRIS foram calculados por dois criterios para escolha da ordem da razao dos nutrientes (valor F e valor R) e tres formas de calculo das funcoes dos nutrientes (metodos de Beaufils, Jones e Elwali & Gascho). O Indice de Balanco Nutricional (IBN), calculado a partir das normas geradas, apresentou coeficientes de correlacao negativos e significativos com a produtividade nas combinacoes de metodos testados e os metodos DRIS propostos por Beaufils, Jones e Elwali & Gascho foram eficientes em detectar concentracoes que revelam a deficiencia ou o excesso dos nutrientes.

Formas de cobre em solos de vinhedos em função do pH e da adição de cama-de-frango

The objective of this study was to evaluate the distribution of forms of copper as affected by pH and poultry litter addition in samples of surface layers (0 to 10 cm) of a Dystrophic Lithic Udorthent and a Humic Dystrudept, both from Serra Gaucha (Rio Grande do Sul highlands), Brazil, cultivated for more than 15 years with vines treated with successive applications of copper-based products. To evaluate the effects of pH variation and soil organic matter content in copper forms, five doses of HNO3 (50, 100, 200, 300 e 400 mmol kg -1 ) and four doses of poultry litter in dry basis (10, 20, 40 e 80 t ha -1 ) were added to the soils. The following fractions were evaluated: exchangeable; bound to organic matter; bound to Fe, Al, and Mn oxides; and residual. The largest proportion of copper of the soil was bound to organic matter fraction (from 70 to 80%). As the pH decreased from 6.8 to 3.8, the copper exchangeable contents increased, while copper bound to organic matter, oxides, and residual fractions decreased. The application of poultry litter did not significantly affect the distribution of forms of copper in both soils, except for the exchangeable fraction.

DRIS Use on Apple Orchard Nutritional Evaluation in Response to Potassium Fertilization

Abstract The aim of this work was to use the diagnosis and recommendation integrated system (DRIS) method to evaluate the nutritional status of an apple orchard, cv. Gala/MM106, at Vacaria, State of Rio Grande do Sul, Brazil. Treatments consisted of four levels of annual maintenance potassium fertilization. Data on fruit production and fruit pellicle color were restored from 1995 to 2000, as well as the data on leaf macro and micro-nutrient concentrations. The DRIS indices and nutritional balance index (NBI) for each nutrient were determined using three methods: Beaufils, Jones, and Elwali and Gascho. The results showed that (i) the NBI, calculated from the generated norms, were negatively correlated negative correlated with productivity and fruit coloration, and (ii) the DRIS method, described by Elwali and Gascho and using the F value, was the most suitable for apple tree orchards, because the NBI values obtained with this method best indicated the nutritional status of the plants and provided a more accurate nutritional diagnosis.

Norms for the diagnosis and recommendation integrated system for Signal grass

The Diagnosis and Recommendation Integrated System (DRIS) has been proved efficient as a method for nutritional diagnosis in several crops. However there is a lack of information on the use of DRIS for tropical forage grass. The aim of this paper was to establish norms for interpretation of results of analysis from recently expanded leaf laminae of Brachiaria decumbens Stapf. (Signal grass), through the DRIS method. To establish DRIS norms, concentrations of N, P, K, Ca, Mg, S, Cu, Fe, Mn, and Zn and the relative production obtained in six experiments conducted in greenhouse using nutrient solution and silica as substrate were considered. DRIS indices were calculated using two criteria in order to choose the ratio order of nutrients: F value - ratio of variance for the relationships among nutrients between the reference group and the low productivity group; and R value - correlation coefficients between the productivity values and the relationship among the pairs of nutrients, and three forms of calculation for the functions of nutrients (methods of Beaufils, of Jones, and of Elwali & Gascho). The two criteria to choose the ratio order of nutrients selected different ratios between pairs of nutrients; the nutrient concentrations were positively and significantly correlated with the respective DRIS indices, except for N; and DRIS norms are useful for the nutritional diagnosis of the ten studied nutrients in leaf laminae of Signal grass.

Extração seqüencial de Mn e Zn em solos em função do pH e adição de cama-de-frango

The availability of cationic micronutrients and their distribution in different soil fractions are affected by many soil attributes, such as pH and organic matter (OM) contents. Available Zn and Mn contents, obtained with three extractors, and Zn and Mn fractionation were evaluated in samples from surface layers (0 to 10 cm) of a distrophic Lithic Udorthent and a Typic Haplumbrept, as a function of pH variation and addition of poultry litter. Both soils are cultivated with vines, in Rio Grande do Sul highlands (Serra Gaucha), Brazil. As the pH decreased from 6.8 to 3.8, Zn and Mn available and exchangeable (by sequential extraction) contents increased. On the other hand, Zn and Mn contents bound to OM fraction decreased. The addition of poultry litter promoted an increase in the contents of both available and exchangeable Zn and Mn. The largest proportion of Mn was bound to OM (35%) and to residual fraction (30%), while the largest amount of Zn was in the residual fraction (55%). Zn and Mn extracted by DTPA, CaCl2 0.01 mol L-1, Mehlich III had a linear correlation with the exchangeable and with the OM-bound contents.

Disponibilidades climáticas para macieira na região de Vacaria, RS

This study aimed to evaluate the variability and temporal tendency for the main climate parameters - air maximum, minimum and mean temperatures, chilling hours (bellow to 7°C), pluvial precipitation, and relative air humidity - in the 1983-2009 period, focusing to evaluate the climate conditions for Gala and Fuji apple groups, in Vacaria, Brazil. Daily weather data in the 1983-2009 series were compared to climate means of the 1931-1960 and 1961-1990 periods, for analyzing the temporal trends. The annual pluvial precipitation showed significant differences in comparing the 1983-2009 series to both the climate means, with increments of 479 and 256mm, respectively. There were no significant differences in monthly air temperatures among the analyzed periods. The pluvial precipitation in spring season and the annual mean of minimum air temperature showed significant tendencies for increasing. The mean number of 657chilling hours was from May to August. The minimum number of chilling hours defined zoning of agroclimatic is achieved in most of the years, in Vacaria, however, does not mean the natural breaking of bud dormancy the apple tree. Otherwise, the number of chilling hours had a significant tendency for reducing.

Classification of Apple Tree Disorders Using Convolutional Neural Networks

This paper studies the use of Convolutional Neural Networks to automatically detect and classify diseases, nutritional deficiencies and damage by herbicides on apple trees from images of their leaves. This task is fundamental to guarantee a high quality of the resulting yields and is currently largely performed by experts in the field, which can severely limit scale and add to costs. By using a novel data set containing labeled examples consisting of 2539 images from 6 known disorders, we show that trained Convolutional Neural Networks are able to match or outperform experts in this task, achieving a 97.3% accuracy on a hold-out set.