David José Miquelluti

Physiological potential of common landrace bean seeds (Phaseolus vulgaris L.)

The objective of this study was to characterize the physiologic potential of common landrace bean seeds. The seeds were produced in the 2007/2008 growing season with 26 genotypes from Lages-SC. The seed physiological potential was evaluated from the percentage germination, before and after accelerated ageing, the weight of 100 seeds, electrical conductivity, the length of the primary root and field emergence. The genotypes were grouped into classes using the Scott-Knott test and compared with a standard (commercial cultivars) using the Dunnett test, which indicated the BAFs 36, 55, 75, 102 genotypes as having a high physiological potential. Under field conditions, most landrace genotypes were adapted to environmental conditions, except for BAFs 4, 7, 23. The correlation analysis showed a positive association between the percentage initial germination and the length of the main root, and a negative correlation with the weight of 100 seeds. The genotypes with a lower seed mass showed more vigor.

Analysis of probable monthly rainfall in the municipality of Lages, SC

In this study, monthly rainfall time-series with 80 years of collected data were analyzed and adjusted using gamma distribution in order to determine the expected monthly rainfall for Lages, in the State of Santa Cararina. The method of adjustment of model was used to estimate α and β parameters of gamma distribution, and Kolmogorov-Smirnovs test assessed the models fitting to the data. Gamma distribution fitted to observed data of all months of the year (p x). The results showed that the monthly mean rainfall, for all months of the year, occurred at probability level of 31.93% with variation coefficient of 3.63%. Considering these results, it is proved that the found mean values should not be used as parameters in agricultural projects. For all months of the year, the difference between monthly mean rainfall and probable rainfall were 64.49 mm (51.3%) and 73.03 mm (58.1%), at probability levels of 75 and 80% respectively.

Homeopathic and high dilution preparations for pest management to tomato crop under organic production system

Tomato crops (Solanum lycopersicum) under conventional production system are constantly treated against pest and diseases, with organic synthetic pesticides that are used may cause serious disturbance to environment and human health. This research was carried out in order to study the effect of homeopathic and high dilution preparations on pests and diseases management of tomato crop under organic production system. Two experiments were conducted under field conditions and one in greenhouse. All of them in randomized block design with the cultivar Santa Cruz Kada. The treatments consisted of homeopathic preparations Staphysagria, Arsenicum album, Sulphur, Arnica montana, high dilution preparations of Solanum lycopersicum and Solanum aculeatissimum, at the decimal (DH) or centesimal (CH) scale of hahnemanian high dilution. Bordeaux mixture, cupric preparation, and Bacillus thuringiensis were also included in weight doses. The preparation Arnica montana 12DH increased the tomato yield under field conditions. The damage incidence of small borer was efficiently reduced with applications of Sulphur 12CH that equalling to B. thuringiensis. The same treatment did not reduce the large borers. B. thuringiensis reduced also the septoria leaf spot incidence in the field. In greenhouse, the high dilution preparation of tomato at 12DH completely suppressed the septoria leaf spot and drastically reduced the same disease at 24DH. The homeopathic and high dilution preparations have the potential to be effective on replacing pesticides that are used on tomato, and could be suitable to fill legal requirement for organic production system.

Downward movement of soil cations in highly weathered soils caused by addition of gypsum

Abstract Besides supplying calcium (Ca) and sulfur (S) to plants, gypsum has recently been used in agriculture to ameliorate some soil physical and chemical properties, especially to alleviate aluminum phytotoxicity in subsoils. When applied in large quantities, however, gypsum may leach significant amounts of nutrients from the plow layer. This study was conducted to assess the effect of gypsum addition to the soil on the magnitude of cation leaching as well as the relationship of leaching with some soil properties in a group of seven Brazilian soils. Rates of gypsum equivalents to 0, 5.0, 10, and 20 t ha−1 (0, 2.5, 5.0, and 10 g kg−1) were mixed with triplicate soil samples consisting of 3.0 kg of dry base soil. After 60 days of incubation at room temperature (15–25°C), the experimental units were packed into polyvinyl chloride leaching columns (32‐cm‐high×10 -cm-diameter) at a density of 0.9 g cm−3. Thereafter, they were percolated once a week with a volume of distilled water equivalent to 1.5 times the total soil porosity over 11 weeks. Soil samples were collected before the first and after the last percolation, for chemical analysis. Averaged across soils, 11 percolation events leached about 26% of each Ca, magnesium (Mg), and potassium (K) from the treatment without gypsum. Averaged across soils and rates, addition of gypsum leached 41–94% of added Ca, 13–90% of exchangeable Mg, and 13–58% of exchangeable K, and the highest losses occurred on the sandiest soils. The relationship between soil parameters and Ca leaching varied with gypsum rate: in the treatments that received gypsum, leaching was negatively related to cation exchange capacity (CEC), clay, and organic matter, and positively correlated with sand; in the treatment with no gypsum, leaching correlated with the same parameters above, nevertheless, all coefficients presented opposite signs. Leaching of K caused by gypsum was negatively associated with clay and positively with sand, whereas leaching of Mg was poorly correlated with any soil parameter. Gypsum is a good source to promote high and fast downward movement of Ca in the soil profile, but rates must be cautiously chosen because of excessive leaching of Mg especially on soils with low CEC.

Capacidade máxima de adsorção de fósforo e constante de energia em Latossolo Bruno em razão de diferentes ajustes do modelo Langmuir

Maximum phosphorus adsorption capacity (Pmax) is a useful tool for characterizing the phosphorus (P) sorption of soils, and the Langmuir model, which allows this estimate, has widespread use. However, estimated values of Pmax and the binding energy constant (k) may be quite different when fitted to non-linear or linearized Langmuir models, or models with single or multiple regions. The objective of this study was to compare the effect of using different methods to fit the Langmuir model to the estimation of Pmax and k values. A single soil with high Pmax was mixed with increasing amounts of sand, producing artificial soils with increasing P adsorption capacities but with the same clay mineralogy. Soil from the B horizon of an Oxisol containing 800 g kg-1 clay was mixed with washed sand in amounts necessary to obtain samples with 0, 200, 400, 600, and 800 g kg-1 of clay. These artificial soils were incubated for 30 days with lime to raise the pH in water level to 6.0. The adsorption isotherms were constructed and the data fitted using the following Langmuir model approaches: NLin - nonlinear with a single region; L-1R - linearization with a single region; L-2RG - linearization with two regions and graphical adjustment; L-3RG - linearization with three regions and graphical adjustment; and L-2RE - linearization with two regions and statistical fitting. The results showed that the Pmax values estimated by all methods were dependent on the clay content of soils and could be used to characterize the P adsorption of the soil. However, when fitted to more than one adsorption region, the Pmax values for the last region were significantly higher than those observed after incubation of the soil with different P levels. Therefore, the Pmax of the last region in multi-region models may not be appropriate for characterizing soil P adsorption capacity. As expected, the k values were dependent on soil clay content in the first (or single) region of the linearized models, but they did not follow this trend in the nonlinear model. Thus, caution should be taken in interpretation of the k constant fitted to nonlinear models.

Atributos químicos do solo e produtividade de videiras alterados pelo manejo de coberturas verdes na Serra Gaúcha

Soil management can have effects on nutrient availability and fruit yield. The objective of this study was to evaluate the effect of phytomass management forms of different cover crop species on soil chemical properties related to organic matter, nutrient availability, and on grapevine yields. The experiment was carried out in Embrapa Uva e Vinho, in Bento Goncalves, RS, in Southern Brazil, on a Haplic Cambissol, in a vineyard established in 1989, using White and Rose Niagara grape in a horizontal overhead trelling system. The treatments established in 2002 were three cover crops: spontaneous native species, black oat (Avena strigosa), and a mixture of white clover (Trifolium repens) + red clover (Trifolium pratense) + annual ryegrass (Lolium multiflorum); and two management systems: desiccation by herbicide spraying and mechanical mowing, performed each autumn prior to cover crop resowing. The experiment had a completely randomized block design, with three replications. Soil acidity and nutrient contents were little influenced by the plant cover. In comparison with the mowed management, herbicide application increased exchangeable Ca and Mg, extracted P, and organic C levels in the soil. The grape yield in the seasons 2004 and 2006 was low in view to the cultivar potential, probably affect by climatic limitations, but was higher when black oat was used as plant cover instead of the mixture of plant covers.

Tempo de cocção de grãos de feijão em função do tipo d'água

O feijao constitui-se em uma importante fonte de proteina e minerais, mas apresenta atualmente baixo consumo devido ao longo tempo requerido para hidratacao e coccao, a qual aumenta a digestibilidade. Objetivou-se, na pesquisa, estudar o efeito do tipo de agua sobre o tempo de coccao em graos de feijao, em agua ultrapura, destilada, torneira e mineral durante o processo de coccao. Os graos da cultivar BRS-Valente foram hidratados por 21 horas em agua ultra pura, e em intervalos de uma hora procedeu-se a coccao em agua destilada e da torneira ate o ultimo tempo de hidratacao. Apenas no tempo de 6 horas de hidratacao procedeu-se a coccao nas aguas ultrapura, destilada, torneira e mineral. O aumento no tempo de hidratacao favoreceu o menor tempo de coccao, mas essa alta correlacao (-0,9), foi explicada principalmente pela queda acentuada no tempo de coccao, nas duas primeiras horas de hidratacao. Assim, a correlacao geral nao explicou o real comportamento dos resultados obtidos, mas sim a analise conjunta atraves da regressao linear segmentada. Conclui-se que o rapido tempo de hidratacao foi um indicativo do menor tempo de coccao para a cultivar BRS-Valente, desde que o grao apresentasse um porcentual de 69% de hidratacao, no tempo de 2 horas de hidratacao. O uso da agua ultrapura e destilada durante o processo de coccao proporcionou um nivel normal de resistencia a coccao (23 e 30 minutos), a agua da torneira diferiu das demais e causou um nivel resistente a coccao (±37 minutos), enquanto que na agua mineral o tempo de coccao foi muito elevado (>300 minutos).

Teores de Cu e Zn em perfis de solos de diferentes litologias em Santa Catarina

Heavy metals occur in the soil through the weathering of rocks rich in these elements. The objective of this study was to evaluate the contents of Cu and Zn in 58 modal profiles of the major soil types of the State of Santa Catarina, collected in natural soils without anthropogenic interference, and derived from different lithologies. One hundred and eleven soil samples were used from the A and B horizons. The Cu and Zn elements were extracted with Aqua Regia method and quantified by atomic absorption. For the analysis of the results, the data was categorized using as variables the concentrations of Cu and Zn, and the effect of genetic horizon, profile, and rock material on the distribution of these metals using univariate techniques was evaluated. The sampled soils for this study are mostly derived from igneous rocks, which reflects the significant amount of soil derived from these materials in the state. The results indicate that the concentrations of Cu and Zn in South Brazilian soils are related to the geochemical composition of the rock material. So, these elements can be used to indicate the influence of different lithologies and the baseline concentration to environmental monitoring.

Teores de arsênio e cádmio em solos do bioma cerrado

O conhecimento do teor natural de As e Cd em solos e importante para monitorar o risco de possivel entrada desses elementos na cadeia alimentar por fontes antropogenicas. Neste contexto, o objetivo deste trabalho foi determinar o teor natural de As e Cd em solos representativos do bioma Cerrado. Foram coletados solos de tres sub-regioes: G (leste de Goias), T (Triângulo Mineiro) e N (nordeste de MG). Para determinar os teores de As e Cd, as amostras de solo foram submetidas a digestao em forno de micro-ondas, protocolo USEPA 3051A, determinacao em espectrometria de absorcao atomica com atomizacao eletro termica. Os teores medios de As decresceram na seguinte ordem: sub-regiao G (3,29 mg kg-1) > sub-regiao T (2,18 mg kg-1) > sub-regiao N (0,62 mg kg-1). Para Cd, os teores nos solos das sub-regioes G (2,45 µg kg-1) e T (1,88 µg kg-1) foram iguais e superiores aos da N (1,16 µg kg-1). Os maiores teores de As e Cd foram encontrados na sub-regiao G em perfis de Plintossolo e Cambissolo, enquanto os menores teores foram encontrados em perfis de Neossolo Quartzarenico.

Adaptação metodológica no cálculo de cargas contaminantes de fósforo em bacias hidrográficas gaúchas

The excess of phosphorus in the environment can cause several negative impacts, especially with regard to water quality. Hence adequate methodologies are needed for assessing this risk at the watershed scale, emphasizing that the non-point agricultural sources impose greater estimate difficulties. The objective of this work was to propose an adapted methodology to quantify the dissolved and total reactive phosphorus movement in agricultural areas, based on the influence of agricultural crops (arboreous and herbaceous size), native pasture and its management in the State of Rio Grande do Sul (Southern Brazil). The methodology used was the study of reactive phosphorus release in plots covered by different crops and its relation to the methodology of calculation of maximum daily loads, currently accepted by the state environmental agencies for the environmental licensing of potentially polluting activities. The results show that the calculation of load of phosphorus contaminant currently in use, may be underestimating the Brazilian conditions, especially in Rio Grande do Sul, and that the new methodology allows one to include temporal variation as an element in the process of analysis, turning the licensing analysis into a dynamic and punctual process.