Spatial variability of phoma spot and nutritional aspects of coffee plants and incidence of brown eye spot in coffee quality. / Variabilidade espacial da mancha de phoma relacionada à nutriÃÃo do cafeeiro e incidÃncia da cercosporiose na qualidade do cafÃ.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The present work aimed to apply geostatistic to evaluate the spatial and temporal variability of coffee phoma spot intensity and nutrition under conventional and organic cropping systems, verify the relationship between the nitrogen/potassium (N/K) ration and the phoma spot intensity and coffee seedlings nutritional aspects, grown under nutrient solution, evaluate the chemical and physical properties of coffee after mixing different proportions of coffee beans with and without brown eye spot symptoms. In the first evaluation period, August/2007 to Febuary/2008, the geostatistic modeling revealed spatial variability in coffee phoma spot intensity in the conventional cropping system and best adjusted to the exponential model, whereas the organic cropping system was best described by the pure pepite one. There was a significative correlation between the area under the coffee phoma spot severity progress curve (AUSPC) and N (positive) and also between AUSPC and Ca and Mg (negative). In the second period of evaluation, Febuary to August /2008, there was no spatial dependence between the disease intensity and the distance between the sampled points, the data best adjusted to the EPP model. In both evaluation periods was observed a higher intensity of phoma spot severity in the conventional system compared to the organic one. In the study of the relationship N/K, no significative interaction was observed between N and K for the disease intensity, but with the nutrient content increase in the nutrient solution, for N a linear increase and for K a squared reduction in AUIPC and AUSPC were observed. Regarding the influence of brown eye spot in the coffee quality, there were changes in its chemical and physical composition. With the increase in the proportion of diseased berries there was a linear increase in the polyphenol content, lixiviated potassiun and electrical conductivity and reduction of total sugars, soluble solids and pH. For the physical property one observes reduction in the quantity of berries retained in the larger opening sieves and an increase in the smaller opening ones.

ASSUNTO(S)

phoma sp. geoestatÃstica cercospora cofeeicola quality fitopatologia qualidade geostatistic phoma sp. cercospora cofeeicola

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