ISHS Acta Horticulturae 494: II International Symposium on Chestnut
SOIL FACTORS, FARMER'S PRACTICES AND CHESTNUT INK DISEASE: SOME INTERACTIONS |
| Authors: | E. Portela, J. Aranha, A. Martins, A.L. Pires |
| Keywords: | Phytophthora, Castanea sativa, grove management |
| Abstract:
The widespread occurrence of ink disease induced by Phytophthora cinnamomi Rands causes important losses in chestnut groves and limits the establishment of new groves in northern Portugal. The existence of both healthy and severely affected chestnut groves in areas where environmental conditions are apparently the same, suggests that farmer's practices, soil factors or their interaction contribute to the incidence of disease. Therefore, eight pairs of adjacent chestnut groves, some severely affected with ink disease and some slightly affected or with no disease, were surveyed in order to determine site characteristics, soil properties and cropping practices. The leaves of chestnuts with different degrees of disease were collected and analyzed for macronutrients. To investigate the relationship between the severity of ink disease and site characteristics, soil properties and cropping practices, data from chestnut groves exhibiting different degrees of infection were submitted to principal components analysis (PCA). The relationship between the severity of ink disease and concentrations of plant nutrients were also submitted to PCA. The importance of soil fertility parameters, soil organic matter and effective soil depth in improving the health conditions of chestnuts was underscored, while radiation, frequency of tillage and imbalanced mineral fertilization contributed to the severity of ink disease. The relative position of the chestnut grove, on the upper or the lower slope affects the hydrological conditions and rooting depth of chestnuts. The results showed that it was not possible to single out one factor as being responsible for the development of chestnut ink disease. Factors that debilitate the trees and reduce their capacity to recover from damage, such as restrictions to root expansion, poor soil fertility, low aeration and soil disturbance by tillage are associated with the occurrence of ink disease. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
