Diagnosis of the nutritional status of pear tree Rocha based on leaf-analysis: compositional nutrient diagnosis methodology [Portugal]
2002
Calouro, F. | Duarte, L. | Jordao, P.
Leaf mineral composition, expressed as concentrations or relative (ratio) values on a dry matter basis (100-105 C), have been used as the basic numerical information for diagnosing the nutritional status of cultivated plants. In 1992, Parent and Dafir presented a new diagnosing methodology - the Compositional Nutrient Diagnosis (CND) - based on the principles of statistical analysis developed by Aitchison (1982) for analysing compositional data. These data show a structure of dependence among them, summing up to one or 100%. The main purpose of this study was to establish CND norms for macro and micronutrients to be used as reference values to diagnose the nutritional status of pear tree cultivar Rocha and to make fertilizer recommendations. The present results were obtained from a data bank of the cultivar that included data collected at eight orchards, located in the Portuguese region of the Oeste, during three consecutive years. For this purpose, 15 trees were randomly selected in each orchard, and individual leaf samples were taken from the middle portion of the shoot of the growing season, 100-110 days after full bloom. Total yield from each tree was recorded as well as its distribution according to the fruit size. Leaf analysis was performed using chemical methods in use at Laboratorio Quimico Agricola Rebelo da Silva. CND norms were established using data from those trees showing yields with fruit size within the range ]55 - 75] mm equal or higher than the third quartile of all collected data. CND norms are presented as well as the performed study to establish the nutritional balance of the corresponding trees
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