Resumo

TORRES, Pedro L; AULAR, Jesús; RENGEL, Marcos  e  MONTANO, José. Nutritional diagnosis of orange orchards in Yaracuy State by using the modified DRIS (DRIS-M). Bioagro [online]. 2010, vol.22, n.2, pp.127-134. ISSN 1316-3361.

The fertilization of orange trees in Venezuela has been accomplished mainly by empirical forms or based in soil analysis. However, these procedures do not take into account all factors that affect nutrients absorption, and originate nutritional imbalances that may impair yield and quality of the fruits. In this research, the nutritional status of orange tree orchards located in the four main citrus zones of Yaracuy State (Aroa, Durute, Nirgua y Yumare) by analysis and DRIS-M diagnostic of 192 foliar samples, and later comparison with soil analysis. It was found that the main nutritional limitation is the phosphorus deficiency, followed by nitrogen excess, zinc deficiency, and iron excess. Potassium, magnesium, calcium and copper were generally in suitable proportions. Deficiencies of copper and manganese were found in Aroa, and only manganese in Nirgua. Some differences among the nutritional diagnoses of the four studied zones were detected. Possible causes of this diagnosis are discussed in the paper.

Palavras-chave : Citrus sinensis; orange tree; fertilization; nutritional balance.