NUTRITIONAL DISORDERS OF DECIDUOUS FRUITS IN CHINA: DIAGNOSIS AND CONTROL

Visual symptoms are useful in identifying nutritional disorders. However, in order to diagnose the imbalance responsible for the occurrence of a specific symptom, analysis of the nutrient content of one or more parts of the plant is necessary. Nutritional ranges of normal, below normal, deficient, excess and toxic in the leaves for some major fruits in China have been established as the basis for diagnosis of the nutritional status of the plant. Leaf analysis should be supplemented by soil analysis. But in many cases, no consistent correlation was found between these two. Attempt is being made to screen species and ecotypes of Malus which show high ability in the uptake and utilization of nutrient elements. Preliminary results of inoculating with mycorrhizal fungi to enhance the uptake of certain nutrient elements were promising.