THIRTY YEARS OF DIAGNOSING NUTRITIONAL STATUS OF DECIDUOUS ORCHARDS AND VINEYARDS BY LEAF ANALYSES IN ONTARIO, CANADA

The Ontario Leaf Analyses Service was established in 1958 for apple, peach and grape by the Ontario Ministry of Agriculture and Food.
Pear and Montmorency cherry were added later.
Growers have widely used the service and have been able to predict the fertilizer requirements of their orchards and vineyards more accurately by leaf analysis than by general recommendations, visual symptoms or soil testing.
Trends in nutrient composition and changes in nutritional problems particularly with apple will be discussed.

Control of nitrogen levels continues to be a challenge.
Excessive nitrogen results in poor quality fruit, fruit disorders, disease, and winter injury.
Potassium deficiency is also common and more serious with excessive nitrogen.
The frequency of magnesium deficiency has increased with increased use of potassium fertilizer.
Boron deficiency occurs more frequently in dry years on sandy soils or with alkaline soil conditions.
Leaf analyses has taken the guess work from orchard fertilization and helped to avoid these problems.

International Symposium on Diagnosis of Nutritional Status of Deciduous Fruit Orchards

R.A. Cline

https://doi.org/10.17660/ActaHortic.1990.274.11