Leaf analysis and fertilizer response
An apple orchard in the Booneville area of Mendocino County was shown, by leaf analyses, to be low in phosphorus and potassium. Test plots were established in the orchard in 1952, and fertilized with nitrogen, potassium, and phosphorus. In 1956 potassium sulfate alone was applied. The amounts of phosphorus and potassium were greater than ordinarily used by growers.