Influence of 12 Ground Cover Systems on Young ‘Smoothee Golden Delicious’ Apple Trees: II. Nutrition

Abstract

Two-year-old ‘Smoothee Golden Delicious’ apples ( Malus domestica Borkh.) on seedling rootstock were planted into cultivated soil in Spring 1981, and 12 ground cover systems were then established. Apple leaves, twigs from pruning cuts, soil samples, and ground cover clippings were analyzed for nutrient content in 1983 and 1984. Leaf N content had the highest positive correlation with tree growth. Leaf P and K contents were negatively correlated with leaf N and tree growth. Twig N, P, K, Mg, Ca, and Zn contents were positively correlated with leaf N content and tree growth. Soil nitrate content was positively correlated with tree growth and leaf N content. Results implicate N competition as a major factor of interaction between apple trees and grass and broadleaf ground covers.