Macadamia nut size and maturity influenced by lime and nitrogen applications

Abstract

A long-term study of the effects of lime and nitrogen on a young macadamia orchard included acidifying sulfate of ammonia treatments to separate pH and Ca effects of lime applications. Lime, per se, had no influence on yield, quality, or trunk girth growth. Annual nitrogen applications (with or without neutralising applications of lime), however, consistently depressed the size of nuts and kernels and the percentage of first grade kernels, but had no effect on yield or other quality characteristics. More nuts developed with N treatments but failed to fill effectively.