Effects of Rate and Timing of Fertilizer Application on Yield of Macadamia (Macadamia integrifolia Maiden & Betche) in Japan

We carried out experiments to determine the optimal rate and timing of fertilizer application to macadamia (Macadamia integrifolia Maiden & Betche) in Wakayama Prefecture, Japan. To determine the optimal rates of fertilizer application, fertilizer was applied once a year in a macadamia orchard lying on gray lowland soils after converts in from paddy fields. The fertilizer was applied in April, at a rate of 150, 300 or 450 kg N/ ha. The maximum yield was obtained with a fertilizer application rate of 150 kg N/ ha/ year. The timing of fertilizer application was studied in a macadamia orchard lying on brown earth in the upland soils of Susami, southern Wakayama Prefecture. Fertilizer (300 kg N/ ha) was applied in three different ways: total amount applied in spring (April); half-amount applied in spring (April) and half-amount applied in autumn (October); or total amount applied in autumn (October). The highest yield was obtained when the total amount was applied in spring (April).