BIOMASS AND NUTRIENT ACCUMULATION BY APPLE TREES GROWN IN A COMMERCIAL NURSERY

Two trials to determine the influence of various management practices on the performance of apple (Malus × domestica) trees grown in the Los Olmos commercial nursery, located in San Fernando, VI Region, Chile were conducted. The first trial was conducted during the 1997-98 growing season and examined the effect of N fertilization rate (0 to 400 kg ha^-1 N as urea) on biomass and nutrient accumulation by ‘Royal Gala’, ‘Granny Smith’ and ‘Red Chief Delicious’ trees grafted on 1- and 2-year-old MM.106 rootstocks. Biomass accumulation by the ‘Royal Gala’ and ‘Red Chief’ trees was unaffected by N rate, while the maximum growth of ‘Granny Smith’ trees occurred at 100 kg N ha^-1. The amounts of N present in apple trees exceeded fertilizer N rates in the 0, 100 and 200 kg N ha^-1 application treatments. About half of the N was partitioned to the leaves, with the shoots and roots each containing about 25%. The second trial was conducted during the 2003-04 growing season and examined the effect of rootstock and scion combination on tree biomass and nutrient accumulation (T1: 1-year-old M.9 rootstock with no grafted scion; 2) T2: 1-year-old ‘Galaxy’ scion grafted on 1-year-old M.9 rootstock; 3) T3: 1-year-old ‘Galaxy’ scion grafted on 2-year-old M.9 rootstock). Maximum accumulation of fresh matter was achieved in T3, with around 450 g plant-1 vs. 254 g plant^-1 in T1. Nutrient extraction varied from 90 kg N ha^-1 in T1, to 138 kg N ha-1 for T3.