Effect of soil treatment, rootstock and tree density on the establishment phase of apple high density plantings on a replant site

A high density systems trial on a replant soil was planted in 1998 on the HortResearch Crosses Road Orchard, Havelock North, New Zealand. Pacific Beauty(TM) on three rootstocks (M.26, M.9 and Mark) each planted at three densities (1428, 1587 and 1904 trees/ha for M.26; 1587, 1904 and 2198 trees/ha for M.9 and Mark) were planted in a split plot design using soil treatment as the main effect. The soil was either nonfumigated or fumigated with 70% Methyl Bromide and 30% Chloropicrin. One year after planting the interaction between fumigation and rootstock was the major determinant of tree growth. All rootstocks had greater vigour in fumigated soil. In fumigated soil, Mark and M.26 had similar total shoot length and percent growth increments, which were significantly greater than M.9. However, in nonfumigated soil, Mark had greater shoot length, shoot number and a 24% greater growth increment when compared with M.26. Tree density did not have a significant effect in the first year after planting.