EIGHT YEARS OF OBSERVATIONS ON A PEACH DOUBLE-ROW PLANTED ORCHARD
Tree growth was inversely related to planting density, the differences becoming greater as the trees aged. The closer between-row spacings reduced trunk girth increment more than would have been expected from planting density alone. The trunk cross-sectional area of the free spindles was 40 to 60% less than that of the sprint palmettes and their height was also less. These differences in height were inversely related to tree density and were around 20% in the early years of the experiment. In the later years the double-row trees showed greater height increments, especially in the plots with the narrow inter-row spacing.
Accumulated crop per tree was, in general, inversely related to the number of trees per hectare but the trees in the systems with the wide inter-rows yielded relatively more than those with narrow inter-row spacing.
Crops from the free-spindle trees increased rapidly in the first 3 years up to 20–35 kg/tree and maintained this value up to the end of the period covered in this report (8 years). Trees grown as sprint palmettes reached their plateau level of production (60 kg/tree) after 5 years.
Regardless of variety the accumulated yield over 8 years was 155 tons/ha from the sprint palmettes and was much higher from the double-row systems. At 2 050 trees/ha these yielded 249 tons/ha, at 2 220 trees/ha they yielded 229 tons/ha.
Contrary to expectation, the growth and yield of the trees in the double row plantings were so satisfactory after 8 years that another 2 to 3 years of good crops are now expected.