`Norman' peach [Prunus persica (L.) Batsch] trees were trained to the central-leader or open-vase form and were planted at high (740 trees/ha), or low (370 trees/ha) density. A third density treatment was a HIGH → LOW density, where alternate trees in high-density plots were removed after 6 years to produce a low-density treatment. From 3 to 5 years after planting, trunk cross-sectional areas (TCA) increased most for low-density trees. After 9 years, TCA was greatest for low-density and least for high-density trees. Because of differences in tree training, central-leader trees were taller than open-vase trees and tree spread was greater for low-density than for high-density trees. Annual yield per hectare was 15% to 40% greater for high-density treatments than for low-density treatments, but tree form had little influence on yield. Average fruit weight tended to be greater for low-density than for high-density treatments, but cumulative marketable yield was greatest for high-density and lowest for HIGH → LOW treatments. Income minus costs for 9 years was nearly $4200/ha higher, and net present value was about $2200/ha higher, for open-vase than for central-leader trees (P = 0.08). Cumulative net present value for the 9 years was about $2660/ha higher for high-than for low-density trees (P = 0.36).
Richard P. Marini and Donald S. Sowers
Richard P. Marini, Donald S. Sowers, and Michele Choma Marini
`Sweet Sue' peach (Prunus persica L. Batsch) trees were subjected to a factorial arrangement of treatments. At planting, trees were headed at 10 or 70 cm above the bud union and trees were trained to an open-vase or central-leader form. For the first 4 years, high-headed trees were larger than low-headed trees. After 7 years, open-vase trees had larger trunk cross-sectional area, tree spread, and canopy volume than central-leader trees. Open-vase trees had higher yield and crop value per tree, but lower yield and crop value per unit of land area or unit of canopy volume than central-leader trees. Crop density and yield efficiency were similar for all treatments.