`Norman' peach 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. 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. Fruit size 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 density treatments. After 9 years, cumulative crop value was higher for open-vase than central-leader treatments (P = 0.12), but tree density had less of an effect on crop value (P = 0.21). Cumulative costs were highest for high-density treatments, but were not influenced by tree form. Income minus costs was nearly $4500/ha higher for open-vase than for central-leader trees and net present value was more than $2000/ha higher for high-density than low-density trees (P = 0.20). Open-vase trees were more profitable than central leader trees and should be planted at densities of about 700 trees/ha in the mid-Atlantic region.
Michael W. Smith
affecting productivity. Hinrichs (1961) , working with native pecan tree stands in central Oklahoma, determined that maximum productivity occurred when tree density was 6.9 m 2 ·ha −1 cross-sectional trunk area (30 ft 2 /acre cross-sectional trunk area
T.A. Wheaton, J.D. Whitney, W.S. Castle, R.P. Muraro, H.W. Browning and D.P.H. Tucker
A factorial experiment begun in 1980 included `Hamlin' and `Valencia' sweet-orange scions [Citrus sinensis (L.) Osb.], and Milam lemon (C. jambhiri Lush) and Rusk citrange [C. sinensis × Poncirus trifoliata (L.) Raf.] rootstocks, tree topping heights of 3.7 and 5.5 m, between-row spacings of 4.5 and 6.0 m, and in-row spacings of 2.5 and 4.5 m. The spacing combinations provided tree densities of 370, 494, 667, and 889 trees ha. Yield increased with increasing tree density during the early years of production. For tree ages 9 to 13 years, however, there was no consistent relationship between yield and tree density. Rusk citrange, a rootstock of moderate vigor, produced smaller trees and better yield, fruit quality, and economic returns than Milam lemon, a vigorous rootstock. After filling their allocated space, yield and fruit quality of trees on Milam rootstock declined with increasing tree density at the lower topping height. Cumulative economic returns at year 13 were not related to tree density.
in Georgia during the 2010 and 2012–14 planting seasons. Table 2. Percentage of nursery-grown pecan trees planted to new orchards or interplanted in existing orchards, mean tree density of new orchard plantings, and mean area planted from nurseries in
David R. Walker
Spur and nonspur `Red Delicious' apple trees on M.26, 7, 106, and 111 were planted at different spacings. Yields were recorded for 15 years to assess the effect of early production on the M.26 trees with the later production on the M.106 and M.111 trees. The field data have been used to calculate income and expenses on a hypothetical 16-ha orchard during the 15-year period.
Jack Jordan, E.J. Gregory, D. Smith and I. Benally
A three density-three rootstock test was conducted on three spur-type apple cultivars grown in sandy loam soil. Trees of the three cultivars: `Redspuree' (RS), `Goldspuree' (GS), and `Spuree Rome' (SR) were trained to a central leader system in a 100% grass cover. All cultivars produced best in the high density planting (1344 trees/ha.). Most consistently and significantly affected were the SR. The least productive density, the low density, had 336 trees per ha. while the medium density had 672 trees/ha. Density had a more significant effect on SR culls and a slightly more significant effect on SR fruit soluble solids than it did on these variables of the other cultivars. Density had little effect on fruit firmness of all cultivars. Of these rootstocks: m7a, m26, and mml06, the mml06 rootstock usually produced the greatest yields, especially in the RS and SR cultivars. Results for the GS were more variable than they were for RS and SR with its production on the m7a rootstock occasionally exceeding that of the mml06 rootstock. The m26 rootstock produced the lowest yields. Rootstock had no significant effect on fruit firmness of all cultivars.
Richard P. Marini and Donald S. Sowers
`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).
David C. Ferree and W. Timothy Rhodus
Annual mechanical hedging in August or root pruning at bloom was used to control the growth of four apple (Malus domestica Borkh.) cultivars in two orchard systems planted at half the recommended in-row spacing. Trunk cross-sectional area (TCA) per hectare on the trellis system was 30% higher, a result that correlated (r = 0.80) to a 40% higher cumulative yield per hectare over 10 years compared to the central leader system. Over 10 years, the cumulative yield and TCA per hectare of `Smoothee Golden Delicious', `Empire', and `Redchief Delicious' were higher in the trellis than the central leader system, while these characteristics of `Lawspur Rome Beauty' were not influenced by orchard system. `Lawspur' had the highest TCA per hectare, cumulative yield per hectare, and greatest tendency toward biennial bearing of the four cultivars. Root pruning reduced all tree-size measurements, while hedging did not influence tree height or average shoot length. Yield and yield per TCA were reduced by hedging and root pruning, with the greatest reduction in yield caused by root pruning. Hedging increased cumulative yield per hectare with root-pruned trees intermediate between hedged standard-spaced trees. Trellis trees had a higher density of spurs and shoots and a higher leaf area index than trees on the central leader system. An evaluation of the treatment combinations using net present value analysis indicated that none of the treatments was a profitable investment. Of the top twelve treatments, as evaluated for 10 years, nine were the central leader and three the trellis system, with none of the trellis and only four of the central leader treatments being hedged or root-pruned. Results of this study indicate that orchard intensification is accomplished best by choosing appropriate planting distances and not by attempting to control growth mechanically on trees planted too close for optimum performance.
Ariel Singerman, Marina Burani-Arouca and Stephen H. Futch
production of citrus in Florida in the era of HLB. The estimates include both the costs of materials and the costs associated with their application (i.e., labor). The tree density baseline for our analysis is 358 trees/ha, which is the average tree density
D.M. Glenn, T. Tworkoski, R. Scorza and S.S. Miller
density. The objectives of the study were to evaluate the interactions of pruning strategies, groundcover management, tree densities, and peach architecture combined in eight peach production systems on components of yield and economic value. Materials and