Georgia pecan producers since 2010 in anticipation of maintaining these densities through hedge pruning ( Wells, 2014 ). As pecan trees grow in an orchard, their tree canopies encroach on one another, causing excessive shading, which has been shown to
Bruce W. Wood and Deane Stahmann
An ever increasing cost:price squeeze on the profitability of pecan (Carya illinoinensis) farming is driving a search for alternate husbandry approaches. `Wichita' and `Western' trees maintained at relatively high tree population density, by mechanized hedge pruning and topping, produced greater nut yield than an orchard treatment in which tree population density was reduced by tree thinning (144% for `Wichita' and 113% for `Western Schley'). Evaluation of three different hedge pruning strategies, over a 20-year period, identified a discrete canopy hedge pruning and topping strategy using a 2-year cycle, as being superior to that of a discrete canopy hedge pruning and topping strategy using an 8-year cycle, but not as good as a continuous canopy hedge pruning and topping strategy using a 1-year cycle. An evaluation of 21 commercial cultivars indicated that nut yields of essentially all cultivars can be relatively high if properly hedge pruned [annual in-shell nut yields of 2200 to 3626 lb/acre (2465.8 to 4064.1 kg·ha-1), depending on cultivar]. Comparative alternate bearing intensity and nut quality characteristics are reported for 21 cultivars. These evaluations indicate that pecan orchards can be highly productive, with substantially reduced alternate bearing, when managed via a hedge-row-like pruning strategy giving narrow canopies [3403 lb/acre (3814.2 kg·ha-1) for `Wichita' and 3472 lb/acre (3891.5 kg·ha-1) for `Western Schley']. North-south-oriented (N-S) hedgerows produced higher yields that did east-west (E-W) hedgerows (yield for N-S `Wichita' was 158% that of E-W trees and N-S `Western Schley' was 174% that of E-W trees).
These data indicate that mechanized hedge pruning and topping offers an attractive alternative to the conventional husbandry paradigm.
Bruce W. Wood
stress”, typically increases alternate bearing intensity ( I ; Pearce and Dobersek-Urbanc, 1967 ), which is perhaps the economically most important biological problem faced by commercial pecan enterprises. Timely use of mechanized hedge-type pruning as a
Bernadine C. Strik and Gil Buller
been shown to increase yield compared with untipped canes, hard-tipping would cut the cane back to older growth and potentially more mature buds. It would likely be easier to mechanize hard hedging in commercial production systems. Our hypotheses were 1
Lisa McFadyen, David Robertson, Margaret Sedgley, Paul Kristiansen, and Trevor Olesen
). Regularly hedging the sides of small trees maintains light and ventilation to the lower canopy and orchard floor between tree rows and, for nine-year-old trees, caused less yield loss than tree removal ( McFadyen et al., 2004 ). However, as tree height
E. W. Neuendorff and K. D. Patten
A late spring frost, -2°C on 10 Mar 1989, destroyed all blossoms on `Delite' rabbiteye blueberries. To determine the effect of hedging as a rejuvenation method, six-year-old `Delite' plants were pruned on 26 April 1989. All branches were removed at 46 cm from ground level. Unpruned control plants were approximately 184 cm tall. On 21 Mar 1990 a frost of -2°C occurred. Two days later bud damage was assessed on three wood types: spring-old (SO), spring growth on old, weak wood; spring-new (SN), spring growth on vigorous 1-year-old shoots; and fall (F), postharvest late summer/fall growth. Buds were identified as to their stage of development. Buds formed on both types of spring wood were further developed than those on fall wood. As flower stage advanced frost damage increased. Blossoms on fall growth were most frost tolerant and SN was more hardy than SO. Subsequent yields will be determined and reported.
David C. Ferree
In 1981, four apple cultivars were established as a low trellis hedgerow on M.9 or free-standing central leaders on M.7 at the recommended or half the recommended spacing with the close planted trees either root pruned annually at bloom or hedged in August. Planting at half the spacing and annual summer hedging 2 sides decreased TCA 25% and canopy volume 51% with no effect on shoot growth, while annual root pruning decreased TCA 34%, canopy volume 50% and shoot length 25%. Planting at half spacing and either hedging or root pruning reduced yields per tree. Efficiency as measured by yield TCA was decreased by hedging and as measured by yield/m3 canopy volume was increased by both treatments with hedging having the greatest effect. The cumulative yield/ha was increased by both hedging and root pruning with no difference between them. Fruit size was decreased by close planting and root pruning caused a greater decrease than hedging. Close planting increased the number of spurs and shoots and LAI per unit volume of canopy with no difference between hedging or root pruning. `Empire' outproduced `Smoothee' and `Delicious' on the trellis and `Lawspur' had higher yields than any other cultivar in the central leader.
Osamu Kawabata and Richard A. Criley
An aqueous solution of dikegulac-sodium at 0, 2000, 4000, 6000, or 8000 mg a.i./liter was sprayed on a mature Murraya paniculata hedge as the first leaves expanded on newly developing lateral shoots after trimming. The lateral shoots from each 0.09-m2 hedge surface elongated less and the coefficient of variation (cv) decreased as the growth regulator concentration increased. Application of dikegulac-sodium at 4000 mg a.i./liter to the most distal leaf on topped, single-leader seedlings inhibited the elongation of distal shoots while it enhanced proximal shoot growth. Dikegulac-sodium spray between 4000 and 6000 mg a.i./liter to the hedge decreased apical dominance among lateral shoots and enhanced uniform regrowth without causing visible damages. The cv reduction was attributed to the growth regulator-induced weakening of apical dominance. Chemical name used: sodium salt of 2,3:4,6-bis-O-(1-methylethylidene)-α-l-xylo-2-hexulofuranosonic acid (dikegulac-sodium).
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.
D.B. Rowe, F.A. Blazich, D.M. Pharr, and F.C. Wise
Containerized, 2.5-year-old, hedged stock plants of four, full-sib families of loblolly pine (Pinus taeda L.) were fertilized daily with a complete nutrient solution containing 10, 25, 40, 55, or 70 ppm N, which resulted in a range of stock plant soluble carbohydrate (SCHO) and tissue N levels. SCHOs included myo-inositol, glucose, fructose, sucrose, and raffinose. Nitrogen concentrations and SCHO: N ratios ranged from 1.23% to 2.24% and 16:1 to 29:1, respectively. Softwood cuttings were taken in May and July 1995 and placed under intermittent mist. May cuttings rooted at significantly greater percentages than July cuttings (60% vs. 34%). Averaged over all N treatments, the best rooting family (56%) contained the highest tissue concentration of SCHOs (465 mg·g–1 dry weight) and had the highest SCHO: N ratio (26:1), whereas, the poorest rooting family (39%), exhibited the lowest level of SCHOs (357 mg·g–1 dry weight) and the lowest SCHO: N ratio (21:1). Rooting exhibited a quadratic response in regards to N fertilization levels and tissue SCHO concentrations. For both rooting trials, maximum rooting (83%) was noted for May cuttings taken from stock plants of one family fertilized with 40 ppm N, which corresponded to a tissue N concentration of 1.95% and a SCHO: N ratio of 22:1.