Search Results

You are looking at 1 - 6 of 6 items for :

  • Author or Editor: S. B. Boswell x
  • Journal of the American Society for Horticultural Science x
Clear All Modify Search

Abstract

Painting of inhibitors on pruning cuts reduced growth only in the area proximal to treatment in Eucalyptus globulus Labill. Sprays of 0.2 to 0.3% 1-propylphosphonic acid (NIA 10656) or injection of 8 ml of 10% tech grade NIA 10656 gave shoot growth reduction for 1 year. Ethyl hydrogen 1-propylphosphonic acid (EHPP, NIA 10637) showed responses similar to NIA 10656. Naphthaleneacetic acid (NAA), EHPP, NIA 10656 and amonium ethyl carbamoylphosphonate (Krenite) all showed certain growth regulator responses when painted on pruning cuts. Inhibitors applied in an asphalt carrier to cuts were more effective than similar applications in a water carrier. Application of 6, hydroxy-3-(2H) pyridacinone (MH), trifluromethyl sulfonamido-p-acetotoluidide (Sustar), NAA and EHPP combination, or methyl 2-chloro-9-hydroxyfluorene-9-carboxylate (chlorfluernol methyl ester, principal active ingredient in Maintain CF 125) were tested as trunk bark bands for reduction in terminal shoot growth. The Maintain CF 125 product diluted with an equal amount of diesel oil and applied in a band equal to the trunk diameter of E. camaldulensis Denhardt effected a reduction in terminal growth 11 months after banding. Maintain CF 125 applied at full product strength (12.5%) or diluted equally with water and the other inhibitors tested did not cause growth reduction.

Open Access

Abstract

Trees of old-line ‘Atwood’ navel orange [Citrus sinensis (L.) Osbeck] on Rubidoux trifoliate orange [Poncirus trifoliata (L.) Raf.] rootstock were planted in 1970 at 6 different spacings in 5 replications to determine effects of tree spacing on fruit quality, tree growth, yield, air temperature, light penetration, and production costs. Growth rate was measured by trunk circumference and tree height. Trunk circumference increased as spacing increased. Closely spaced trees were 0.7 m higher than widely spaced trees after 9 years. Fruit quality analyses showed no differences until the trees began to crowd. Fruit colored faster in 1980 on the widely spaced trees than on closely spaced trees. Fruit from trees spaced 5.5 × 5.5 m reached legal maturity (8:1, solids:acid ratio) 12 days ahead of fruit from trees spaced 2.7 × 4.6 m.

Open Access

Abstract

The effect of tree spacing on the root distribution of 9-year old ‘Washington’ navel orange trees on ‘Troyer’ citrange rootstock was studied. Spacings ranged from 9 ft x 15 ft to 22 ft x 22 ft. Roots were washed from soil cores (3-ft deep, 4-inch diam) taken at 2-ft intervals along 2 transects, 1 across the row and 1 along the row and beneath an irrigation furrow. The distribution of both small roots (1.5 mm in diam or smaller) and large roots was affected by tree spacing and by location of the irrigation furrow. At close springs, many soil cores contained about 4 g dry wt of small roots, suggesting that the soil contained as many feeder roots as possible under those conditions. Wider spacings had fewer roots per core. Evidence suggests that considerable overlapping of root systems occurred at close spacings but not at the wider spacings. It is likely that root competition will limit yield during the next decade at the closer spacings, whereas considerable room for root growth exists at wide spacings.

Open Access

Abstract

In 1961, trees of Frost Nucellar ‘Washington’ navel orange on Troyer Citrange rootstock were planted at eleven different spacings to determine the effect of tree spacing on growth, production, and fruit quality. Growth rate as measured by trunk circumference was proportional to decreasing tree density or increased spacing. The wider the spacing, the greater was the trunk circumference and the fruit-bearing capacity of the tree. Shading of skirt foliage, as closely planted trees began to crowd, caused the skirts to die and decreased production. Pruning to keep these trees from crowding reduced yield in proportion to the amount of foliage removed. Removal of alternate trees in the two most densely planted spacings, 9 ft. × 11 ft. and 11 ft. × 11 ft., reduced competition and allowed more light to reach the remaining trees. Skirt foliage regrew and yield per-tree and per-acre increased.

Fruit colored faster and was larger on the widely spaced trees, where less shading had occurred, than on closely spaced trees. Fruit quality analysis showed no difference in percent of juice, soluble solids, acid, or rag, or in peel and rind thickness.

The closest spacings, 9 ft. × 11 ft., 9 ft. × 15 ft. and 11 ft. × 11 ft., operated at a net loss for the first five years of production. Although per tree production was highest on the widest spacing, 22 ft. × 22 ft., net returns per acre on this spacing are still low because of the number of trees per acre. The 11 ft. × 22 ft. spacing with 180 trees per acre had the largest net income per acre.

Open Access

Abstract

High density planting of tree crops has the potential of increasing yield and income during the early years of an orchard’s life. Eleven different planting densities of citrus were studied over a 10-year period to determine the effect of tree spacing on yield, tree growth, root distribution, nutrition, and economic factors involved. Extremely close plantings soon crowded to the point where they were unmanageable and tree removal became necessary. Pruning was needed to maintain a workable orchard in more moderatley spaced plots.

Open Access

Abstract

‘Prior Lisbon’ lemon trees were treated with increasing rates of N fertilizer up to 6 lb. N per tree per year. Likewise, ‘Monroe Lisbon’ lemon trees were treated with up to 4 lb. N per tree per year. Also, for the Trior Lisbon/one treatment was 6 urea foliage sprays per year which supplied about 2 lb. N per tree per year. For the Trior Lisbon’ there was a tendency for yields to increase with increasing N rates with the high rate yielding significantly more than the low rate. Yield was highly correlated with leaf N with maximum yield occurring at about 2.2% leaf N. Urea foliage sprays maintained leaf N and maximum yield. Fruit quality was not adversely affected by increasing N. As with Prior ‘Lisbon’, ‘Monroe Lisbon’ yields increased with increasing N but the maximum yield occurred at about 2.5% leaf N. Yields from single N applications were not different from split N applications.

Open Access