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  • Author or Editor: T. W. Young x
  • Journal of the American Society for Horticultural Science x
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Abstract

Leaves were collected in 1974 and 1975 from mature ‘Tonnage’, ‘Lula’, ‘Taylor’, and ‘Booth 8’ avocado trees (Persea americana Mill.) on sand, muck, and calcareous rock soils and analyzed for N, P, K, Ca, Mg, Mn, Cu, Zn, and Fe. Significant differences in levels of all 9 elements in ‘Tonnage’ leaves occurred among the 3 soil types. Crop size, fertilization, soil pH, soil Ca level, and exchange capacity of the soil appeared to be important factors in the variations. Differences in concentration of N and P were not significant among the 4 cultivars but were significant for the other elements.

Open Access
Authors: and

Abstract

As leaves of ‘Tonnage’ avocado (Persea americana Mill.) increased in age, N, P, and K contents decreased, while Ca, Mg, Mn, Cu, Zn, and Fe contents were higher. A comparison of leaves from 1st and 2nd flushes showed similar trends reflected in leaf age. The basal leaf was lower in P but higher in Ca, Mg, and Cu when compared with the terminal leaf of the same twig. Only N and Cu contents were different when leaves from fruiting and nonfruiting twigs were compared. Practical application of the data in sampling avocado leaves is discussed.

Open Access
Authors: and

Abstract

Fertilization of field grown roses, R. hybrida cv. Christian Dior, in south Florida with fertilizer packets and tablets was compared with a proven plastic mulch method of reducing fertilizer losses. Flower yields for the 3 methods were similar during the first 9 months of the study. In the second year, comparatively low yields were obtained with tablets, and the highest yields with the plastic mulch. The packets gave intermediate results, with 5 packets providing acceptable yields. Twenty-one months after placement, the tablets contained 56, 56, and less than 0.1% of their original N, P, and K, respectively. Nitrogen release at this time appeared comparatively slow. Considerable variation in nutrient content existed among packets 21 months after placement, with an average of 17, 33, and 38% of the original N, P, and K, respectively, being found. The packets still appeared to be releasing fertilizer at that time.

Open Access
Authors: and

Abstract

As mango leaves increased in age, lower P and K contents were found, while Ca content was higher. The basal leaf was lower in N and Ca but higher in P and K contents when compared with the terminal leaf of the same shoots. Only small differences were observed when leaves were compared from fruiting and nonfruiting shoots. The practical application of data in sampling mango leaves is discussed.

Open Access

Abstract

Yields and quality were compared on young bearing ‘Bearss’ lemon (Citrus limon L.) trees grown with 3 rates of N and K and 2 levels of soil moisture over a 4-year period. Increased rates of N application increased fruit production, incidence of fruit with scab, and green fruit; and decreased acid content of juice. Potassium applications increased the acid content of juice. Irrigation increased fruit size and decreased the number of green fruit after curing. A leaf N content of 2.2 to 2.6% is suggested for optimum fruit production for ‘Bearss’ lemon under Florida conditions.

Open Access

Abstract

‘Christian Dior’ and ‘Happiness’ roses on Rosa fortuniana stock, fertilized with 3 rates each of N, P, and K factorially combined, were grown for 3 years at Ft. Pierce, Florida. All fertilizer was applied at the beginning of the experiment under plastic mulch just before the bushes were planted. About 2300 lb./A of N on ‘Christian Dior’ and 2100 lb. on ‘Happiness’ produced the greatest number of flowers. Leaf N at 18 months was also maximized by 2100 lb. N. Nitrogen levels maximizing stem lengths were slightly lower. The independent effects of P were minor and low levels best, perhaps because residual soil P at start of the study was adequate. Flower production decreased with K fertilization beyond low rates, whereas stem lengths increased to a max at about 1700 lb./A. At times, various nutrient interactions were noted. ‘Christian Dior’ consistently yielded more flowers than ‘Happiness’. With minor exceptions, ‘Happiness’ had longer stems.

Open Access

Abstract

Results are presented for performance of pecan [Carya illinoinensis (Wangenh.) C. Koch] clones at six established National Pecan Advanced Clone Testing System (NPACTS) sites for 16 nut quality factors from 1980 through 1985. Total nut weight and percent kernel were significantly greater at Tulare, Calif. than at any other location, with ≈80% of the clones averaging 6.5 g/nut or more and ≈90% averaging at least 54.5% kernel. Nut weight was smallest at El Paso, Texas. Daily mean temperatures during nut expansion may be a major factor determining nut weight response. Low nut density was characteristic of more clones at Baton Rouge, La. than at any other location. Kernel color was lightest at El Paso and darkest at Baton Rouge, with darker color appearing to be related to high field moisture conditions before harvest. Nut weight was not related to kernel percentage, color, or percent kernel covered with fuzz (packing material); thus, large nuts are not necessarily of lower quality and can be selected in an effective breeding program. Amount of nut “packing material” retained in the sutures of kernel halves after shelling was generally not related to other traits, except that material retained in ventral grooves increased with nut and kernel weight. Depth and width of dorsal grooves were not related to retention of packing material and can be disregarded in future pecan nut evaluation systems. Many other expected character relationships were verified and the overall NPACTS nut evaluation system will be revised based on these results.

Open Access