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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.
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.
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.
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.
To promote both learning and horticulture, a 5 year pilot program was implemented with a collaborative effort between the Louisiana State University Horticulture Department and the University Laboratory School. The objective of this program was to develop a hands-on approach to learning which fostered self-discovery and a positive perception of horticulture. First graders were able to experiment in both the greenhouse and in the field with instruction in the classroom. Among the many concepts that the children were Introduced to, they benefitted most from being able to participate and observe the process from seeding to harvesting enabling them to work with the different types of seeds, media, and fertilizers. In the classroom, horticulture was Integrated in every subject of the first grade class. For example, the students learned math by measuring and counting the produce then making charts to report their findings. The result of the program was that the children did in fact obtain a positive perspective of horticulture while developing an awareness of the process of growth and development of horticultural crops. The first grade class received a national award for donating their produce to the local food bank in Baton Rouge.
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.
Abstract
A population of 100 sweet potato seedlings from 7 parent clones was grown for one season in order to evaluate root protein quantity and quality. Protein content of the 100 seedlings ranged from 4.38% to 8.98% with a mean of 6.29%; the 7 parents ranged from 4.96% to 6.53% with a mean of 5.72%. The mean of the seedlings was not significantly different from that of the parents. The 10 seedlings with highest protein (7.40% to 8.98%) were selected for further study of protein quality. Levels of nonprotein nitrogen (NPN) in these high protein selections were not significantly different from those of the parents. The correlation between the percentage of protein and the percentage of NPN was low (r = 0.30). The amino acid pattern in the high protein selections differed significantly from the parents with lower levels of valine, cysteine, methionine, tyrosine, and phenylalanine. Trypsin inhibitor activity (TIA) levels in the selected seedlings did not vary significantly from the parents. TIA and the percentage of protein were not significantly correlated (r = 0.15). The results indicate it is possible to obtain high protein cultivars without increasing the percentages of NPN and TIA. With the exception of valine, the aromatic and sulfur-containing amino acids, the overall protein quality was not changed in the seedlings with increased protein content.