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- Author or Editor: Timothy K. Broschat x
Queen palms (Syagrus romanzoffiana) were grown in containers of sand to determine the effects of irrigation water salinity and liming rate on cation uptake by the plants. Dolomite was incorporated at rates of 0, 3, or 6 kg/m3. Within each lime rate palms were irrigated with a solution of NaCl and CaCl2 (molar ratio =5Na:1Ca) at conductivities of .25, 1, 2, 4, or 6 dS/m. Plant height and dry weight and leaf Mg were decreased with increasing irrigation water salinity, whereas leaf Ca was increased at higher salinities. Leaf Mn and Zn increased, then decreased as salinity was increased. Leaf Ca and Mg increased with increased lime, but leaf Mn and Cu were decreased by increasing the lime rate. Leaf K increased, then decreased as lime rate was increased.
Queen palms (Syagrus romanzoffiana) were grown in containers of sand to determine the effects of irrigation water salinity and liming rate on cation uptake by the plants. Dolomite was incorporated at rates of 0, 3, or 6 kg/m3. Within each lime rate palms were irrigated with a solution of NaCl and CaCl2 (molar ratio =5Na:1Ca) at conductivities of .25, 1, 2, 4, or 6 dS/m. Plant height and dry weight and leaf Mg were decreased with increasing irrigation water salinity, whereas leaf Ca was increased at higher salinities. Leaf Mn and Zn increased, then decreased as salinity was increased. Leaf Ca and Mg increased with increased lime, but leaf Mn and Cu were decreased by increasing the lime rate. Leaf K increased, then decreased as lime rate was increased.
Natural distribution patterns of boron (B) among leaves within a canopy, among leaflets within a leaf, and within single leaflets were determined for coconut palm (Cocos nucifera L.) and within leaves for paurotis palm [Acoelorrhaphe wrightii (Griseb. & H. Wendl.) Becc.]. Leaf B concentrations did not vary significantly among leaves within the canopy or among leaflets within a single leaf for coconut palm, but basal leaflets of paurotis palm had higher B concentrations than central leaflets. Boron concentrations were significantly higher toward the tips of individual leaflets in both species. Application of Solubor to the soil significantly increased leaf B concentrations in all leaves of coconut palm after 2 months as well as in new leaves produced up to 6 months later. Application of Solubor as a leaf axil drench was much less effective in increasing foliar B concentrations than soil treatment.
Greenhouse-grown Tapeinochilus ananassae Hassk. were fertilized with 1110, 2220, or 4440 g of Osmocote 17N–3P–10K/m2 per year for 4 years. Plants receiving the medium rate of fertilizer produced the most flowers, while the highest fertilization rate resulted in the fewest. Flower stalk length decreased each year after planting, but cutting back the vegetative shoots to the ground resulted in increased flower stalk length the following year. Fertilization with the highest rate resulted in reduced flower postharvest life, but floral preservatives and ethylene inhibitors had no effect on postharvest life.
Three species of tropical shrubs, bush allamanda (Allamanda schottii), ixora (Ixora ‘Nora Grant’), and surinam cherry (Eugenia uniflora), were planted into a native sand soil and a calcareous fill soil in south Florida and were fertilized with a 24N–0P–9.2K (24–0–11) turf fertilizer or an 8N–0P–10K–6Mg plus micronutrients (8–0–12) palm fertilizer at rates of 10 or 20 g of nitrogen (N) per shrub four times per year. Two additional treatments using a 0–0–13.3K–6Mg plus micronutrients (0–0–16) palm fertilizer were applied at equivalent rates of potassium (K) (12.5 or 25 g/shrub of K) to that applied in the two 8–0–12 palm fertilizer treatments. Shrub size measurements, nutrient deficiency severity ratings, number of flowers, and shrub density ratings were determined at 6 months after planting (establishment period) and at 3 years after planting (maintenance phase). Data from these measured variables were subjected to principal component analysis to obtain a single measure of overall quality, namely, the scores for each plant on the first principal component. During the establishment period, ixora fertilized with the high rate of 8–0–12 had the highest quality on the sand soil, but there were no differences among treatments on the fill soil for this species or on either soil type for allamanda and surinam cherry. After 3 years of growth, ixora showed no differences in quality on either soil in response to the fertilizer treatments. On the sand soil, allamanda receiving the high rate of 24–0–11 or the low rate of 8–0–12 had significantly higher quality than unfertilized control plants, and the low rate of 8–0–12 produced the highest quality plants on the fill soil. Surinam cherry grown on sand soil had the highest qualities when fertilized with the high rates of either 24–0–11 or 8–0–12. In general, leaf nutrient concentrations were inversely correlated with overall shrub quality, with largest, highest quality plants having the lowest nutrient concentrations because of dilution effects. However, leaf manganese (Mn) concentrations were consistently within deficiency ranges for all species under most treatments, suggesting that Mn deficiency was stunting shrub growth on both soil types.
Pygmy date palms (Phoenix roebelenii `O'Brien') growing in a pine bark-Canadian peat-sand container medium and in a sandy field soil were fertilized with one of five commercially available Mn sources. Fertilization with Mn sulfate plus ammonium sulfate consistently increased Mn uptake above that of control palms. Four soluble Mn sources were applied to the foliage of container-grown palms, but only Mu sulfate consistently increased Mn concentrations in the leaves. Addition of urea, calcium hydroxide, or dimethylsulfozide did not improve Mn uptake from foliar sprays, and foliar sprays and soil applications were equally rapid in their effects on leaf Mn concentration.
Royal palms [Roystonea regia (HBK.) O.F. Cook], coconut palms (Cocos nucifera L. `Malayan Dwarf'), queen palms [Syagrus romanzoffiana (Chamisso) Glassman], and pygmy date palms (Phoenix roebelenii O'Brien) were grown in a rhizotron to determine the patterns of root and shoot growth over a 2-year period. Roots and shoots of all four species of palms grew throughout the year, but both root and shoot growth rates were positively correlated with air and soil temperature for all but the pygmy date palms. Growth of primary roots in all four species was finite for these juvenile palms and lasted for only 5 weeks in royal palms, but ≈7 weeks in the other three species. Elongation of secondary roots lasted for only 9 weeks for coconut palms and less than half of that time for the other three species. Primary root growth rate varied from 16 mm·week-1 for coconut and pygmy date palms to 31 mm·week-1 for royal palms, while secondary root growth rates were close to 10 mm·week-1 for all species. About 25% of the total number of primary roots in these palms grew in contact with the rhizotron window, allowing the prediction of the total root number and length from the sample of roots visible in the rhizotron. Results indicated that there is no obvious season when palms should not be transplanted in southern Florida because of root inactivity.
All leaves from 10 replicate Cocos nucifera L. `Malayan Dwarf' (COC) and Phoenix canariensis Chabaud (CID) trees were sampled for leaf nutrient analysis. In addition, the leaflets of the youngest fully expanded leaves and the third oldest leaves were divided into five groups along the primary leaf axis and these leaflets were then cut into thirds to determine nutrient distribution patterns within leaves and leaflets. Nutrient remobilization rates were calculated for N, P, K, Mg, and Mn. Results showed that N, P, and K were highly mobile within and between leaves of both species of palms. Up to 31% of the N, 66% of the K, and 37% of the total P in the oldest leaves were ultimately remobilized to newer leaves within the palm. Magnesium remobilization rates averaged ≈71% for CID but only ≈10% for COC. The middle-aged leaves appeared to be the primary sink for Mg in COC, rather than the youngest leaves as in CID. Manganese was also quite mobile in both species, with up to 44% of the total Mn remobilized in CID. Samples consisting of recently matured leaves were determined to be the most appropriate for Ca, Fe, Mg (COC only), and Zn, but oldest leaves are more suitable for N, P, K, and Mn analysis.
Spathiphyllum Schott. 'Mauna Loa Supreme' grown for 6 months in a fine sand soil or a 5 pine bark: 4 sedge peat: 1 sand medium (by volume) were fertilized with 7.6g N, 1.4g P, and 4.5g K/3.5-liter container by 4 different methods. The same raw fertilizer prills (21N-3P-12K) were applied weekly as a liquid, monthly as soluble granules, bimonthly as a lightly resin-coated fertilizer (Osmocote), or every 6 months as a heavily resin-coated fertilizer. All leachates were collected and were measured and analyzed weekly for N O3, PO4, and K. Spathiphyllum grew best in the sand soil with either of the controlled release formula- tions, but fertilization method had no effect on growth in the potting medium. Nitrate and K leaching losses from the potting medium were lowest from the controlled release fertilizers and highest from the soluble granules. Liquid fertilization resulted in the highest amounts of PO4 lost to leaching and controlled release fertilizers the least. In the fine sand soil, NO3 leaching was equivalent from all methods. Soluble granules had the highest levels of leached K and PO4 and the lightly-coated fertilizer lost the least due to leaching.
Palms are an increasingly important element in landscapes in the subtropical and warm temperate regions of the United States. Unfortunately, palms have very high nutritional requirements and rarely can be found without at least one nutrient deficiency, especially on the sandy and calcareous soils of the southeastern United States. These deficiencies are conspicuous and unsightly, reduce canopy size and vigor, and can become fatal. Current maintenance fertilizer recommendations for landscape palms in Florida growing in these soils entail four applications per year of an 8N–0.9P–10K–4Mg plus micronutrients palm fertilizer. However, because phosphorus (P) and nitrogen (N) are considered pollutants of ground and inland and coastal surface waters, it is important to apply only as much of these elements as necessary for palm health. This study showed that areca palms (Dypsis lutescens) can be grown in a native sand soil or in a calcareous fill soil without supplemental P and with no N applied during the rainy summer months of June through September when application of these elements may be legally restricted. It also demonstrated that the negative effects caused by high N:potassium (K) ratio turf fertilizers can be mitigated by adding a controlled release palm fertilizer that contains no N or P. Because of strong dilution effects in this study, leaf nutrient concentrations were found to be poor indicators of palm quality and nutritional status.