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- Author or Editor: D. L. Craig x
Succinic acid-2,2-dimethylhydrazide (SADH) applied as 1000 and 2000 ppm sprays to ‘Trent’ and ‘Canby’ red raspberries on 4 dates during the 1970 and the 1971 growing seasons did not effect bud survival, yield, or number of flowers per lateral. Inconsistent reductions occurred in berry weight, number of flowering laterals, and buds per cane diameter. In all instances cane height was reduced.
Size and number of plots is an important consideration for strawberry breeders and other researchers engaged in the evaluation of strawberry cultivars. Edgar (2) found at East Mailing that plots of about 50 plants planted on the square were best, but Taylor (3) considered the variability in Edgar’s plots to be abnormally low, and advocated plots of 24 plants arranged in a twin row. He considered that seven replicates were necessary to measure a 20 percent difference at the 5 percent level of probability. Baker and Voth (1) in California considered 3 plots of 50 plants or 8 of 25 plants necessary to reduce heterogeneity to an acceptable level for scoring clones for resistance to Verticillium wilt in a “wilt nursery.” All of these researchers were working with strawberries on the hill system, whereas the matted row system is standard in Eastern North America.
In a field experiment with the cultivar ‘Bluecrop’, N and K levels in leaves and fruit increased but Ca levels decreased as rate of (NH4)2SO4, urea, or NH4NO3 increased. There were no differences due to source of N. In a 3-year period application of a total of 5.07 oz/bush of MgSO4·7H2O had no effect on Mg levels in leaves or fruit.
(2-Chloroethyl)phosphonic acid (ethephon) at 250 ppm controlled bud and flower abscission but not young pod abscission of ‘Dark Red Kidney’ bean. Leaf abscission was unaffected, intemodal elongation was temporarily retarded, and the number of seeds but not the number of pods produced exceeded that of untreated plants but the difference in seed production was not significant. Treatment with 500 ppm ethephon resulted in a pattern of abscission similar to that of untreated plants. At higher concentrations (1000 and 2000 ppm) abscission of reproductive structures and of leaves was promoted. Seed production, seed maturity, and seed size were reduced. New leaves were pendant and were smaller than those of untreated plants.
Field trials with grape cultivars, conducted at three locations in the Annapolis-Cornwallis Valley in Nova Scotia, show that the successful growth of wine cultivars is not feasible. While there were differences between locations, apparently lack of sufficient heat units to fully mature the fruit is responsible for the area’s unsuitability.
We compared the potential for foliar dehydration tolerance and maximum capacity for osmotic adjustment in twelve temperate, deciduous tree species, under standardized soil and atmospheric conditions. Dehydration tolerance was operationally defined as lethal leaf water potential (Ψ): the Ψ of the last remaining leaves surviving a continuous, lethal soil drying episode. Nyssa sylvatica and Liriodendron tulipifera were most sensitive to dehydration, having lethal leaf Ψ of –2.04 and –2.38 MPa, respectively. Chionanthus virginiana, Quercus prinus, Acer saccharum, and Quercus acutissima withstood the most dehydration, with leaves not dying until leaf psi dropped to –5.63 MPa or below. Lethal leaf Ψ (in MPa) of other, intermediate species were: Quercus rubra (–3.34), Oxydendrum arboreum (–3.98), Halesia carolina (–4.11), Acer rubrum (–4.43), Quercus alba (–4.60), and Cornus florida (–4.88). Decreasing lethal leaf Ψ was significantly correlated with increasing capacity for osmotic adjustment. Chionanthus virginiana and Q. acutissima showed the most osmotic adjustment during the lethal soil drying episode, with osmotic potential at full turgor declining by 1.73 and 1.44 MPa, respectively. Other species having declines in osmotic potential at full turgor exceeding 0.50 MPa were Q. prinus (0.89), A. saccharum (0.71), Q. alba (0.68), H. carolina (0.67), Q. rubra (0.60), and C. florida (0.52). Lethal leaf Ψ was loosely correlated with lethal soil water contents and not correlated with lethal leaf relative water content.
Preharvest sprays of CaCl2, Ca(NO3)2, or water soluble wax increased berry size (by wt) and decreased the rate of softening during storage for 48 hr at 21°C. In a split plot experiment, with 4 cvs. and 3 dates of harvest, preharvest sprays of wax increased firmness but had no effect on total acidity, acid loss, water loss, or fungal decay. There were, however, significant interactions between cvs. and harvest dates in relation to firmness, acidity, and rot development.
Recent concerns over the environmental impact of peat harvesting have led to restrictions on the production of peat in Florida and other areas. The objectives of this study were to evaluate the use of composted dairy manure solids as a substitute for sphagnum or reed-sedge peat in container substrates on the growth of Solenostemon scutellarioides L. Codd ‘Wizard Velvet’, Tagetes patula L. ‘Safari Queen’, and Begonia ×hybrida ‘Dragon Wing Red’ and to examine the nutrient content in leachate from pots. Plants were grown for 5 weeks in a greenhouse in 15-cm plastic pots with seven substrates containing various proportions of sphagnum peat (S) or reed-sedge peat (R) and composted dairy manure solids (C), each with 20% vermiculite and 20% perlite. Substrate composition had no effect on plant quality ratings, number of flowers, or root dry mass for any of the plant species evaluated. Substrate composition did not affect the growth index (GI) or shoot dry mass of S. scutellarioides ‘Wizard Velvet’ or the GI of T. patula ‘Safari Queen’. However, growth of B. ×hybrida ‘Dragon Wing Red’ (GI and shoot dry mass) and T. patula ‘Safari Queen’ (shoot dry mass only) was highest in the 3S:0R:0C substrate. The substrates containing sphagnum peat and/or composted dairy manure solids (3S:0R:0C, 2S:0R:1C and 1S:0R:2C) had the highest NH4-N losses through the first 7 d of production. The 0S:3R:0C substrate had the highest initial leachate NO3+NO2-N losses and this trend persisted throughout most of the production cycle. Significantly more dissolved reactive phosphorus was leached from substrate mixes containing composted dairy manure solids than mixes containing only sphagnum or reed-sedge peat materials through 19 d after planting. All substrates tested as part of this study appeared to be commercially acceptable for production of container-grown bedding plant species based on plant growth and quality. However, nutrient losses from the containers differed depending on the peat or peat substitute used to formulate the substrates.
The urban soil environment is usually not conducive to healthy root growth and function, leading to problems with plant establishment, growth, and aesthetic quality. The objective of this study was to determine if the addition of compost with or without the application of shallow tillage or aeration will improve soil physical and chemical properties and plant growth compared with an unamended control in simulated new residential landscapes. Twenty-four mixed landscape plots were established in a randomized complete block design to simulate new residential landscapes. Each plot was constructed using 10 cm of subsoil fill material over a compacted field soil and planted with Stenotaphrum secundatum and mixed ornamental plant species. Composted dairy manure solids were applied as an organic soil amendment at a depth of 5 cm (≈256 Mg·ha−1) in combination with two mechanical soil treatments (tillage to 15 cm and plug aeration) for a total of five soil management treatments plus an untreated control. Soil physical and chemical properties, plant growth, and quality and plant tissue nutrient concentrations were assessed periodically to determine the effect of soil treatment on soil and plant quality. Applications of compost to soils significantly reduced soil bulk density and pH and increased soil organic matter, electrical conductivity, and Mehlich-1 phosphorus and potassium concentrations. All ornamental plant species, with the exception of Raphiolepis indica (L.) Lindl. ex Ker Gawl., exhibited more growth when grown in soils amended with composted dairy manure solids. In most instances, plant tissue nitrogen and phosphorus concentrations were higher for plants grown in soils receiving compost. Results of our study suggested that the addition of composted dairy manure solids to soils can improve soil properties and enhance plant growth in residential landscapes when sandy fill soils are used. In contrast, shallow tillage and aeration had little effect on soil properties or plant growth.