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- Author or Editor: David G. Himelrick x
Nine grape cultivars (Vitis vinifera L., V. labruscana Bailey, and French-American hybrids) were evaluated in pot culture for their tolerance to strongly acid (pH 4.8) and slightly acid (pH 6.7) soil. Differences in cultivar tolerance to the strongly acid soil included a reduction in shoot and root dry weights and root volume. Based on root development, the most tolerant cultivars to the strongly acid soil were the V. labruscana cultivars Concord and Catawba and the V. riparia × V. berlandieri rootstock cultivar SO 4. The least tolerant vines were the two V. vinifera cultivars White Riesling and Chardonnay and the interspecific hybrid `Aurore'. No consistent treatment effects were found in foliar N, K, or B levels, but P and Ca were higher and Mg, Fe, Cu, and Zn lower in plants grown in the very acid soil.
Abstract
Apple (Malus domestica Borkh.) leaf, peel, and flesh tissues were sequentially fractionated using hot water, sodium nitrate, acetic acid and hydrochloric acid to extract Ca in various forms. Water soluble and sodium nitrate exchangeable Ca, which were considered to be the physiologically active forms, composed 53%, 78 %, and 73 % of the total Ca present in apple leaf, peel, and flesh tissues, respectively. Ionic Ca was determined in each of the fractions using an ion-selective electrode. Eleven to 42% of the total Ca concentration in each of the fractions was found to be in the free ionic form. Bound and exchangeable Ca in each of the fractions was also measured by an ion exchange resin in a batch method, and exchangeable Ca was 19 to 87% of the total.
The effect of seven types of plastic mulches on total, early, and late season yield was evaluated for three years in the annual hill strawberry production system. Black plastic mulches differed only from the significantly reduced yields found on unmulched bare ground treatments. Although not significantly different in any year, the top performing mulch treatments varied with production year and cultivar. In the wet and warm harvest season of 1991, the highest yielding treatments were IRT-76, clear, and ALOR-brown. In the dry and cool 1992 season, the top performers were white on black, black, and ALOR-brown. For the cool and moderately wet 1993 season, the best performance was recorded on black, white on black, and clear. Average soil temperatures from warmest to coolest were found with black, black on white, clear, IRT-76, ALOR-brown, red, silver, white on black, and bare soil treatments.
`Chandler' strawberry plants were established in a recirculating nutrient flow hydroponic system under six nutrient solution N levels (35, 70, 140, 210, 280, and 350 ppm). Various morphological and fruiting responses were measured. Average berry weight was greatest in the 280 ppm range and lowest in the 350 ppm solution N treatments. Percent soluble solids were greatest in the 35 ppm and lowest in the 140 ppm N treatments. Titratable acidity was greatest in the 75 and 210 ppm treatments and lowest in the 140, 280, and 350 ppm N treatments. Nitrate N was greatest in the juice of the 280 and 350 and lowest in the 35 ppm N treatment. Interior and exterior fruit firmness followed a general trend of the greatest firmness being found at 35 ppm and the least firm berries being from the 350 ppm treatment.
Generalized recommendations for the southeastern U.S. would typically include soil testing well in advance of establishment. Lime, P, and K should be applied at least 2 weeks before planting. Nitrogen is either broadcast and incorporated before planting or sidedressed 2 to 4 weeks after planting at 30 to 70 kg·ha–1. Additional N at 30 to 65 kg·ha–1 is applied late August to mid-September. A late winter N application at 20 to 30 kg·ha–1 is suggested for sandy soils. On established plantings fertilization takes place at renovation, with P and K being applied based on soil test or foliar analysis results. Nitrogen rates are typically in the range of 35 to 60 kg·ha–1. Later season fertilization generally follows the rates and timings of fall and winter recommendations of the establishment year. Minor nutrients can be limiting on sandy soils and B may be required in a wider range of soil types.
Abstract
Pretreatment or incubation of apple flesh tissue in CaCl2 solutions increased O2 consumption. Tissue incubated in ethylenediaminetetra-acetic acid (EDTA) and oxalic acid showed an initial respiratory burst with a subsequent decrease in respiration after 2 hours. Pretreatment alone did not induce a respiratory burst, but rather caused respiration to lag behind controls. The increased O2 consumption induced by CaCl2 was explained by the presumed restoration of membrane integrity in the senescing tissues which allowed a higher rate of respiration than expected.
Abstract
Six mid-season orchard sprays of ethylenediaminetetra-acetic acid (EDTA), oxalic acid, 2,3,5-triiodobenzoic acid (TIBA), and CaCl, did not consistently influence Ca concentration in leaf, fruit peel, or fruit flesh of 6 cultivars of apple (Malus domestica Borkh.).
Abstract
A rapid method for estimating total Ca of apple (Malus domestica Borkh.) peel and flesh was developed using a Ca-selective electrode to measure ionic juice Ca++. Ionic juice Ca++ ranged from 3.2 to 7.2 ppm. Significant correlations were found between total Ca and ionic juice Ca++ for flesh (r = 0.91) and peel (r = 0.87).