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- Author or Editor: David G. Himelrick x
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.
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.
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.
`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.
`Chandler' strawberry plants were grown in a nutrient flow hydroponic systems with six solution N treatments (35, 70, 140, 210, 280, 350 ppm). Plant architecture was influenced by solution N levels with 350 ppm producing small dark green leaves with short petioles while 35 ppm produced light green leaves with large leaf blades and long petioles. Other treatments were intermediate but similar to the 35 ppm with darker green foliage. The 210 ppm treatment produced the most runners per plant while the 350 ppm treatment produced the least. The 210 ppm treatment produced the most crowns per plant while the 35 ppm treatment produced the least. The highest seasonal fruit yield and largest berry size was produced in the 70 ppm treatment with the 350 treatment having the lowest yield and smallest berry size.
A number of strawberry cultivars and breeding line selections have been tested in the annual plasticulture system. The only two cultivars currently recommended based on cultural and economic performance ate 'Chandler' and 'Oso Grande'. Plant type (fresh dug, plug, etc.) and nursery source have also been evaluated. Fresh dug plants with leaves intact generally perform better than those with leaves removed. Rooted runner tips in cell packs (plug plants) look very promising and outperform fresh dug plants in most situations. Plastic mulch treatments included clear (CLR), black (BLK), laminated white on black (W/B), laminated black on white (B/W), IRT-76 (IRT), AL-OR brown (ALOR), and a bare ground (BG) check. In the first season the highest yields for 'Chandler' were obtained on IRT, followed by CLR, ALOR, B/W, BLK, W/B, and BG. The highest yields for 'Selva' were on CLR followed by BLK, ALOR, IRT, B/W, W/B, and BG. In the second season the highest yields for 'Chandler' were on W/B followed by BLK. ALOR, IRT, B/W, CLR, and BG. In the case of 'Selva' ALOR was the top performing treatment followed by IRT, W/B, BLK, B/W, BG, and CLR.
`Chandler' strawberry plants were grown in a nutrient flow hydroponic systems with six solution N treatments (35, 70, 140, 210, 280, 350 ppm). Total N was determined in leaf blade and petiole samples using Kjeldahl procedure and by LECO CHN analyzer. Nitrate-N was extracted with KCl and analyzed using a LACHAT ion analyzer. Correlations for total N in leaf blades with hydroponic N levels were r7 = 0.79 for Kjeldahl, r2 = 0.25 for LECO, and r2 = 0.60 for LACHAT while petiole samples were r* = 0.57 for Kjeldahl, r2 = 0.55 for LECO and r2 = 0.41 for LACHAT. Vegetative characteristics of the plants were affected with the 210 ppm treatment producing both the most crowns and runners and 350 ppm the least.
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.