Interest in the production of the specialty vegetable radicchio (Cichorium intybus L. var. silvestre Bisch.) has increased among vegetable growers in the northeastern United States due to the popularity and consumption of premixed prepared salads. Growing environments with moderate daytime temperature and high light level have been associated with dense, deep red heads. Production problems include the low percentage of plants producing marketable heads and labor costs associated with hand-weeding. Traditional bareground culture was compared with several colored mulches (white, silver, red, black, and blue) for their effects on head formation, size, yield, and color of two Italian cultivars. Field studies were conducted in Freeville (upstate), N.Y., in 1997 and 1998. The percentage of heads harvested ranged from 32% to 82% over the 2 years of experiments and was lowest in black and red plastic mulch treatments. Yields were significantly higher, heads larger, and harvest earlier for plants grown over silver and white mulch compared to the control and other mulch treatments in 1998. In addition, average head weight was greater in all mulch treatments except blue when compared with the control. Cultivar differences were measured for the number and weight of heads, the percent bolting and marketable heads, and head color in 1998. Air and soil temperatures varied significantly around these mulches; however, these differences in microclimate had no effect on head color quality. Despite relatively moderate temperatures in upstate New York, radicchio responded positively to mulches that lowered average soil temperatures (white and silver) compared with the other treatments.
Anusuya Rangarajan and Betsy Ingall
Anusuya Rangarajan and Betsy A. Ingall
Annual production of globe artichokes (Cynara scolymus L.) requires vernalization of the plants, either through cold treatment of transplants or from natural temperature conditions in the spring. Studies were conducted in upstate New York to determine if artificial vernalization treatments could be achieved by earlier planting dates. Initial trials evaluated two cultivars used for annual production in other parts of the country—'Imperial Star' and `Green Globe Improved'. Transplants were set in the field with or without a vernalizing cool treatment, to determine the extent of natural vernalization achieved under New York conditions. `Imperial Star' produced slightly higher marketable yields than `Green Globe Improved' in 2 years of trials. Vernalization treatment increased the number of plants producing buds and the marketable yields, when transplants were set after 15 May. Natural vernalization was achieved and cold treatment prior to transplanting did not improve yields of plants established in early May. At later planting dates, vernalizing transplants increased the number of plants producing apical buds (largest) by about 20%, yet, >57% of non-vernalized plants of each variety produced buds within the season. Average bud sizes did not vary with vernalization treatment. A similar number of days from transplanting to first bud harvest (69 to 75) was noted regardless of planting date and size of transplant.
Anusuya Rangarajan, Betsy A. Ingall and Victoria C. Zeppelin
Annual production of globe artichokes (Cynara scolymus L.) requires vernalization of the plants, either through cold treatment of transplants or from natural temperature conditions in the spring. Studies were conducted in upstate New York, to determine if artificial vernalization treatments could be achieved by earlier planting dates. Initial trials evaluated two varieties used for annual production in other parts of the country—`Imperial Star' and `Green Globe' Improved. Transplants were set in the field with or without a vernalizing cool treatment, to determine the extent of natural vernalization achieved under New York conditions. `Imperial Star' produced slightly higher marketable yields than `Green Globe Improved' in 2 years of trials. Vernalization treatment increased the number of plants producing buds and the marketable yields, when transplants were set after 15 May. Natural vernalization was achieved and cold treatment before transplanting did not improve yields of plants established in early May. At later planting dates, vernalizing transplants increased the number of plants producing apical buds (largest) by about 20%, yet over 57% of nonvernalized plants of each variety produced buds within the season. Average bud sizes did not vary with vernalization treatment. A similar number of days from transplanting to first bud harvest (69 to 75 days) was noted regardless of planting date and size of tran.
Anusuya Rangarajan, Betsy A. Ingall, Michael D. Orzolek and Lewis Otjen
Butternut squash (Cucurbita moschata) plants are susceptible to defoliation and plant population (stand) reduction by insect, disease, temperature extremes, water, hail, or other mechanical damage. The timing of such losses may have variable effects on final fruit quality and yield. The objectives of these studies were 1) to determine the influence of the degree and timing of defoliation and stand reduction on the marketable yield of winter squash; 2) to determine yield compensation after stand reduction and defoliation; and 3) to explore effects of defoliation on fruit total carotenoid content. Experiments were conducted over 2 years in New York and Pennsylvania to explore these objectives. Marketable yields consistently improved with increasing plant population. If population losses occurred while plants were in the rapid vegetative growth phase, the remaining plants responded by increasing fruit number and weight per plant. Plant losses later in the season during fruit enlargement, however, did not elicit the same magnitude of response. Defoliation of 66% leaf area reduced marketable yields, and effects were most severe under high plant populations. Competition among plants restricted compensation. Moderate defoliation (33%) reduced yield in only one of three studies. This level of defoliation also increased the percentage of medium [1.0 to 1.5 kg (2.20 to 3.31 lb)] and large [1.5 to 2.0 kg (4.41 lb)] fruit and decreased the number of jumbo fruit (>2.0 kg). Total carotenoid concentration in mature fruit was unaffected by the defoliation or population treatments. Thus, butternut squash compensated for up to 33% leaf area loss at any time during the season. While the crop could compensate, under some conditions, for up to 50% plant losses, final plant population was more important than the growth stage of damage or defoliation for effects on crop yield.
Anusuya Rangarajan, Betsy Ingall, Michael Orfanedes and David Wolfe
Early-planted fresh market sweet corn (Zea mays) is prone to nonuniform ear length and quality due to uneven germination in cool soils. Growers compensate by reducing in-row spacing at seeding, to increase final plant stand. This risk management strategy was suspected to be reducing quality of early-planted sweet corn, based upon buyer feedback. Four experiments were conducted in upstate New York, to examine the effects of in-row spacing and cultivar on early-planted sweet corn ear yield, length and uniformity. Cultivars examined included `Temptation' (4 years), `Sweet Symphony' (3 years) and `Seneca Spring' (2 years). In-row spacings tested ranged from 6 to 9 inches (15.2 to 22.9 cm), using a 30-inch (76.2-cm) between-row spacing. In-row spacing and cultivar influenced marketable yield, husked ear weight and length of early-planted corn, but the extent varied by year. Despite improvements in individual ear weight and length at wider in-row spacing, marketable yield was usually higher at more narrow spacings. Increases in ear weight at wider spacings were usually associated with increases in weight of the outer, green husk. Average ear length of a cultivar varied between 0.2 and 0.6 inches (0.5 to 1.5 cm) in response to spacing. If ears longer than 7 inches (17.8 cm) were desired, 40% to 60% of ears satisfied this criteria if harvested from plants grown at 8-inch (20.3-cm) in-row spacing or a plant population of 26,000 plants/acre (64,200 plants/ha). Ear weight and length of `Seneca Spring' was not as affected by the in-row spacing treatments compared to the other two cultivars, perhaps due to the small size of this cultivar. Selection of smaller sized sweet corn cultivars for planting at high plant populations (6-inch in-row spacing) may reduce the variation in ear weight under challenging early season conditions. For cultivars with similar growth characteristics and maturities of `Temptation' and `Sweet Symphony,' a minimum in-row spacing of 8 to 9 inches or a plant population of 23,200 to 26,000 plants/acre (57,300 to 64,200 plants/ha) was recommended to minimize variation in ear yield and quality from first bareground plantings in the northeastern United States.
Anusuya Rangarajan, Betsy A. Ingall and Michael S. Orfanedes
Early fresh-market sweet corn expressed concern is prone to variability in ear length and quality due to uneven germination rates in cooler soils, smaller plant size of early corn, and single ear per stalk trait of early varieties. In an informal survey of current practices, growers reported using in-row spacings between 0.5 and 0.25 m (0.76 m between rows) for their first bare-ground corn, representing a range of plant populations from 86,000 to 43,000 plants/ha. However, no information had been gathered on the impacts of these various in-row spacings on early corn ear length and overall quality and how different sweet corn types (se, sh2, sweet breeds) might respond to these spacings under cool conditions of early spring. Four trials were conducted over the last 2 years, in upstate New York, examining three sweet corn types, five plant populations, and two nitrogen sidedress rates for effect ear length, quality, and uniformity. In general, results thus far indicate that all three parameters can influence ear quality and variability. Among treatments, ear length varied by up to 1 cm. The variety `Sweet Symphony' was less affected by high populations than `Temptation'. In 1998, no difference in ear length due to spacing was found. It is suspected that the warm spring in 1998, coupled with adequate moisture, reduced plant stress during early growth. Higher nitrogen sidedress rates reduced variability of early season corn, at all populations. In 1999, plant population was found to be the most important factor affecting ear physical characteristics.
David W. Wolfe, Daniel T. Topoleski, Norman A. Gundersheim and Betsy A. Ingall
A 3-year field study conducted on an Eel silt loam soil (Aquic Udifluvent) compared cabbage (Brussica oleracea L. capitata group), cucumber (Cucumis sativus L.), snap bean (Phaseolus vulgaris L.), and sweet corn (Zea mays L.) for their growth and yield response to an artificially compacted soil layer beginning at about the 10-cm depth. Slower growing cabbage seedlings in compacted plots were more subject to flea beetle damage than the uncompacted controls. Prolonged flooding after heavy rainfall events in compacted areas had a more adverse effect on cabbage and snap bean than on cucumber or sweet corn. Sweet corn showed almost no growth reduction in one of the three years (1993) when relatively high fertilizer rates were applied and leaf nitrogen deficiencies in compacted plots were prevented. Maturity of cabbage, snap bean, and cucumber was delayed, and the average reduction in total marketable yield in (direct-seeded) compacted plots was 73%, 49%, 41%, and 34% for cabbage, snap bean, cucumber and sweet corn, respectively. Yield reduction in transplanted cabbage (evaluated in 1993 only) was 29%. In a controlled environment greenhouse experiment using the same soil type and similar compaction treatment as the field study, compaction caused a reduction in total biomass production of 30% and 14% in snap bean and cabbage, respectively, while cucumber and sweet corn showed no significant response. The growth reductions of snap bean and cabbage in the greenhouse could not be attributed to compaction effects on soil water status, leaf turgor, nutrient deficiency, or net CO, assimilation rate of individual leaves. Root growth of sweet corn was least restricted by the compacted soil layer. The contrast between our field and greenhouse results indicates that the magnitude of yield response to compaction in the field was often associated with species sensitivity to secondary effects of compaction, such as prolonged flooding after rainfall events, reduced nutrient availability or uptake, and prolonged or more severe pest pressure.