Studies were conducted to evaluate the effects of plant spacing, row arrangement, and N rate on bell pepper (Capsicum annuum L.) fruit production. Peppers were grown on a recently cleared sandy soil on raised polyethylene mulch beds during 2 years with one and two plant rows on 1.22-m beds and two and three plant rows on 1.83-m beds with two in-row plant spacings and two N rates. Marketable fruit production was similar during the 2 years. Yields per plant were 30% greater with a 0.31- than a 0.23-m in-row plant spacing. Even with the 33.3% larger number of plants per ha with the latter in-row spacing, yields per ha were similar with both in-row spacings. Yields per plant also varied with bed arrangement and were 50% greater with one row/1.22-m bed than with two rows/1.22-m bed or three rows/1.83-m bed. Plant populations were double with the two latter arrangements (53,818 plants/ha) than the former (25,909 plant/ha) arrangement with a 0.31-m in-row spacing. Thus, total yields were significantly greater with row arrangements with higher than lower plant populations. With three rows/1.83-m bed, the marketable fruit yields per plant were 19% lower for plants grown on the inside plant row than from plants grown on the outside plant rows. Leaf tissue N concentrations were higher during the season with 224 than with 135 kg N/ha, but yield was not influenced by N rate.
Salvadore J. Locascio and William M. Stall
Ramón A. Arancibia, Cody D. Smith, Don R. LaBonte, Jeffrey L. Main, Tara P. Smith, and Arthur Q. Villordon
to plant spacing and extension of the growing period to improve profitability of the production system intended for either fresh market or the processing industry. Sweetpotato producers targeting fresh market venues strive to achieve a large
Carl E. Motsenbocker, J. Blair Buckley, William A. Mulkey, and James E. Boudreaux
Field studies were conducted in 1991 with `Jalapeno-M' and `TAM' Jalapeno pepper. Plants were established by direct seeding at 10, 20, 30, and 40 cm in-row plant spacing. Lodged plants, fruit quality and yield were monitored. A commercial snap-bean harvester was evaluated for harvest. Closer plant spacings resulted in greater yields and reduced plant lodging. No interaction of variety with plant spacing was observed. There were, however, differences in several yield parameters due to variety. Fruit quality characteristics of mechanically and hand harvested pepper stored at 6 C were similar. The use of the mechanical snap-bean harvester appears to be a feasible technique to harvest Jalapeno pepper.
Carl E. Motsenbocker
Pepperoncini pepper (Capsicum annuum var. annuum L. `Golden Greek') was grown at in-row spacings of 7.5, 15, 22.5, 30, and 45 cm to determine the effect of plant population on growth and fruit yield in a 2-year field study. In 1992, pepper plants grown at the 15-cm in-row spacing had the lowest plant, stem, and leaf dry weights, while plants at the lowest density (45-cm spacing) had the highest plant, leaf, and stem dry weights and the largest leaf area (LA). Of plants grown at the 7.5-cm spacing, the total yield and fruit count per hectare were higher than at the other spacings; however, fruit yield per plant was lowest. In 1993, the lowest plant and leaf dry weights and LA and highest LA index (LAI) were from plants at the 7.5-cm in-row spacing. Plants at the 45-cm spacing had the highest plant and leaf dry weight and LA and the lowest LAI. Pepper plants grown at the narrowest spacing produced the lowest early and total fruit yield per plant but the most fruit per hectare. In general, plants grown at the narrowest spacings produced the smallest plant, leaf, and stem biomass but resulted in the highest fruit yields and counts per hectare and the lowest fruit yields per plant.
Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] cultivars StarBrite and Crimson Sweet were grown during 1991 and 1992 in rows 1.5 m apart at plant spacings of 0.9, 1.5, or 2.2 m. Total fruit yield, marketable fruit yield, fruit-weight distribution, and estimated gross returns were determined for each spacing treatment. Total and marketable fruit yields were greater overall for `StarBrite' than for `Crimson Sweet'. Except for 1991 `Crimson Sweet' yields, marketable fruit yields per unit land area increased 29% to 34% as plant spacing decreased from 2.2 to 0.9 m. The yield component contributing the most to increased yields with high-density plantings was increased fruit count per unit land area. Average fruit weight responded only slightly to decreased plant spacing. Fruit-weight distribution on a relative frequency scale was stable regardless of plant spacing or production year. The potential for increasing gross returns per unit land area exists by increasing watermelon plant populations beyond the current Georgia recommendation of 2500 to 3000 plants/ha.
Dean E. Knavel
Plant spacing or population studies with normal internode-length `Calypso' and short-internode Ky Littleleaf (Ky-LL), both gynoecious-flowering, in 6-row beds for once-over harvest in 1987, 1988, and 1989 showed that increasing spacing increased leaf area per plant, but had no effect on leaf area, fruit number, and total fruit weight in Grades 1, 2, and 3 per growing area. `Calypso' plants had more leaf area than Ky-LL, but both had similar number and weight of fruit. The best spacing for `Calypso' and Ky-LL was 15 × 21.5 cm for an average of 28.5 plants/m2 (283,570/ha). Ark Littleleaf (ARK-LL), a monoecious-flowering normal-internode length genotype, had more leaves and greater leaf area than `Calypso' and KY-LL plants. Increasing bed spacing of Ark-LL plants from 30 × 30 to 30 × 45 cm increased leaf area, fruit number and fruit weight per plant, but not per growing area. For fruit number and weight in Grades 1, 2, and 3, the best row spacing of Ark-LL plants was a single row of 15 cm or a 30 × 30 cm double row with fruit weight of 25,500 and 27,000 kg/ha, respectively. Data for the three plant types in various row spacings to be conducted in 1990 will be presented.
Elden J. Stang and Gavin G. Weis
`Raritan' and `Guardian' strawberry were grown in the matted row system with controlled plant densities of 1, 2, 3, 4 or 5 plants/0.09m2 for comparison to a non-thinned matted row averaging 9 plants/0.09m2. Nitrogen treatments were superimposed on plant spacings at 3 week intervals in preharvest and postharvest applications. Total seasonal available N was 0, 36, 54 and 76 kg/ha. Fruit yield per plant decreased as plant population increased. Berry size declined with increased plant population but number of fruit per plant was not influenced. For both cultivars, plant populations of 4 to 5 plants/0.09m2 resulted in maximum fruit yield. Number of branch crowns for all treatments was 2.5-3.5/plant in the second growing season. Branch crown numbers were reduced with higher plant populations. N effects were independent of plant population effects and did not compensate for lower yields at low plant populations in more or larger berries. Optimum water management may be more important than N fertilizer in determing strawberry plant growth and yield.
James N. Moore, Maurus V. Brown, and Bruce P. Bordelon
The influence of in-row plant spacing on the yield and fruit size of `Blueray' (erect growing) and `Bluecrop' (spreading) highbush blueberry (Vaccinium corymbosum L.) was studied. Plants of both cultivars, spaced at 0.61 m within the row, had significantly higher yields per hectare than plants grown at wider spacings (0.92 and 1.22 m) in each of five harvest years. On a per-plant basis, however, plants spaced at 1.22 m had higher yields in the last two harvest years of the experiment than plants spaced more closely, which indicated that interplant competition reduced per-plant yields of closely spaced plants as plants grew larger. Over the 5-year harvest period, plots with 0.61-m plant spacing produced a cumulative total yield of 17.24 t·ha more than plots with the conventional 1.22-m spacing. Plant spacing did not affect fruit size in this experiment.
Warren E. Copes and H. Scherm
Rhizoctonia web blight, caused by Rhizoctonia solani and binucleate Rhizoctonia spp., is an annual problem in compact cultivars of container-grown azalea (Rhododendron spp.) in the Gulf Coast states. Increasing the space between plants is commonly recommended for suppression of the disease, but experimental evidence for the effectiveness of this cultural practice in container-grown azalea is lacking. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 potted `Gumpo White' azalea plants growing in 3.8-L containers and having a canopy diameter of about 30 cm. Plant spacing within plots was 0, 6, 12, 18, or 24 cm, and plots were arranged in three randomized complete blocks. Evaporation, leaf wetness (LW), relative humidity (RH), and temperature were monitored in each plot. Disease severity increased steadily from mid-July to late August or early September, after which it leveled off or declined. Evaporation increased and the number of hours within the temperature range favorable for disease development (25 to 30 °C) decreased significantly with plant spacing (P < 0.05), but LW and RH were not significantly different among treatments. Plant spacing also had no significant effect on disease severity. Daily overhead irrigation and compact plant form likely contributed to the lack of effect of spacing on disease development.
Jonathon R. Schultheis, S. Alan Walters, and Edmund A. Estes
Yield in most crops can be increased with closer in-row spacing; however, the costs vs. benefits need to be assessed. A partial economic analysis was conducted at various plant spacings and harvest times to determine the best cultural management strategy. The effect of plant spacings (15.2, 22.9, 30.5, and 38.1 cm) and two dates of harvest (≈110 or 130 days after planting) were studied on `Beauregard' sweetpotato in one planting in 1991 and two planting locations in 1992. Weights were obtained for the U.S. Number 1, canner, jumbo, and cull grades. The 30.5-cm spacing interval was used as the standard comparison for economic analysis. Yields of sweetpotatoes increased as in-row spacing decreased. Based on economic analysis, the 38.1-cm spacing was always inferior to the 30.5-cm spacing. The preferred in-row spacing of `Beauregard' sweetpotato is 22.9 if a late harvest is anticipated, while the 15.2-cm spacing would be best if harvesting at ≈110 days after transplanting. As long as moisture is not limiting and planting is before mid-June, sweetpotato growers should place `Beauregard' plants at an in-row spacing of 15.2 or 22.9 cm, depending on projected date of harvest, to obtain the best yields with the highest marginal return on investment.