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- Author or Editor: Regina P. Bracy x
Field studies were conducted in Spring 1991, 1992, and 1993 to determine if stand deficiencies of 10%, 20%, or 30% affected bell pepper (Capsicum annuum L.) yield and fruit size. Subsequent replanting to a 100% stand and timing of replanting also were evaluated for effects on fruit yield. Stand deficiencies of up to 30% and replanting to a complete stand 2 or 3 weeks after initial transplanting did not affect yield per acre and average weight per fruit of bell pepper plants grown on polyethylene-mulched beds during 3 years of tests. Bell pepper plants grown in 10%, 20%, or 30% deficient stand had greater marketable yield per plant than plants grown in 100% stand. Replanting to a complete stand 3 weeks after initial transplanting decreased early marketable yield and production per plant over replanting 2 weeks after initial transplanting.
Bell pepper plant losses at transplanting may reduce yields. Growers often use subjective visual observations to determine reductions in plant stand but do not have a basis for determining if missing plants should be replaced or how soon. This study was initiated to determine effects of stand deficiencies and replanting on yield and fruit size of pepper during the spring 1992 and 1993.
`Jupiter' bell pepper plants were transplanted to the field in late March and spaced 30 cm apart on 1.2-m beds mulched with black plastic. Treatments included a control [0% stand deficient (SD)] and 10, 20, or 30% SD plots that were established at transplanting. Each SD treatment was replanted to a 100% stand two or three weeks after initial transplanting or was not replanted.
Yield of extra-large and marketable fruit was not affected by stand deficiencies or replanting in either year. Stand deficiencies up to 30% did not result in reductions in total/early yield or fruit size.
Field studies were conducted in 1993, 1994, and 1995 to evaluate chemical and biological agents for control of phytophthora blight in bell peppers grown on polyethylene-mulched raised beds. Treatments included Kocide 606 (foliar applied), Ridomil 2E (soil applied), Ridomil 2E (directed spray), Ridomil/Copper 70W (foliar), Ridomil 2E (soil) + Ridomil/Copper 70W (foliar), fluazinam (soil/foliar), and Actinovate bioconcentrate (seedling media applied). The experimental area was inoculated with Phytophthora 2 weeks after transplanting. All plants were rated for disease incidence (number of plants exhibiting visual symptoms) beginning at inoculation and continuing every week for 5–6 weeks. Disease incidence was severe in 1993 and 1995. None of the chemical or biological agents had an effect on total marketable yields or fruit weights during the three years. Disease ratings were highest in the control, Ridomil 2E (soil), and Actinovate plots. Yields did not reflect the severe disease infestation that occurred in some plots, possibly because greatest disease incidence occurred late in the season. Best Phytophthora control was obtained from chemical treatments containing copper compounds (Kocide and Ridomil/Copper 70W).
A precision seeder (Stanhay Model 870) and a bulk seeder (Planet Jr.) were used to evaluate the effects of precision seeding, seed spacing, and row configuration on yield and grade-out of two cultivars of root turnips. Seed spacings for the precision seeder included within-row (WIR) spacings of 56, 112, and 168 mm in single plant line/row and 112 and 168 mm in two plant lines/row. Seed spacings with the bulk seeder were obtained by using 100% viable seed or a 50% viable: 50% killed seed mix. The experiments were conducted during the spring and fall on two rows on a 1.2-m-wide bed. Total yield was not affected by plant population or seeder. Plant population, however, caused a shift in yield among grades. Yield of culls increased as plant population increased. Yield of extra-large (>114 mm) roots decreased as plant population increased. Turnips seeded 168 mm apart in a single line/row yielded more extra-large and large (25-114 mm) grade roots and less medium (4-24 mm) and cull (<4 mm or misshapen) roots. More consistent results were obtained with the precision seeder than the bulk seeder. During both seasons, yield was lower for the hybrid (`Royal Crown') cultivar than for the open-pollinated (`Purple Top White Globe') cultivar.
Two studies were conducted on bed and row configurations. The first compared erosion effects on stand count with single and double drill plantings; the second evaluated bed heights. Vegetables are usually planted on raised beds in the Deep South. Both single and double drills per bed are common. The double drills offer higher yields in some cases, but may be difficult to maintain because of erosion on the bed sides after heavy rainfall. A series of plantings of cabbage (Brassica oleracea L. Capitata group) and broccoli (Brassica oleracea L. Italica group) was made over a period of nearly a year to compare stands from single and double drills. Heavy rainfall did not occur after any of the 18 plantings, so bed erosion did not occur. Differences in percent stand were few, although in a few cases the double drill planting resulted in higher stands. A field study was conducted to determine the optimum bed height for leafy greens crops grown on shaped beds. Bed heights of 5, 10, 15, and 20 cm (2, 4, 6, and 8 in) were evaluated with crops of mustard [Brassica juncea (L.) Czerniak.] and turnip (Brassica rapa L. Rapifera group) during three crop seasons. Few significant differences in stand count, yield, or product quality resulted from the different bed heights. A trend toward lower yields, quality, and reduced efficacy of precision cultivation was noted with the 5-cm (2-in) bed height.
Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.
Selecting the proper seeder setup to effectively meter a given seed lot can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should be able to effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should be able to uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two cultivars of turnip (Brassica rape L. Rapifera group) were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder resulted in satisfactory singulation with any of the seed lots. With the larger [7/64 inch (2.8 mm)] belt holes, there were excessive incidences of multiple seeds per drop. With the smaller [6/64 inch (2.4 mm)] belt holes, multiple drops and missed seed were both excessive. The vacuum seeder also resulted in excessive misses and multiples.
An Earthway garden seeder (model 1001B) is frequently used for seeding small research and demonstration plots as well as home gardens. Seeding uniformity tests were conducted with 18 species of vegetable in this seeder using the planter plates recommended by Earthway, alternate plates, and plates modified by taping off metering ports to change the seeding rates and spacings. Performance with the Earthway seeder with most vegetable seeds would not qualify it as a precision seeder, but the Earthway seeder can do an acceptable job of planting many vegetable seeds in small plots at less than 1/10th the cost of a commercialquality precision seeder. A table giving specific recommendations for each of the 18 species has been prepared to aid research and extension personnel as well as home gardeners.
Stands of brassica crops obtained with precision seeders are sometimes inadequate or nonuniform. Although several types of covering devices and presswheels are available from precision seeder manufacturers, the effects of covering devices and presswheels on plant emergence of direct-seeded Brassica crops have not been determined. In Spring and Fall 1996, six crops of mustard [Brassica juncea (L.) Czerniak] and four crops of cabbage (Brassica oleracea L. capitata group) were direct seeded with a precision belt seeder using four covering devices and four rear presswheels. All of the covering devices and presswheels evaluated were adequate for direct seeding mustard and cabbage under the soil moisture conditions and soil type (silt loam or fine sandy loam) found in these experiments. Although poor stands were obtained with all seed covering devices and presswheels when 7.8 inches (199 mm) of rain occurred within 3 days of planting, plant stand of cabbage was greater when the paired arm device was used than with drag-type or no covering devices.
Selecting the proper seeder setup to meter a given seed lot effectively can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two turnip (Brassica rapa L. rapifera group) cultivars were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder satisfactorily singulated any of the seed lots. With the larger (7/64 inch) belt holes, there were excessive incidences of multiple seeds per drop. With the smaller (6/64 inch) belt holes, multiple drops and missed seed were excessive. The vacuum seeder also resulted in excessive misses and multiples.