Prior studies have demonstrated that a Gaspardo vacuum seeder provides less uniform seed spacing than a Stanhay belt seeder. It was hypothesized that the difference was primarily because of the greater seed drop height on the Gaspardo seeder. A Gaspardo metering unit was modified by adding a slide or an enclosed tube to guide the seeds from the release point (seed plate) to 1.0 inch (25 mm) above the bottom of the seed furrow. Seed uniformity tests were conducted with cabbage (Brassica oleracea), onion (Allium cepa), and mustard (Brassica juncea) seeds. The modified planter unit was compared with an unmodified unit. No improvement in seeding uniformity was noted with either the slide or the tube. In fact, seed placement uniformity was degraded with the addition of the slide and tube. Although it is probable that the seed spacing nonuniformity was caused by drop height, attempts to control the seed trajectory were unsuccessful.
R.L. Parish and R.P. Bracy
R.P. Bracy, R.L. Parish, and E.B. Moser
Field studies were conducted in Fall 1991 and 1992 to determine if cauliflower (Brassica oleracea L. Botrytis Group) could be precision seeded to a stand without subsequent thinning and what the optimum seed spacing necessary to directly seed cauliflower to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and early harvest percentage. As evaluated in the laboratory, seeder precision (accuracy) was good with regard to seed counts and spacing measurements at the various seed spacings. Seeder precision evaluated in the field varied in distribution patterns among seed spacings and years. Cauliflower was successfully precision seeded to a stand without thinning during 2 years of fall plantings. Cauliflower directly seeded at one seed per hill and a 20-cm spacing produced total and average head weights similar to cauliflower seeded 10 cm apart and thinned to 30 cm—the seeding method currently used by some commercial operators.
R.P. Bracy, R.L. Parish, and J.E. McCoy
Difficulty in obtaining and maintaining an adequate plant stand in directly seeded cabbage led to the investigation of possible causes of plant loss. A series of experiments was conducted evaluating the effect of six rates (0, 0.28, 0.41, 0.56, 0.84, 1.12 kg·ha–1 a.i.) of trifluralin on cabbage stand. The treated area was irrigated immediately after planting; one-half of the area received overhead irrigation and the other half received furrow irrigation. Activated charcoal as a slurry was sprayed at the rate of 336 kg·ha–1 directly into the seed furrow on half the plots receiving the higher trifluralin rates. Plots treated with trifluralin at rates of 0.56, 0.84, and 1.12 kg·ha–1 had lower plant populations if activated charcoal was not applied. Grass, broadleaf, and sedge weed control was as effective with 0.28 and 0.41 kg·ha–1 of trifluralin as it was at the higher rates of 0.56, 0.84, and 1.12 kg·ha–1. Plant population was not affected as much by trifluralin rates when furrow irrigation was used as compared with overhead irrigation. Producers should be careful not to exceed 0.41 kg·ha–1 of trifluralin on cabbage directly seeded into light-textured soils, because reduced stands can be expected.
R.L. Parish, R.P. Bracy, and W.C. Porter
The Precision Cultural System (PCS) developed by the Louisiana Agricultural Experiment Station allows simple and precise cultivation of vegetable crops; however, speed of the cultivators in small vegetable crops has been limited. The standard PCS sweep cultivator was limited to about 1.6–2.4 km·h–1 in small crops because it would throw soil over the crop plants at higher speed. The standard PCS rotary tiller cultivator could operate at 3.2–4.8 km·h–1 in small crops but could not be operated faster in larger crops, due to its tendency to “walk” out of the soil at higher speeds. The standard PCS sweep cultivator was modified by replacing the sweeps between the twin drills with two pairs of straight finger-wheel (“rolling cultivator”) spiders non-angled and in tandem. The finger-wheel gangs on the bed sides were also inactivated by raising them above the soil. The resulting PCS cultivator was successfully operated in very small crop plants (≤25 mm high) at speeds of 8–10 km·h–1 with no crop damage. The cultivator could then be easily refitted for standard sweep cultivation on subsequent passes. No reductions in weed control or yield of mustard, kale, turnip, or spinach were noted when using the high-speed system.
R.L. Parish, R.P. Bracy, and H.F. Morris Jr.
A study was conducted to evaluate the effect of banding or broadcasting fertilizer on yield and quality of turnip (Brassica rapa L. Rapifera group), sweetcorn (Zea mays var. rugosa Bonaf.), and cabbage (Brassica oleracea L. Capitata group). Preplant fertilizer was applied broadcast before bedding, broadcast after bedding, or banded after bedding. Sidedress applications were broadcast or banded on the beds. Differences in plant size and vigor were noticed early in the season in the spring turnip crop, with the growth in the broadcast-and-bed treatment appearing superior. The yield at first harvest and total yield were lower for turnip grown with the bed-and-broadcast treatment. No differences in yield of cabbage or sweetcorn resulted from the treatments. Few differences in turnip stem-to-leaf ratio were noted due to fertilizer treatment. Few differences in yield due to sidedress method were noted with any of the crops. Analysis of soil samples in a grid pattern across the beds showed that the location of the fertilizer after the broadcast-and-bed treatment was similar to the placement of the banded fertilizer. Since broadcasting can be done with a faster, wider applicator, growers could reduce costs by broadcasting fertilizer and obtain yields that are at least equivalent to the yields obtained by banding the fertilizer.
Regina P. Bracy, R.L. Parish, and W.A. Mulkey
A cultural system consisting of precision seeding on shaped beds, followed by cultivation using mechanically guided equipment, was developed and evaluated with several vegetable crops. The precision cultural system allowed for growing the crops at high plant populations by using precision planting and exact cultivation of multiple narrow rows of plants on wide beds. Eight field experiments were conducted from 1987 to 1989 on broccoli (Brassica oleracea var. botrytis L.), cabbage (Bra&a oleracea var. capitata L.), mustard (Brassica juncea var. crispfolia L.), and spinach (Spinacia oleracea L.) to evaluate production of these crops on single- and multiple-row configurations on narrow (1 -m) and wide (2-m) beds. The precision cultural system was assessed to be an excellent method for production of the small-seeded crops that were tested. Yield was highest for cabbage, mustard, and spinach planted in six rows on 2-m beds compared with four-, two-, or one-row beds. Multiple-row configurations did offer yield advantages over the single-row configuration for broccoli production.
R. P. Bracy, R. L. Parish, P. E. Bergeron, E. B. Moser, and R. J. Constantin
A study to evaluate the seeding rate necessary for precision seeding cabbage to a stand was initiated during the spring of 1989. A Stanhay precision seeder was used to plant cabbage seed at 10-cm (thinned to 30-cm), 20-cm, 30-cm (1 seed/hill), and 30-cm (2 seed/hill) spacings. Total weight was not significantly affected by seed spacing, but head size decreased with an increase in number of heads. Cabbage spaced 30 cm (1 seed/hill) apart produced the highest yield of marketable heads (1007 gms). Lab measurements were determined by operating the planter over a lubricated board and measuring seed spacing. Lab measurements of spacing indicated actual spacing was closely associated with expected spacing of each treatment. Field measurements of plant spacing were used to associate seed placement between lab and field spacings. Graphical analysis indicated spacing within a treatment was similar in both lab and field treatments. Small differences between data collected in the lab or field were attributed to loss of plants in the field.
R.P. Bracy, R.L. Parish, P.E. Bergeron, and E.B. Moser
A precision cultural system proved successful for growing broccoli in multiple rows of plants on narrow or wide beds. Higher production obtained from planting in the multiple-row configurations, however, was not proportional to the increase in number of rows. To quantify the optimum rate of fertilization on multiple rows per bed, broccoli was grown during the spring and fall, 1990, in one row/1-m beds, two rows/1-m beds, or six rows/2-m beds with fertilizer rates ranging from 448 to 1,680 kg·ha-1 of 9N-12P-22K and 150 to 560 kg·hg-1 of ammonium nitrate. During both seasons, fertilizer rate had an overall linear effect on the yield but did not affect average head weight. Response to fertilizer rates was greatest when broccoli was grown in six rows/2-m beds. Broccoli grown during the spring showed a greater response to fertilizer rates than did broccoli grown in the fall.
Regina P. Bracy, Richard L. Parish, Paul E. Bergeron, E.B. Moser, and R. J. Constantin
Field studies were conducted in Spring 1989 and 1990 to determine if cabbage (Brassica oleracea L. Capitata Group) could be precision-seeded to a stand without subsequent thinning and to determine the optimum seed spacing necessary to seed cabbage directly to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and harvest percentage. Seeder precision (accuracy) with regard to seed counts and spacing measurements at the various seed spacings, as evaluated in the laboratory, was good. Seeder precision evaluated in the field varied in distribution patterns among seed spacings and years. Cabbage directly seeded at one seed per hill and a 30-cm spacing produced yields and head weights similar to or higher than cabbage seeded 10 cm apart and thinned to 30 cm-the seeding method currently used by some commercial operators.