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- Author or Editor: Richard Parish x
A study was conducted in 2004 comparing commercial plant restraint systems with a grower standard consisting of a steel rod driven through the container into the soil. Commercial systems included wire baskets, aboveground plastic pot-in-pot, trellis with straps, and brackets on individual posts. This test was conducted on 15-gallon containers. Costs and efficacy of the systems were recorded. All of the commercial systems worked well, but the annualized cost of the grower standard was much less even though more blow-over occurred with the grower standard. A different system consisting of a horizontal rod over the top of containers and held down with J-stakes was tested on 4-gallon containers. Not enough stakes were used and the system was less effective than vertical stakes in each pot. A new study was initiated in 2005 to refine the grower standard through the use of one or two stakes per container, longer stakes, and the use of rebar instead of smooth rod. More stakes, longer stakes, and rebar were also evaluated with the horizontal rod system. The 2005 test was lost due to Hurricane Katrina. It will be repeated in 2006.
A new slow-release powdered fertilizer product has been developed for use in the landscape industry. A series of tests was conducted to evaluate this product in several landscape applicator modes: turf broadcast, turf gun, and soil injection (for trees). Variables included concentration, nozzle size and type, pressure, agitation, and holding time in the tank before spraying. The product worked well in a wide variety of spray equipment and operating conditions. It could be sprayed at a rate of 0.030 kg N/L in nozzles as small as DG 8002 (0.011 L·s–1 flow rate) without nozzle plugging and at rates of up to 0.060 kg N/L in larger nozzles. The product settled out of suspension rapidly, so good agitation was critical. No differences were noted due to nozzle type or spraying pressure. Suspensions could be held overnight if properly reagitated before spraying. Foaming was a problem with this product. An antifoam agent should be considered. Large-diameter filters minimized problems.
Flame “cultivation” for weed control was developed about 50 years ago. The practice was very popular with Southern cotton farmers through the 1950s and 1960s, but lost favor when petroleum prices rose drastically in the 1970s. There is now a new interest in the practice of flame cultivation as a partial or total replacement for herbicides in vegetable crops. This interest is fueled by three factors: 1) an increasingly negative public perception of herbicides on vegetables, 2) a very limited selection of herbicides labeled for vegetables, and 3) limited efficacy of some of the herbicides that are registered. Flame cultivation, in combination with mechanical cultivation, can replace or supplement herbicides in some vegetable crops. The mode of action of flame cultivation is the bursting of cell walls in the weeds as the weeds are heated by a carefully directed LP gas flame. With most vegetable crops, the crop plants must be protected in some manner. This can be done with a water shield (flat fan water spray), height differential between weeds and crop, physical shield, etc. Much of the early work on flame cultivation of vegetables was done with sweet corn. Work is now underway on flame cultivation of lima beans and southernpeas, where multiple flame cultivations have proven effective at controlling weeds for which no herbicide is available.
This article is a review of the current status in planting and transplanting equipment and practices for vegetable crops. A review of horticultural and agricultural engineering literature is supplemented by information from an informal survey of members of American Society of Agricultural Engineers (ASAE) committee PM-48, Fruit and Vegetable Production Engineering, and other engineers and horticulturists working in this field. Areas covered include precision seed metering, seed placement, and high-speed transplanting with automated plant handling.
A simple, inexpensive device to measure the linear tear strength (tensile strength) of a strip of turfgrass sod was constructed for use in a research program. The device was fabricated from readily available components. A standard torque wrench served as the force-measuring device, providing torque readings that were converted readily to linear force measurements. The device worked very effectively.
Application of granular materials is an important part of most turfgrass maintenance programs, but is not often studied by horticulturists. Agricultural engineers have conducted many research studies over the past 50 years on the theory, testing, and use of granular applicators. Understanding the theory of granular distribution can aid horticulturists and turfgrass professionals in the effective use of spreaders. This article will review relevant engineering studies and interpret some of the results to provide help in using spreaders more effectively. Proper operating mode, proper pattern adjustment, and the use of an appropriate swath width can greatly improve pattern uniformity. For instance, a half-width pattern has been proven more effective at pattern improvement than right-angle patterns, and the detrimental effect of humidity on spreader pattern has been demonstrated.
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.
The initial investment of a precision seeder is cost prohibitive to many small vegetable growers. This study was initiated to evaluate the use of a relatively inexpensive bulk seeder to plant cabbage (Brassica oleracea L. Capitata). Cabbage was direct-seeded with a precision seeder or a relatively inexpensive bulk seeder. Treatments with the bulk seeder consisted of blending viable hybrid seed with nonviable, nonhybrid seed at several ratios to reduce hybrid seed cost and optimize plant spacing. Seed ratios represented 10, 20, 30, 40, 50, and 100% viable seed. Pre-thin plant stands of 30 and 40% hybrid seed treatments were similar to precision-seeded plant stands. Average head size was greatest with 10, 20, and 30% hybrid seed ratios. Marketable yields were similar for all hybrid seed ratios except the 10% ratio. Production costs per acre for the precision seeder were between that of the 40 and 50% ratios. Net income for 40% hybrid seed was similar to that of the precision seeder.