82 COLLOQUIUM 3 Municipal Waste Compost Production and Uses for Horticultural Crops
For centuries horticulturists have attempted to modify the environment in which vegetable crops are grown. A wide variety of techniques, such as glass cloches, hotcaps, cold frames, hotbeds, and various types of glass greenhouses, have been used to extend the production season. The discovery and development of the polyethylene polymer in the late 1930s, and its subsequent introduction in the early 1950s in the form of plastic films, mulches, and drip-irrigation tubing and tape, revolutionized the commercial production of selected vegetable crops and gave rise to a system of production known as plasticulture. Simply defined, plasticulture is a system of growing vegetable crops where significant benefit is derived from using products derived from polyethylene (plastic) polymers. The later discovery of other polymers, such as polyvinyl chloride, polypropylene, and polyesters, and their use in microirrigation systems, pipes, fertigation equipment, filters, fittings and connectors, containers for growing transplants, picking and packaging containers, and row covers further extended the use of plastic components in this production system. The complete plasticulture system consists of plastic and non-plastic components: plastic mulches, drip-irrigation, fertigation/chemigation, soil sanitation (fumigation and solarization), windbreaks, stand establishment technology, season-extension technology, integrated pest management, cropping strategies, and postharvest handling and marketing. In the plasticulture system, plastic-covered greenhouses, plastic mulches, row covers, high tunnels, and windbreaks both permanent and annual are the major contributors to modifying the cropping environment of vegetable crops, thus enhancing crop growth, yield, and quality. In addition to modifying the soil and air temperatures, there are also the benefits of protection from the wind and in some instances rain, insects, diseases, and vertebrate pests.
Abstract
Double-cropping systems were compared to the same vegetable monocropped. Snap beans [Phaseolus vulgaris (L.) ‘Bush Blue Lake’], sweet corn [Zea mays (L.) ‘Sundance’], cauliflower [Brassica oleracea (L.), Botrytis group, ‘Snow Crown’], summer squash [Cucurbita pepo (L.) ‘Zucchini Elite’], and broccoli [Brassica oleracea (L.), Italica group, ‘Green Comet’] were used. The double-crop systems used were spring snap bean and fall cauliflower, summer squash and fall broccoli, and spring sweet corn and fall snap beans. The monocrop system was used as a control for the double-crop systems. The greatest net returns were: 1) squash monocropped or squash/broccoli double-cropped, 2) squash double-cropped, 3) cauliflower or cauliflower/snap bean double-cropped, and 4) broccoli or cauliflower or snap beans monocropped. Fall snap beans provided the least economic return. The double-cropping system allows an option of crop production with a potential increase in yield and economic returns using half the amount of land per year required for either crop grown in monoculture. In addition, these systems reduce the risk of economic failure during a year of low-market demand for either crop grown alone.
A mulch of municipal solid waste compost at 224 t·ha was compared with glyphosate sprays and a nontreated check for weed control in vegetable crop bed alleys during Spring and Summer 1992. In both experiments, there was a significantly lower percentage of weed coverage in the compost mulch and herbicide spray plots than in the control plots. Weed control in the compost and herbicide treatments was similar. In the spring experiment, tractor tire traffic through the alleys reduced weed growth in all plots by 62 % and 44% at 16 and 73 days after treatment initiation, respectively. These results suggest that municipal solid waste compost may have potential as a viable mulch for weed control in vegetable crop alleys. Chemical name used: isopropylamine salt of N -(phosphonomethyl) glycine (glyphosate).
Summer cover crops can improve soil fertility by adding organic matter, supplying nutrients through mineralization, reducing nutrient leaching, and improving soil water and nutrient holding capacity. Other benefits include weed suppression and reduction of soil parasitic nematodes. A series of field experiments have been conducted at the UF IFAS Tropical Research and Education Center in Homestead, Florida to evaluate several summer cover crops for use in vegetable production in South Florida followed by field demonstrations conducted in the growers' fields. Best performing cover crops were legumes: velvet bean (Macuna deeringiana) and sunn hemp (Crotalaria juncea L. `Tropic Sun') providing 13 and 11 Mt of dry matter/ha, respectively. Sunn hemp supplied 330 kg N/ha followed by velvet been with 310 kg N/ha. Traditional summer cover crop sorghum-Sudan produced 4 Mt of dry matter/ha and retained only 36 kg N/ha. In addition Sunn hemp significantly reduced soil parasitic nematodes for successive crops. Limitations in use of Sunn hemp by more vegetable growers in South Florida include cost and availability of seeds.
Greenhouse studies examined the effects of an aquatic herbicide (fluridone) in irrigation water on four vegetable crops growing on two soils. Tests on Fuquay loamy sand (0.3% humic matter) and Portsmouth fine sandy loam (4.1% humic matter) examined fluridone concentrations ≤250 μg·L−1. Injury to sweet corn (Zea may L.), cucumber (Cucumis sativus L.), bell pepper (Capsicum annum L.), and tomato (Lycopersicon esculentum L.) on these soils varied with soil type and stage of plant growth. Seedlings or new transplants were more susceptible to fluridone damage than older plants. All plants showed more injury on Fuquay loamy sand, which had the lowest humic matter content. Injury to cucumber occurred only to seedlings exposed to 250 μg·L−1 on the Fuquay loamy sand. Bell pepper was the most sensitive crop to fluridone. The “no observed effects level” below which no significant injury of a crop occurred over both soil types and both stages of crop maturity was 5 μg·L−1 for sweet corn, bell pepper, and tomato and 100 μg·L−1 for cucumber.
Initiated by DC Sanders, the Southeastern Vegetable Crops Guidelines (SVCG) represents a major regional collaborative effort of Extension Specialists from Alabama, Louisiana, Georgia, Mississippi, North Carolina, and South Carolina whose aim is to produce an annually updated, all-in-one, fits on the dashboard of your truck reference for commercial vegetable growers and Extension workers for the Southeastern US. The first edition was developed in 1998 and published in 1999 as a “for pay” publication, but subsequent editions have employed a partnering with a corporate sponsor and publication company resulting in faster turnaround for printing and a no-cost publication. Each August, a team of Extension Vegetable Specialists, Extension Plant Pathologist, Extension Weed Specialists and Extension Entomologist from around the southeastern US meet for the Southeastern Extension Vegetables Workers (SEVEW) meeting. At this 2-day meeting, the participants' primary focus is to review, rewrite, refine, and update the current year's recommendations for the next edition of the SVCG. Although this publication is mainly used by the states listed, researchers and specialists from other states (FL, KY, OK, VA, TN) annually participate in this meeting. The SEVEW meeting has developed into an opportune forum for dialogues and exchanges updating each other as to the present critical issues in our respective states. Several land-grants are in the process of or are counting the SVCG/SEVEW as part of their federally-mandated multistate programming. Additionally, the SEVCG and SEVEW meeting are officially recognized as a Regional Project by CSREES. The 2005 edition can be found at http://www.aces.edu/dept/com_veg/2005_SEVCG.pdf.
The authors would like to acknowledge D. Bilyea for his expertise and technical assistance in these studies. Funding for this project was provided by the Ontario Fruit and Vegetable Growers Association and Ontario Processing Vegetable
Despite some advantages, adoption of slow-release fertilizers in vegetables has been slow primarily due to cost. In crops fertilized with ground equipment, growers can make fewer trips through the field and assure fertilizer is present when conditions prevent application. With drip irrigation, some materials are difficult to inject, however, Nitamin is a new injectable liquid produced by Georgia Pacific. Thus, with plasticulture, growers can inject less frequently and potentially use lower rates. Granular and liquid formulations of slow-release fertilizer were tested on onions (Winter 2003–04), cabbage (Winter 2003–04) and pepper (Spring 2004) in Georgia. Combinations of traditional fertilizer with slow-release formulations and various rates of slow-release fertilizer alone were compared to a standard fertilizer program on these crops in separate experiments. The slow-release contains only N. So, other nutrients were held constant. Otherwise normal cultural practices were employed. Crops were harvested at maturity and data collected on yield and quality. In cabbage, with at least 50% of the standard N rate using the slow-release fertilizer, yields were comparable to the standard. Results on onions were similar with N rates of at least 75% of the standard for the liquid material; the granular formulation did not perform well. Split applications of slow-release fertilizer and combinations with standard fertilizer worked well for cabbage, but not for onions. Results on pepper, although inconclusive, indicated it was possible to get comparable yields at lower N rates with the slow-release material. Based on these results, lower N rates are possible on cabbage and onions with slow-release fertilizers which may make them economically feasible while providing application advantages to growers.
Overcoming environmental stresses during seedling establishment is crucial to successful vegetable production. In the irrigated production areas of the West stress is most often related to unfavorable temperature, soil or water salinity, or poor soil structure; it is frequently difficult to separate the effects of these stresses since they may all be present to some significant degree. Growers use a variety of techniques to ameliorate these conditions. Advances in seed priming and coating have improved seedling establishment under unfavorable temperatures, particularly for lettuce. The use of sprinkler irrigation for stand establishment has become a widespread practice; sprinkling moderates soil temperature, minimizes salinity in the zone of germination, and reduces soil crusting. By modifying bed configuration growers have been able to increase soil temperature to stimulate germination. Modifying furrow irrigation patterns can create zones of lower salinity. Various chemical treatments have proven effective in reducing soil crusting. The use of transplants is expanding for many crops, both as a means to circumvent seedling establishment problems as well as a technique to obtain earliness.