During the 1970s a mulched gradient concept was adapted by the Florida vegetable industry and the average yield of tomatoes was doubled. Currently, because of potential water restrictions and society's increasing concerns about environmental pollution, a containerized gradient concept is being evaluated. Containers, media and nutrient/water balance are major components being evaluated to maximize water use efficiency and minimize pollution and, at the same time, maintain or increase the existing competitive excellence. Three seasons of results indicate tomato yields equivalent to those produced commercially; water use has averaged 4 liters/plant/day (about 1/5 to 1/10 that used commercially; and leaching, fumigation and plastic mulches have been eliminated. The concept as a sustainable production system is considered commercially feasible.
Laurie E. Drinkwater, Deborah K. Letourneau, Fekede Workneh, Marita Cantwell, Ariena H.C. van Bruggen, and Carol Shennan
Twenty commercial tomato production systems were compared in a multidisciplinary on farm study. The aim was to determine if organic (ORG) and conventional (CNV) systems differed in terms of agronomic criteria or indicators of underlying ecological characteristics. Field level measures of inputs, yields, fruit quality, arthropod abundance and management operations were made. Also, multiple samples within each field were taken to measure soil chemical and physical properties, root pathogen populations, disease incidence, and pest damage levels for multivariate analysis. Management effects on agronomic criteria (yield, fruit quality, pest damage) were small, whereas differences in soil N pools, microbial activity, pathogen populations and arthropod communities between ORG and CNV sites were sufficiently robust to be distinguished from site to site variation. Relationships between management, crop productivity and fruit quality will be discussed.
Gerald Klingaman and G.L. Wheeler
In 1993, the Arkansas poultry industry produced 1.048 billion broilers with a total live weight of 2.54 million metric tons. Depending on the type of processing used, from 30% to 50% of live weight can end up in the waste stream. Three primary waste-stream products are generated by the poultry industry: feather meal, poultry meal, and bone meal. Feather meal contains ≈14% N, poultry meal 11% N, and bone meal 8% N. Byproduct additions were made to tomato, marigold, and impatiens transplants at the rate of 6, 12, 24 and 48 g/10-cm pot. The two highest rates killed plants outright, while the lower rates resulted in some growth reduction when compared to the control. Studies are under way to further evaluate the use of these byproducts in an organic production system for tomatoes and bedding plants.
John M. Ruter
Membrane thermostability of Heritage river birch (Betula nigra L. Heritage) was measured by electrolyte leakage from excised roots of plants grown in pot-in-pot (PIP) and conventional aboveground production systems (CPS). The predicted critical midpoint temperature (Tm) for a 30-min exposure was 54.6 ± 0.2 °C for PIP and 56.2 ± 0.6 °C for CPS plants. Plants grown PIP had a steeper slope through the predicted Tm, suggesting a decreased tolerance to high root-zone temperatures in relation to plants grown aboveground. Since the root systems of Heritage river birch grown PIP are damaged at lower temperatures than plants grown aboveground, growers should prevent exposure of root systems to high temperatures during postproduction handling of plants grown PIP.
Kathryn E. Brunson, C. Robert Stark Jr., Sharad C. Phatak, and Michael E. Wetzstein
Research results are presented from a multi-year study on vegetable production in southern Georgia that compared two low-input production systems to the conventional rye cover crop technology. The low-input systems use beneficial insect principles as a substitute for conventional pesticide controls, but pesticides are used if needed. Preliminary results from the low-input systems using crimson and subterranean clovers indicate that crimson clover produces better yields and can “catch up” to the conventional rye system. The higher yields of the rye technology can be offset by the cost reductions associated with the low-input technologies. Production budgets were developed for 3 years of eggplant and 2 years of fresh-market tomato and bell pepper to reveal expected net returns under the low-input and conventional systems.
Kenneth L. Steffen, Michael S. Dann, Jayson K. Harper, Shelby J. Fleischer, Sizwe S. Mkhize, Doyle W. Grenoble', Alan A. MacNab, Ken Fager, and Joseph M. Russo
During the initial season of implementation, four tomato production systems differing in soil management, pest control practices, and level of inputs, such as labor, materials, and management intensity were evaluated. These systems were CON, a low input (no mulch, no trellising, overhead irrigation, preplant fertilization, scheduled pest control), conventional agrichemical system; BLD, a high input [straw mulch, trellising, trickle irrigation, compost fertility amendment, integrated pest management (IPM)], ecologically-oriented system that emphasized the building up of soil organic matter levels and used no agrichemicals to supply fertility or for pest control; BLD+, a system similar to BLD, except that agrichemical pesticides were used; and ICM, a high input system (black polyethylene mulch, trellising, trickle irrigation, fertigation, IPM pest control) that used agrichemicals to supply fertility and for pest control. Soil characteristics and fertility levels in the BLD and BLD+ systems were modified with extensive amendments of spent mushroom compost and well-rotted cattle manure. Levels of agrichemical NPK calculated to meet current crop needs were supplied to the CON and ICM systems, with 75% of fertility in the ICM system supplied through the trickle irrigation lines (fertigation). The BLD system had a greater soil water holding capacity and sharply reduced irrigation requirements. During a wet period, fruit cracking and evidence of water-mold root rot were significantly higher in the ICM system than the BLD and CON systems. Defoliation by Alternaria solani was greatest in the BLD system and least in the ICM system. The BLD and ICM systems resulted in a 1 week earlier peak yield compared to the CON system. The yield of No. 1 fruit was 55% to 60% greater in the BLD+ system than the other three systems, which were comparable in yield. Net return was highest in the BLD+ system, although the benefit/cost ratio was greatest in the CON system. This multidisciplinary study has identified important differences in the performance of diverse production systems during the unique transitional season.
Charles D. Bornt, J. Brent Loy, William G. Lord, and Otho S. Wells
Research was conducted in New Hampshire during Fall 1995 and Spring 1996 to determine a planting schedule, rowcover type, application time, and plastic mulch type to be used in adapting the annual hill strawberry production system to New England. Treatments in Fall 1995 included two planting dates, three mulch types, and four rowcover modifications. Yields did not differ statistically between a 18 Aug. and 1 Sept. planting date or among plastic mulches. Typar 518 floating rowcovers significantly increased branch crowns, and early and total fruit yield compared to hay mulch applied for winter protection. Research was initiated in Fall 1996 to determine the effect of runner production on yield. Plug plants (50 vs. 24 tray) were treated with different day lengths and temperatures and planted in the field on 26 Aug. or 9 Sept. All plants were covered with Typar 518 on 4 Oct. 1996. Larger, late-planted plugs treated with cool, short days produced no runners in Fall 1996 and increased branch crowns and total yield in Spring 1997. Plants set out in Fall 1995 were evaluated for 2nd year production with or without runner pruning and four rowcover treatments in Fall 1996. Runner pruning did not significantly increase total yields, but resulted in earlier fruit harvesting in Spring 1997. Typar 518 applied 4 Oct. resulted in the greatest yield of any rowcover treatment.
Jens-Norbert Wünsche, Alan N. Lakso, Steven S. Denning, and Terence L. Robinson
A 14-year-old trial of `Empire' apple production systems (Slender Spindle/M9, Central Leaders on M7 and 9/111 interstems, and Y-trellis/M26) had shown significant yield differences that were primarily related to total light interception, but yield of fruit/MJ light interception, however, was still higher in the Y-trellis. The hypothesis tested was that in healthy orchards yields are related primarily tototal light intercepted by the spur canopy. In 1991 seasonal leaf area development, exposed leaf photosynthesis, fruit growth, total light interception (by image analysis of fisheye photos) and relative light interception by different shoot types (by a laser sunbeam simulator) were estimated. The results reflected the mature, spurry nature of these trees. The final LAI values were CL/7=1.8, CL/9/111=2.3, SS/9=2.6 and Y/26=3.6. Exposed leaf photosynthesis showed few differences. Yields of the pyramid forms were 40-42 t/ha while Y-trellis gave 59 t/ha, with similar fruit sizes. Again, yields were primarily related to % total light interception (48-53% for pyramid forms versus 62% for the Y). Laser analyses showed that the Y intercepted more light with the spur canopy than the pyramid forms, supporting the hypothesis. Yields were better correlated with spur canopy LAI and spur canopy light interception than with shoot canopy LAI and light interception.
C. M. Geraldson
The purpose of this study was to evaluate the commerical feasibility of a containerized gradient concept with relevance to water requirement, pollution potential, and production efficiency. Basic components included one-half cu ft of media/plant with 2 plants/rigid plastic container. Phosphorous, liming material and micronutrients were mixed in the media and the N-K was banded on the surface at both ends of the container which was protected by a plastic cover. Intermittent micro-irrigation was used to maintain either a lateral or vertical nutrient/moisture gradient. Variations in the media, the size and shape of the container, and the frequency and time of water applications were included in the evaluations. In the spring of 1991, 65 gallons of water was utilized to produce 22.9 lbs of marketable tomatoes/plant. Leaching was insignificant and the water required on an acre basis was projected as 4.8 acre inches with a 2000 plant population. The results indicate that the containerized gradient concept is potentially feasible as a sustainable production system.
John M. Ruter
A study was conducted with Lagerstroemia indica x fauriei `Acom a' to evaluate methods for reducing rooting-out problems in a PIP production system. The products tested were Biobarrier™, a geotextile fabric impregnated with trifluralin; Root Control'” fabric bag material; and Spin Out™, a commercial formulation of copper hydroxide (7.1%) in latex paint. Biobarrier™ reduced plant height, shoot dry weight, percent root dry weight outside of the planted container and total biomass compared to the non-treated control. For the control, 7.1% of the total root dry weight was found between the holder pot and planted container compared to 0.2% for the Biobarrier™ treatment. When the holder pot and planted container or the planted container and Root Control™ fabric were both treated with Spin Out™, plant height and shoot dry weight were reduced. Spin Out™ reduced root circling on the sidewalls of the planted containers but not on the bottom of the containers. All treatments except the control reduced rooting-out to a degree that allowed for the manual harvesting of the planted container from the holder pot after seven months in the field.