A Comparison of Four Processing Tomato Production Systems Differing in Cover Crop and Chemical Inputs

Four tomato production systems were compared at Columbus and Fremont, Ohio: 1) a conventional system; 2) an integrated system [a fall-planted cover-crop mixture of hairy vetch (Vicia villosa Roth.), rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), and barley (Hordeum vulgare L.) killed before tomato planting and left as mulch, and reduced chemical inputs]; 3) an organic system (with cover-crop mixture and no synthetic chemical inputs); and (4) a noinput system (with cover-crop mixture and no additional management or inputs). Nitrogen in the cover-crop mixture above-ground biomass was 220 kg·ha–1 in Columbus and 360 kg·ha in Fremont. Mulch systems (with cover-crop mixture on the bed surface) had higher soil moisture levels and reduced soil maximum temperatures relative to the conventional system. Overall, the cover-crop mulch suppressed weeds as well as herbicide plots, and no additional weed control was needed during the season. There were no differences in the frequency of scouted insect pests or diseases among the treatments. The number of tomato fruit and flower clusters for the conventional system was higher early in the season. In Fremont, the plants in the conventional system had accumulated more dry matter 5 weeks after transplanting. Yield of red fruit was similar for all systems at Columbus, but the conventional system yielded higher than the other three systems in Fremont. In Columbus, there were no differences in economic return above variable costs among systems. In Fremont, the conventional systems had the highest return above variable costs. Ecological problems associated with conventional agricultural practices include soil erosion, contamination of water and soil resources with pesticides and nitrates, and an overdependence on fossil fuel (National Research Council, 1989). Thus, there is interest in developing agricultural systems that rely less on fossilfuel based inputs and more on biological processes to achieve similar productivity. Winter annual cover crops can enhance biological processes and potentially reduce fossil-fuel based inputs. They are seeded in late summer or early fall, overwinter, and then resume rapid growth in the spring. Winter annual cover crops can be an important source of biologically fixed nitrogen (Hoyt and Hargrove, 1986), help control soil erosion (Flach, 1990), improve soil physical properties (McVay et al., 1989), reduce nitrate leaching losses (Stivers and Shennan, 1989), add organic matter to the soil (Blevins et al., 1977), influence pest life cycles (Phatak et al., 1990), and suppress weeds (Teasdale, 1993). One method of managing winter cover crops in the spring is to kill them and leave their residue as a surface mulch. The subseOC. HORT. SCI. 121(3):559–568. 1996. or publication 12 July 1995. Accepted for publication 19 Jan. 1996. icle no. 185-95, Ohio Agricultural Research and Development Center, Univ. This paper is a portion of a thesis submitted by Nancy Creamer ulfillment of PhD requirements at Ohio State Univ. This research was in part by grants from the USDA Sustainable Agriculture Research and Program, the Mid-America Food Processors Association, and Virginia We extend our appreciation to Mac Riedel and Debbie Hamner, who th disease assessment, and to Barry Plassman, Randall Wood, and the Univ. Agricultural Engineering Dept. for contributing to the design and n of the undercutter. Mention of a trademark, proprietary product, or s not constitute a product guarantee or warranty by Ohio State Univ. and ply its approval to the exclusion of other products or vendors. The cost ng this paper was defrayed in part by the payment of page charges. Under lations, this paper therefore must be hereby marked advertisement solely