A study was conducted from 1989 to 1991 to examine the effects of continuous tomato cropping, short-term crop rotation and, nitrogen fertilization rates on processing tomato quality. Research was conducted at two sites in southwestern Ontario, Leamington and Dresden, in split-plot experimental design. The rotations included tomato (Lycopersicon esculentum) - winter wheat (Triticum aestivum) (underseeded with red clover (Trifolium pratense), tomato-winter wheat-soybean (Glycine max), tomato-alfalfa (Medicago sativa), and tomato-rye (Secale cereale). Nitrogen fertilization rates of 0, 45, 90 and 135 kg/ha were used. Processing tomato cv. Heniz 9230 and Nabisco Brands Ltd. 7107 were assessed for colour, % soluble solids and total solids, and blossom end rot [BER]. In most instances, continuous tomato [C-T] had significantly poorer colour, soluble solids, and total solids than fruit from the various crop rotations. High nitrogen rates for C-T at Leamington, resulted in improved soluble solids and total solids, but had no significant effect on colour. A lower incidence of BER consistently occurred with low rates of nitrogen. Our results indicate that short-term crop rotation and nitrogen management in processing tomatoes can enhance fruit quality when compared to C-T.
John Seliga, Vernon Shattuck and Russel Johnston
Russell Johnston, Vernon Shattuck and John Seliga
The influence of various crop rotations on the marketable yield of processing tomatoes (Lvcopersicon esculentum) in southwestern Ontario was investigated. The study was conducted for three years using nine and eight crop rotations at Leamington and Dresden, respectively. Four rates of nitrogen, 0, 45, 90, and 135 kg/ha were applied to each rotation. The treatments were arranged in a split-plot experimental design. Tomato yields were generally higher at both locations for all rotations compared to continuously grown tomatoes (control). The highest yields were obtained when tomatoes were grown in an alfalfa (Medicago sativa) rotation and rotations involving rye (Secale cereale) or winter wheat (Triticum aestivum). Tomato yields from the soybean (Glycine max) rotation and from continuously grown tomatoes were similar. At both locations, yields from continuously grown tomatoes increased with increasing rates of nitrogen fertilizer. Optimal yields for each rotation varied with each individual rate of nitrogen. Tomatoes grown in the alfalfa rotation showed the least response to higher rates of applied nitrogen. Our data indicates that certain crop rotations and nitrogen fertilization rates can be used together to enhance the yield of processing tomatoes.
G. Bélair and L.E. Parent
The influence of various crop rotations on population densities of Meloidogyne hapla, the northern root-knot nematode, and subsequent carrot yields was studied in organic soil under field conditions. Seven 3-year sequences with barley (Hordeum vulgare L.), carrot (Daucus carota L.), onion (Allium cepa L.), or weedy fallow, all with carrot as the third-year crop, were replicated six times in a completely randomized block design. Carrot monoculture, two seasons of weedy fallow, or carrot followed by onion resulted in high M. hapla population densities and severe root damage on carrot the third year. Barley followed by onion or onion followed by barley harbored low M. hapla population densities and provided the highest yields, with 56.8 and 47.2 t marketable carrots/ha, respectively, compared to 2.2 t·ha–1 in the carrot monoculture. A single crop of barley reduced nematode population densities and provided 88% and 73% marketable carrot roots in the subsequent years. High M. hapla population densities and the high proportion of culls recorded in plots in weed fallow emphasize the importance of an effective weed management program for successfully using crop rotation against root-knot nematode in muck-grown carrot.
Kathryn E. Brunson, Sharad C. Phatak, J. Danny Gay and Donald R. Summer
Velvetbean (Mucuna deeringiana L.) was used in crop rotation to determine the influence on southern root-knot nematode (Meloidogyne incognita) in sustainable vegetable production. Replicated trials were conducted at four locations. Two cover crop treatments, crimson clover and subterranean clover, were used in the sustainable plots and rye was the plow-down cover crop for the conventional plots. Selected as the vegetable crops were tomato, pepper, and eggplant. Following the final harvest, velvetbean was planted into the sustainable plots and disked under after 90 days. Results from soil samples before and after velvetbean, indicated the sustainable plots had substantially reduced nematode densities, while most conventional plots showed increases. A correlation between location, treatment, root-gall indexes and nematode density occurred in all crops for 1992. In 1993 there was only a correlation between root-gall index and nematode density in pepper. However, root-gall indexes were significant for location and treatment in all crops.
John Speese III and S.B. Sterrett
The effect of crop rotation was investigated on the efficacy and the economics of various insecticide strategies for Colorado potato beetle (CPB) control in potatoes (Solanum tuberosum L.) in 1995-96. These included broad-spectrum insecticides and biorational (environmentally friendly, naturally occurring) combinations that targeted specific CPB life stages. CPB pressure was greater in the nonrotated than the rotated plots. Although all materials gave better CPB control than the check, significantly more spray applications were required to reduce CPB numbers below treatment thresholds in the nonrotated plots than the rotated plots in both years. Overall yields and economic returns were significantly greater in the rotated plots in 1995. Efficacy of insecticide strategies varied, with little defoliation and few CPB larvae found in the imidacloprid treatment in 1995 and 1996. All insecticide strategies except endosulfan resulted in significantly higher estimated returns to management than the untreated check; the greatest returns occurred with permethrin and cryolite. No yields or returns could be obtained in 1996 due to excessive rainfall before harvest. These results indicate that yield and the cost of the insecticide strategy should be considered as well as insecticide efficacy in developing an effective integrated pest management program.
Kathryn E. Brunson, Sharad C. Phatak, J. Danny Gay and Donald R. Sumner
Velvetbean (Mucuna deeringiana L.) has been used as part of the crop rotation in low-input vegetable production in southern Georgia to help suppress populations of root-knot nematode (Meloidogyne incognita) for the past 2 years. Over-wintering cover crops of crimson and subterranean clovers were used the low-input plots and rye was the plow-down cover crop in the conventional plots. Tomatoes, peppers, and eggplant were the vegetable crops grown in these production systems. Following the final harvest in 1992, use of nematicides in the low-input plots was discontinued and velvetbean was then planted into the low-input plots and disked in after 90 days. Results from the 1993–94 soil samples taken before and after velvetbean showed a continuing trend of reduced nematode numbers where velvetbean had been, while most conventional plots that had nematicides applied resulted in increases in nematode populations.
J. Alvarez, L.E. Datnoff and R.T. Nagata
The severity of corky root disease (Rhizomonas suberifaciens Van Bruggen et al.) increases with continuous lettuce (Lactuca sativa L.) cropping and exerts a negative impact on the quantity and quality of the lettuce produced. Experimental data from commercial fields were used to analyze profitability outcomes resulting from various management strategies, including cultivars, locations, and field cropping history, to control corky root. Regardless of the field cropping history, net returns were not negatively affected when resistant cultivars were planted. For susceptible cultivars, even when considering land development costs, producers maximize net returns by planting lettuce following sugarcane in land not previously cropped to lettuce. After the first crop of lettuce following sugarcane, yields slowly decreased but remained profitable for three to four crop cycles.
Ann Toren Seigies and Marvin Pritts
In July 2001, a study was established in a field with a 30-year history of perennial strawberry production to examine effects on replant disorder of 12 different species of preplant cover crops, soil fumigation (methyl bromide plus chloropicrin), and fallow management. In May 2002, strawberries (`Jewel') were planted into pots containing soils with the incorporated cover crops, grown for 1 year, and then fruited. Strawberry yields in 2003 were highest in pots containing indiangrass (Sorghastrum avenaceum) and brown mustard (Brassica juncea) -incorporated soils, resulting in 32% and 28%, respectively, higher yield than plants in pots containing untreated, bare fallow soil. Yield was lowest in fumigated soil or soil incorporated with sunnhemp (Crotolaria juncea), having 19% and 10% less yield than the fallow treatment, respectively. In Aug. 1999, a complementary study was established in a field with a 7-year history of continuous perennial strawberry production to examine the effects of single species and multiple species rotations on replant disorder, bacterial populations, and fungal pathogens over 2 fruiting years. Cover crop treatments included various monocultures and sequences of perennial alfalfa (Medicago sativa), brown mustard, kale (B. oleracea `Winterbor'), sweet corn (Zea mays `Saccharata'), rye (Secale cereale), hairy vetch (Vicia villosa), marigold (Tagetes patula `Nema-gone'), oats (Avena sativa `Newdak'), and sudangrass (Sorghum bicolor × S. sudanese). These rotations were compared with the effects of fumigation using methyl bromide with chloropicrin (99:1), continuous strawberry, and bare fallow. Symptoms of replant disorder developed in the continuous strawberry plots within a few months of planting. Plants in the fumigation treatment produced greater fruit yield than all other treatments in 2003, 139% more than plants from the continuous strawberry treatment. Strawberry plants grown in the kale/sweet corn/rye treatment had consistently high yield, and both the hairy vetch/marigold/rye and the oats/sudangrass/rye treatments led to marked improvement over the continuous strawberry treatment. Plants from the brown mustard treatment also were more vigorous and productive than plants from the continuous strawberry treatment during 2002 despite having relatively low foliar biomass and a relatively high level of fungal infection on strawberry plant roots. In the field, symptoms of replant disorder were best overcome by fumigation with methyl bromide or multiple species rotations, particularly that of kale followed by sweet corn and rye. Although Rhizoctonia levels were associated with poor root health, general fungal and bacterial root infection rates were not consistently associated with the presence of visible symptoms of replant disorder nor with strawberry plant growth and productivity.
K.M. Batal, D.R. Decoteau, D.M. Granberry, B.G. Mullinix, D.C. Sanders, G.D. Hoyt and R.J. Dufault
Pepper and sweet corn were tested in a rotation with crimson clover and velvet bean (Mucuna pruriens) cover crops at different locations in Georgia, North Carolina, and South Carolina from 1995 to 1996. Vegetable production with minimum-till following the cover crops was compared with two different conventional methods (following rye cover or fallow). All minimum-till/cover crop treatments caused reduction of total number of pepper fruit, compared to the conventional methods. Effects on premium grade (Fancy + U.S. #1) were similar to the effects on total fruit. The highest percentage of premium grade was produced by both conventional methods in 1996. Sweet corn responded similarly to these treatments in 1995. However, in 1996, clover plots had corn yields nearly as good as the conventional plots. As in bell pepper, plots with velvet bean cover produced lower yield in 1996. Treatment effects on number of marketable corn were the same as the effects on total ears produced.
Joan R. Davenport and Mary J. Hattendorf
Potatoes (Solanum tuberosum L.) are grown extensively throughout the Pacific northwestern United States as a high value crop in irrigated rotations with other row crops such as wheat (Triticum aestivum L.) and both field and sweet corn (Zea mays L.). Center pivots are the predominant irrigation systems. Soil texture ranges from coarse sands to finer textured silt loams and silts and can vary within one field, particularly in fields with hilly topography. Site specific management is being evaluated as an approach to help to optimize inputs (water, seed, agricultural chemicals) to maintain or enhance yield and reduce potential negative environmental impacts from these farming systems. Currently, variable rate fertilizer application technology and harvest yield monitoring equipment are commercially available for potato. Variable rate seeding and variable rate irrigation water application technologies are developed but not fully commercialized and variable rate pesticide application equipment is in development. At the Irrigated Agricultural Research and Extension Center in Prosser, Wash., we have a team of research scientists, interested individuals from local industry, and other key organizations (e.g. local conservation districts) who are working together to evaluate different site specific technologies, improve the ability to use available tools, and to improve decision-making ability by conducting research both on farm and in research plots.