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William B. Evans and Margaret McMahon

There is significant interest in using non-chemical methods to control seedling height in vegetable transplant production. One method being evaluated is the use of greenhouse films that filter signifcant amounts of far-red light from ambient light, resulting in shorter tranplants. This study was undertaken to evaluate fruit yield and quality of field-grown tomatoes produced from seedlings grown under light-filtering plastics. Tomato seedlings were grown under clear polyethylene tents or light-filtering laminate tents in a polyethylene-covered Quonset greenhouse in northern Ohio. Standard 288 deep plug trays, filled with MetroMix 360, were used. Seedlings were placed under the tents at the cotyledon stage and transplanted 28 days later. Once in the field, they were grown as staked plants under open conditions using locally accepted horticultural practices. Differences in seedling height were detected within a few days after being placed under the tents. Compared to those grown under clear polyethylene tents, seedlings grown under the light-filtering plastic increased in height more slowly and were shorter at transplanting. At harvest, within each of the three cultivars tested, no significant differences in fruit number, yield, or mean fruit size were found between treatments. It is inferred that this non-chemical method for reducing vegetable transplant height may be a viable production option in the future.

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William B. Evans and Darryl D. Warncke

Six potato cultivars (Atlantic, Sebago, Onaway, Russet Burbank, Lemhi Russet,and Norland) were evaluated for phosphorus uptake efficiency in solution culture. Individual rooted cuttings of each cultivar were transferred from a standard 1/5 Hoagland's solution into solutions containing one of six P concentrations (0.05,0.1,0.22,0.5,1.1 and 2.3mg/l). After a 24h adjustment period P uptake was followed over a 6h period by collecting solution aliquots every two hours. All cultivars depleted the two lowest initial P concentrations to similar stable P concentration. The P uptake rate per unit length of root showed a sigmoidal relationship to the initial P solution concentration. The general nature of the P uptake relation to solution P concentration was similar among the cultivars, although the actual values varied. In general, P uptake rate increased from 5.0 × 10-4 at the lowest concentration to 7.0 × 10-2μg·cm-1·h-1 at the highest P solution concentration.

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Darryl D. Warncke and William B. Evans

Phosphorus applications can increase potato yields in Michigan soils with over 400 kg·ha-1 Bray-Kurtz P1 extractable P. Four potato cultivars (Onaway (On), Kennebec (Ke), Russet Norkotah (RN), and Snowden (Sn)) were planted on 7 May 1993 to study P fertilizer effects on root growth and development. Each plot received adequate N & K, and either 0 or 50 kg·ha-1 P. Two minirhizotrons (5 cm i.d.) were set 1.1 m deep at 45° to the soil surface into each plot. P treatment did not influence tuber yield. At 65 days after planting, root counts for On, RN and Sn averaged 72, 44 and 58%. respectively, of those in Ke plots. The P treatment did not significantly influence total root counts within or across cultivars on any of five sampling dates. More visible roots were produced in the first 0.4 m of soil by plants receiving P than by plants not receiving P. Below the first 0.4 m, plants not fertilized with P produced more visible roots than those receiving P.

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William B. Evans and Mark A. Bennett

A significant portion of the Great Lakes region's processing tomato crop is used to make whole fruit and diced products, where fruit color and textural uniformity are important. Soil and fertilizer studies were undertaken to better understand the role of soil fertility and potassium application on the color disorder known as internal white tissue (IWT) under this region's conditions and in area soils. During 2 years of replicated potassium rate trials in Ohio, tomato yield was not significantly altered by broadcast potassium applications. Potassium application rate was inversely correlated with frequency and severity of IWT in each season, and positively correlated with titratable acidity. The ability of split applications to influence IWT severity was not significantly different than that of preplant applications. IWT symptom frequency and severity was correlated with elemental concentrations in the fruit, leaves, and soil. In 1998, severity of IWT symptoms was positively correlated with shoulder tissue calcium and sodium concentrations, and negatively correlated with concentrations of phosphorus, magnesium, and nitrogen. Correlations for other nutrients, including potassium, were less clear. A companion study of six grower fields during the second year, using grid sampling techniques and the IWT-susceptible Peto 696 cultivar, found significant variability of IWT symptoms within and among fields. Variability within fields was correlated with soil nutrient concentrations. These data indicate researchers may be able to develop recommendations for field mapping and precision management strategies that can reduce the levels of IWT for area growers.

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William B. Evans, Peter M. Hudson, and Keri L. Paridon

In 2005, fifteen southernpea (Vigna unguiculata L.) Walp. subsp. unguiculata (L.) cultivars were evaluated for yield and quality at Crystal Springs, Miss. Pods were hand-harvested at the green-shell stage on three dates in August and early September 2005. In-shell fresh weights, shelled seed weight, and percent shell-out were recorded. Data was compared with that from similar trials in 2003 and 2004. Little disease or insect pressure has been seen in any year. Most peas evaluated have been in the pink-eye class. In 2005, all pink-eye types produced statistically similar fresh seed yield. Top Pick Brown Crowder produced higher seed yield than all other entries. Cream peas tested were generally lower yielding than the pink-eye types, with the lone black-eye cultivar tested, California Blackeye No. 5, intermediate in seed yield. Weighted average days to midharvest was not different among pink-eye cultivars evaluated but was slightly longer for several cream entries and for California Blackeye No. 5. Percent shell-out was highest in Top Pick Brown Crowder and lowest in Mississippi Cream. Over 3 years, more than thirty cultivars have been evaluated in the trials. Overall, most peas within a seed type have produced similar yields with few exceptions. Some lodging of the top-setting peas has been seen. The top-setting peas may offer advantages of ease of picking for hand-harvest in pick-your-own, small farm, and home garden situations. This trial does not address performance for machine harvest.

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Keri L. Paridon, Norman Winter, William B. Evans, and Guihong Bi

Landscape trials were conducted to evaluate 235 cultivars within 66 species in central Mississippi. All entries were grown from seed or vegetatively propagated material. Raised landscape beds were prepared using accepted regional methods. Planting into beds began on 4 April and was completed on 20 April. Plants were given an overall rating based on insect resistance, disease resistance, vigor, flowering, and foliage color. Each cultivar was rated bimonthly until early August when pruning or termination was necessary, depending on each cultivar, at which time rating frequency became once a month through the first freeze. The rating range was 0 to 5, where 5 is optimum and 0 is death. Height (cm) was measured for each cultivar at the same intervals as performance ratings. Heights were recorded to show the average height of each cultivar. No herbicides were applied; handweeding controlled weeds. No insecticides were applied to plants with the exception of the hibiscus where there was severe pressure from sawfly larva. In 2005 central Mississippi experienced a very hot and dry summer. Strong winds and heavy rains in late August and early September associated with Hurricanes Katrina and Rita took their toll on the trial, especially many of the taller cultivars. The top performing cultivars for 2005 were `Intensia Lilac Rose' phlox (Phlox ×), Proven Winners; `Intensia Neon Pink' phlox (Phlox ×), Proven Winners; `Elliottii Wind Dancer' grass (Eragrostis curvula), Pan American Seed; `Intensia Lavender Glow' phlox (Phlox ×), Proven Winners; `Dolce Licorice' heuchera (Heuchera ×), Proven Winners; `Diamond Frost' euphorbia (Euphorbia ×), Proven Winners; `Gold Flake' mecardonia (Mecardonia ×), Proven Winners; `Titan Polka Dot' annual vinca (Catharanthus roseus), Ball Seed; `Sun Fan' scaevola (Scaevola aemula), Proven Winners; `Golden Delicious' salvia (Salvia elegans), Proven Winners.

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Guihong Bi, William B. Evans, James M. Spiers, and Anthony L. Witcher

Two experiments were conducted to evaluate the growth and flowering responses of greenhouse-grown French marigold (Tagetes patula L. ‘Janie Deep Orange’) to two non-composted broiler chicken litter-based organic fertilizers, 4-2-2 and 3-3-3, and one commonly used synthetic controlled-release fertilizer, 14-14-14. In both experiments, fertilizer 4-2-2 was applied at four rates of 1%, 2%, 4%, and 6% (by volume); 3-3-3 was applied at four rates of 1.34%, 2.67%, 5.34%, and 8.0% (by volume); and 14-14-14 was applied at rates of 0.99, 1.98, 3.96, and 5.94 kg·m−3. In general, substrate containing different rates and types of fertilizers had a pH within the recommended range of 5.0 to 6.5. Electrical conductivity (EC) was similar among substrates containing different rates of 14-14-14; however, EC increased with increasing fertilizer rate for substrates containing 4-2-2 and 3-3-3. Substrate EC within each treatment was generally higher earlier in the experiment. For the fertilizer rates used in these two experiments, increasing 14-14-14 fertilizer rate increased plant growth and flowering performance. However, low to intermediate rates of 4-2-2 and 3-3-3 in general produced the highest plant growth index, shoot dry weight, number of flowers per plant, total flower dry weight, and root rating. Plants grown at high rates of 4-2-2 and 3-3-3 showed symptoms associated with excessive fertilization. Plant tissue nitrogen (N), phosphorus (P), and potassium (K) concentrations increased linearly or quadratically with increasing fertilizer rates for all three fertilizers. In general, plants receiving 4-2-2 and 3-3-3 had higher concentrations of N, P, and K than plants receiving 14-14-14. Results from this study indicated that broiler litter-based 4-2-2 and 3-3-3 have the potential to be used as organic fertilizer sources for container production of marigolds in greenhouses. However, growers need to be cautious with the rate applied. Because different crops may respond differently to these natural fertilizers, it is important for growers to test any new fertilizers before incorporating them into their production practices.

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William B. Evans, Kenneth W. Hood, Peter M. Hudson, and Keri L. Paridon

Yield and economics of vegetable crops are being evaluated in non-adjacent organic (OG) and nonorganic (NOG) vegetable production field areas in Crystal Springs, Mississippi. Each production area has six sections in which crops are rotated over several seasons and years. Production techniques and management are as similar in timing and methodology as possible between the systems without compromising either system. Production methods, timing, and costs are recorded for each operation. These are combined with yield data to create budgets and estimated returns for each production system/crop combination. When possible, harvested produce is marketed by a cooperating grower-retailer at a local mid- to up-scale farmers market. Three years into the study, positive returns have been found for several crops including potato (Solanum tuberosum L.), lettuce (Latuca sativa L.), summer squash (Cucurbita pepo L.), cucumber (Cucumis sativa L.), and others. Marketable new potato yields in 2005 were under 10,000 lb/acre for Yukon Gold and Red Lasoda in either production system. Estimated net returns, based on an actual $2.00/lb market price, were positive for all system/cultivar combinations although final budget numbers are not firm. Significant differences in yield among cultivars were seen in potato, lettuce, summer squash, and cucumber. Organic production budgets for other crops in the study are also being developed.

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William B. Evans, Christine E. Coker, Kent E. Cushman, Thomas E. Horgan, and Keri L. Paridon

Three years of trials in Mississippi have led to the naming of a Mississippi Medallion vegetable award winner for 2007, the fourth vegetable winner in the program's history. The Medallion program looks for garden crops that will perform throughout the state of Mississippi and help improve sales of plant materials to gardeners at retail. The Medallion selection process illustrates how growers and marketers, not just gardeners, can select specialty vegetables and cultivars for production and sale. Between 2003 and 2005, the Mississippi Medallion trials evaluated 11 sweet peppers with no green fruit stage for ornamental and yield value. Each site had three or four replications of all cultivars under evaluation annually with four plants per plot set out on raised beds with drip irrigation. Objective evaluation included total yield, marketable yield, fruit size, and days to harvest. Subjective evaluation included crop uniformity, pest tolerance, and appearance of the fruit based on color, uniformity, and shape. After nine trials, four cultivars were among the highest-yielding group in most trials: Mavras, Tequilla, Blushing Beauty, and Gypsy. The Medallion winner, to be announced in Fall 2006, was selected in part because it was within or near the top-yielding group, by least significant difference, in most trials. The perceived attractiveness of the mature fruit to the evaluating team and the perceived potential marketability of the cultivar moved it above the others under consideration. The reasons for not selecting other cultivars as the winner are as important as the reasons for selecting the winning cultivar. In the Medallion pepper case, these were mostly marketability concerns with the other cultivars, not yield issues, relative to that of the winner.

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William B. Evans, Kenneth W. Hood, Keri L. Paridon, and Peter M. Hudson

Yield, input, and economic data from research plots in central Mississippi are being used to test the economic potential of organic vegetable crop production. A six-part, multi-year rotation, including winter and summer cover crops, has been set up to generate yield, cost, and economic return data from vegetables produced in Mississippi using methods allowed by the U.S. Dept. of Agriculture National Organic Standards and accepted by local growers employing pesticide-free and other similar management methods. Data being collected include labor and input costs, yields, and market prices for harvested crops. Marketable produce is being sold through a grower-retailer at a farmer's market. During 2004, the first full year of the rotation, 10 vegetable species were included in the plots. Pest pressure has generally been minimal. With one exception [one of two potato (Solanum tuberosum) cultivars failed to produce a good stand], all crops planted have produced fair to excellent yields. Crops generating high retail prices in this study include potatoes, snap beans (Phaseolus vulgaris), and leaf lettuce (Lactuca sativa). In the future, the yield and price data being generated will be combined with new and existing cost data to create enterprise and production budgets for use by perspective and existing organic vegetable growers.