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  • Author or Editor: Cathy Bakker x
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Soil and crop management practices suggest the possibility of sulfur deficiency for cole crops in Southern Ontario. A 3-year study was conducted to evaluate rates of calcium and sulfur on yield of `Huron' late-storage cabbage. Treatments were based on CaSO4 applied at 0, 1000, 2000, and 3000 kg·ha–1 `Novacal' (Ca 27%, S 19%, Mg 2.5%, Dolomex Inc., Portage-du-Fort, Quebec, Canada), a granulated gypsum product. Potassium sulfate and calcium nitrate were used as elemental controls. Potassium and nitrogen levels were balanced with potassium chloride and ammonium nitrate. Phosphorous applications were based on soil analysis. All treatments were applied pre-plant incorporated. This trial was repeated on sand and loam soils typical of soil used for cabbage production in southern Ontario. Applications of sulfur increased yield of cabbage on sand and clay, although the optimum rate varied from year to year. Medium and high rates produced the highest yield in the first year, while low rates were more effective in the second and third seasons. Response of cabbage to calcium varied from year to year. Medium and high rates of calcium increased yield on sand, but had no effect on clay in the first year. Calcium had no effect on yield on either soil type in the second year. However, in the third year, low rates of calcium produced the highest yield on both sand and clay. Although there were no visual symptoms of deficiency, applications of sulfur, and to a lesser extent calcium, increased yield indicating that a `hidden hunger' for these elements may exist on some soils in southern Ontario.

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Fertigation is a promising strategy to improve nitrogen use efficiency, yield, and quality of cabbage (Brassica oleracea var. capitata), but there is a lack of data relevant to growers in Ontario. Field trials were conducted in 2003 and 2004 to determine the optimum rate of water and nitrogen application in terms of yield and quality of `Huron' cabbage. Treatments consisted of combinations of target soil moisture levels (25% to 100% field capacity) and nitrogen fertilizer (0–400 kg·ha-1 N) as dictated by a central rotatable composite design. Nitrogen applications were split with 50% broadcast and incorporated before planting and the remaining split into weekly applications via a trickle irrigation system. Water was applied two to three times per week to bring soil moisture up to the target levels. Maximum marketable yield was reached at a combination of 400 kg·ha-1 N and a soil moisture target of 100% field capacity. Many heads were undersized or undeveloped at low rates of nitrogen. Applications of nitrogen required for high yield and quality can pose a risk of leaching; however, use of fertigation minimizes potential in-season leaching. Estimated total residual nitrogen at harvest ranged from 83–211 kg·ha-1 N, which could have a negative impact on the environment. Thus, there is a considerable challenge to reduce environmental impact without economic losses. Improved knowledge of in-season nitrogen requirements might further reduce the levels of nitrogen applied without reducing yield and quality.

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Globe artichoke (Cynara scolymus L.) is a high value cool season crop which requires vernalization to induce flower formation. The climate in Ontario does not allow for survival of perennial cultivars or for consistent natural vernalization of annuals. Three methods of vernalization were tested: a controlled environment chamber, a lighted cold storage, or GA3 application in the field. Plants, cv. Green Globe Improved, were grown in a greenhouse set at 25 °C day temperature in 72-cell Styro-foam trays in a peat mix. At 4 weeks, plants receiving vernalization were transferred to growth chambers, or lighted coolers (four standard 8 foot cool white fluorescent lamps) at 10 °C for two weeks. The others stayed in the greenhouse. GA3 treatments (PROGIB, 15 g ai/ha) were applied at 2, 4 and 6 weeks after transplanting. Cultivars Green Globe Improved, Imperial Star, Emerald, and Large Green Globe were evaluated in separate trials. Trials were conducted at Simcoe, on coarse sand in a high heat area, and Kettleby, on organic soils in a cooler area of Ontario. Shortly after planting at Simcoe several 30 °C days occurred which devernalized and injured the crop. Artichokes grew well at the Kettleby site. Vernalization in the growth chamber was most effective and resulted in the earliest bud formation and highest total yield (1503 cases/ha). Large Green Globe was not well adapted to Ontario conditions. Imperial Star and Emerald produced the highest yields, 2180 and 1779 cases/ha, respectively. Globe artichokes can be grown successfully as an annual crop in cool production areas of Ontario.

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Chives, (Allium schoenoprasum) consumption and production are increasing in Ontario. Rust (Puccinia allii F. Rudolphi) has been a problem with some chive cultivars for some growers, and in Ontario, basic information on production is nonexistent. The objectives were to identify cultivars with high yields, disease resistance and winter survivability. Plantings of six cultivars of chives were established in 2002 and 2003 in two contrasting environments, on organic (Kettleby) and mineral (Simcoe) soils; and one cultivar of garlic chives (A. tuberosum) at Kettleby. Leaves were harvested to a length of 30 cm, weighed and assessed for visible signs of rust. In Spring 2003, the number of dead plants was recorded to determine the overwinter survivability of each cultivar. Performance varied among cultivars and between locations. In Simcoe, Staro produced the highest yield in 2002 while generic (unnamed) chives produced the highest yield in the second year. In Kettleby, yield was similar among cultivars in 2002 but in 2003 generic chives produced the highest yield. Overwinter survival also varied between locations and second season yields were much higher in Kettleby. Less snow cover and subsequent winter injury is a possible explanation for the lower yields and poorer winter survival in Simcoe. No symptoms of rust were found in either location. Chives are a viable crop in Ontario, and appear to have different adaptability to regional soils and climates.

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