Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Frank Stonaker x
  • Refine by Access: All x
Clear All Modify Search
Free access

Debra Guenther and Frank Stonaker

The Specialty Crops Program at Colorado State University conducted research of hardneck garlic (Allium sativum ophioscorodon) production on certified organic land at the Horticulture Field Research Center northeast of Fort Collins, Colo., during the garlic growing seasons of 2002–03 and 2003–04. Winter mulches and irrigation treatments were studied during the first season. It was found that garlic that was covered by any type of winter mulch (grass hay, single or double layers of floating row cover) resulted in better yields (higher average bulb weight) than garlic which was not covered at all (ANOVA, F = 2.93, P = 0.034). Yields from sprinkler and furrow irrigation were essentially the same; however, furrow irrigation used nearly 30% more water. Too little water was applied to the drip-irrigated treatment and yield suffered. Our findings suggest that yields are negatively impacted when less than 12 inches of combined precipitation and irrigation are received. During the second season, clove planting spacings of 3, 4.5, and 6 inches, and flame weeding and scape removal effects on yields were studied. The bulbs that grew at a 6-inch spacing were significantly larger than those grown at 3 and 4.5 inches (ANOVA, F = 46.5, P < 0.001). Flame weeding had no significant effects on yields (t-test, P = 0.6) and may be more economical compared to hand weeding depending on fuel costs. Removing the scapes did result in slightly higher bulb weights (t-test, P = 0.06). Removing scapes takes extra labor and may not be worth the time for only slightly higher bulb weights; however, selling the edible scapes may offset the cost and generate extra income.

Free access

Karen Salandanan, Marisa Bunning, Frank Stonaker, Oktay Külen, Patricia Kendall, and Cecil Stushnoff

Antioxidant properties and quality attributes were evaluated for 10 melon (Cucumis melo L.) cultivars grown under conventional and certified organic conditions in a 2-year field study. Differences among cultivars, produced either by conventional or organic methods, contributed the largest sources of variation in antioxidant properties. A 2.1- to 2.2-fold difference was seen between groups of cultivars with the highest and lowest levels of ascorbic acid when produced by organic and conventional methods, respectively. Choice of cultivar using conventional and organic production, respectively, enabled a 1.7- and 1.6-fold gain in total phenolics, a 2.6- and 4.2-fold gain in radical scavenging capacity determined by 2, 2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid), and a 1.8- and 2.4-fold gain determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Based on an antioxidant index, cultivars with the highest antioxidant properties were Savor, Sweetie #6, Early Queen, Edonis, and Rayan. Organic melons had significantly higher ascorbic acid over both years, whereas total phenolics content was higher only in the first year. Percent dry matter and soluble solids content also varied widely among cultivars but were unaffected by production system. Choice of cultivar provides a viable option for growers interested in producing melons with high antioxidant properties. Cultivars with high antioxidant levels may provide a competitive marketing and supply niche for producers, but the full extent of diversity for antioxidant attributes requires further evaluation of cultivars and germplasm.