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  • Author or Editor: Petrus Langenhoven x
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Operational cost of producing lettuce (Lactuca sativa) during the winter in greenhouses is high in the northern regions of the United States due to the addition of supplemental lighting (SL) and heating. Crop productivity in greenhouses should increase to offset high operational costs and maintain profits. Factors including SL composition, heating efficiency, suitability of production systems (PS), and cultivar performance can affect crop productivity. Research-based information on optimizing the above environmental- and production-related factors is limited. This information is critical for growers to make informed decisions and increase profits during winter hydroponic production. We evaluated the interactive effects of SL composition, solution temperature, PS, and cultivar treatments on lettuce shoot dry weight (SDW, g·m−2) and shoot water content (SWC, %) in a greenhouse maintained at suboptimal air temperature (13.7 °C) using a split-plot design. There were three light treatments (sunlight without SL, sunlight + narrow-spectrum SL at nighttime, and sunlight + full-spectrum SL at nighttime), two solution temperature levels [heated (18.8 °C) and unheated (13.2 °C)], two hydroponic PS [constant flood technique (CFT) and nutrient film technique (NFT)], and eight cultivars included in the study. Results indicated that 1) a narrow-spectrum SL at nighttime in combination with heated solution resulted in maximum SDW of lettuce, 2) the SDW and SWC (major determinant of economic yield) increase between the heated and unheated solution temperature treatments was higher in the CFT than in the NFT, and 3) the positive effects of using heated solution were seen mainly in the green-color cultivars. Our research identified the optimal spectral composition of nighttime SL, tested the positive effects of alternate heating methods using heated solution on plant growth under suboptimal air temperature conditions, compared the suitability of two hydroponic PS for lettuce production, and quantified yield potential of several lettuce cultivars in hydroponic production during winter. Growers can use our research findings to make informed decisions about their investment and to maximize hydroponic lettuce productivity and profits during winter.

Open Access

The domestic market for melons, Cucumis melo L., has not been well characterized. The 2011 cantaloupe-related foodborne illness outbreak reduced melon production by 32%, and per capita consumption of cantaloupe and honeydew melons has not recovered. Our objective was to profile and characterize consumer segments of individuals who purchased melons in the 3 months before the survey. Responses from 1718 participants were analyzed by consumption volume and subjected to cluster analysis based on importance of melon attributes. Heavy and moderate consumers preferred local melons over imported. The top four melon attributes were flavor, freshness, ripeness, and sweetness. As consumption increased, consumers placed more importance for their diets. The heaviest consumption group accounted for 22% of the market, and consumed nearly three times the melon servings per month compared with the moderate consumer, and nearly 10 times the servings of the light consumption group. Cluster analysis produced three distinct clusters. Cluster 1 was the most promelon in attitudes and consumption, as well as general health interest, craving sweet food, food pleasure, and variety seeking in foods. The largest segment was cluster 3 and was the ideal group for future targeting of marketing and advertising campaigns for increasing the melon market share with their intermediate consumption and promelon attitudes. Last, members of cluster 2 consumed the lowest amount of melons, spent the least on melons, and traveled the fewest number of miles to purchase them, relative to the other two segments.

Open Access

Healthy transplants are critical to productivity in the field. For certified organic production in the United States, seedlings must be grown in media that meet the standards of the US Department of Agriculture’s National Organic Program. Many commercial organic media options are available, they vary substantially in composition, and it is unknown to what extent this influences seedling performance. This project compared tomato (Solanum lycopersicum L.) seedling emergence and growth in seven commercially available media for organic production and evaluated posttransplant performance. Tomato seedlings were grown in greenhouses at Wanatah, West Lafayette, and Vincennes, IN, USA. Chemical characteristics of the media measured in saturated media extract ranged as follows: pH 5.2–7.5; electrical conductivity (EC) 0.79–4.68 dS·m−1; 1–332 ppm nitrate-nitrogen, 5–69 ppm phosphorus, 41–451 ppm potassium, 78–714 ppm calcium, and 25–121 ppm magnesium. Higher media EC was associated with slower and less uniform seedling emergence and reduced total emergence. Seedling aboveground dry weights were significantly greater in media that contained compost. Relative performance in media containing compost varied across trials. The aboveground dry weight of tomato seedlings 4 weeks after transplanting did not differ for seedlings started in the five compost-based media, and those plants were significantly larger than plants started in the two media without compost. Larger plants tended to flower and set fruit earlier. Media testing protocols that predict nutrient supply over the production cycle could likely improve management in organic transplant production.

Open Access

Before consumers choose what and how much fruit to buy, they first decide where to buy it. To address the choices of stores for fresh fruits, this study investigated the influence of market attributes and customers’ attitudes toward their purchasing decisions. Data from a web-based survey of 1658 U.S. consumers were used to conduct multinomial logit regression to investigate the factors guiding their choices regarding four types of stores: chain, independent, club/warehouse, and direct-to-consumer. We found attitudinal scales and market attributes have different effects on the choice of marketplace for fresh fruits. Driven by price and convenience, most consumers prefer chain stores when buying fresh fruits, whereas those same factors deter them from choosing independent and ethnic stores for fresh fruits. The supply of local fruits, friendly atmosphere, and access to desirable fresh fruits positively influenced consumers to purchase fruits at local markets. Our findings can provide insight regarding food retailers and farmers targeting fresh fruit consumers. For example, our findings highlight the importance of providing a friendly atmosphere and outstanding customer service to positively influence purchasing behavior.

Open Access