Managing traditional and soilless culture systems to produce corn salad (Valerianella olitoria) with low nitrate content and lasting postharvest shelf-life
2004
Fontana, E. | Nicola, S. | Hoeberechts, J. | Saglietti, D. | Piovano, G.
Corn salad is traditionally cultivated in soil and commercialized as ready-to-eat produce. Soilless culture system (SCS) allows clean leaf production, easing and shortening postharvest handling in process industries, and to control growth factors. A comparison between the traditional culture system (TCS) and a SCS was conducted, with two plant densities (1067 and 2134 plants/m2). TCS was simulated in polystyrene trays filled with local soil and peat (1:1 v/v), overhead irrigation, and weekly fertilization. Forty-cell trays for SCS, filled with 1:1 perlite and peat, were floated in a nutrient solution. At harvesting plants were packaged and refrigerated for postharvest shelf-life (8 days) evaluations. After 40 days, plants from SCS were marketable. Production was significantly influenced by culture system x plant density interactions. Greater yield was obtained in SCS, particularly with high plant density (1668 g m-2). Reduced leaf nitrate content was obtained in both systems, reaching 132 and 333 mg kg-1 f.w. with TCS and SCS, respectively; these values were below the 2500 mg kg-1 acceptable threshold. During shelf-life, leaf weight loss was ca 1% and not affected by cultural techniques. SCS produced high quality marketable plants in 40 days, with low nitrate content, while TCS required an extended growing period.
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