Differences in N uptake and fruit quality between organically and conventionally grown greenhouse tomatoes

Abstract

-Soil-bound intensive greenhouse production has been scrutinized for its sustainability due to contamination of ground water by over-fertilization resulting in leaching of nutrients. As environmental guidelines are becoming more restrictive worldwide, and especially in Europe, many greenhouse growers have converted to more sustainable production systems including rockwool culture with recycled water and organic cropping systems in soil. The increase in popularity of organic production systems has amplified the debate whether organically grown produce is healthier than conventional produce. So far, little is known about the variations in fruit quality associated with production systems for greenhouse grown tomatoes. Thus, two organic (organic fertilization with and without straw amendment) and three conventional tomato cropping systems (regular and increased nutrient solution in rockwool and regular fertilization in soil) were compared in order to evaluate differences in nutrient availability and effects on fruit quality over a three-year period. Three modern medium-sized round tomato cultivars and one old cultivar were compared. There were no significant interactions between cropping systems and cultivars, so that main effects of systems and cultivars could be evaluated. Fruit yields in the organic systems were similar to those obtained in the conventional soil-bound system, but 15% lower than in the regular rockwool system, even though nitrogen concentrations in soil were not limiting in any of the production systems. Frequent organic amendments resulted in higher soil NO 2− 3 contents in the organic system without straw than in the other soil-bound systems, indicating that the organic systems were not yet stable in terms of nutrient availability after three years. A fruit quality index, based on the contents of compounds such as lycopene, β-carotene and vitamin C, was similar in all cropping systems. The old cultivar had a significantly higher quality index, but a lower yield than the other cultivars. According to this study, high quality tomatoes can be obtained through proper adjustment of the quantity and the source of nitrogen fertilizers in organic and conventional cropping systems and the use of selected cultivars with a high nutrient use efficiency for organic systems.greenhouse tomato / organic / conventional / nitrogen uptake / xylem sap / fruit quality

Cultivar and Production Effects on Bioactive Polyphenols

“…Similar results were found in terms of contents of quercetin and kaempferol in tomato fruit skins, which were exposed to high concentrations of N and harvested in May (Stewart et al, 2001). These results are supported by Gravel et al (2010). These results are supported by Gravel et al (2010).…”

Soil health indicators and Fusarium wilt suppression in organically and conventionally managed greenhouse soils

“…These results were opposite to results of several field studies (Clark et al, 1998a(Clark et al, ,b, 1999Drinkwater et al, 1995;Poudel et al, 2001). This difference is probably due to the extremely high levels of organic amendments recommended for organic tomato production in Dutch greenhouses, where tomatoes are harvested from May to December and yields can reach 300-500 metric tons/ha (Gravel et al, 2010). High levels of easily available nitrogen sources, especially nitrate, are generally not associated with soil health , and have sometimes been associated with high susceptibility to Fusarium wilt (Woltz and Engelhard, 1973).…”

“…In autumn 2003, an experiment was set up in two identical greenhouse compartments (150 m 2 each) with a similar history of conventional production to compare various systems of greenhouse tomato production, including an organic soil-bound system and a conventional soil-bound system (Gravel et al, 2010). The soil was a sandy soil with the following characteristics at the beginning of the experiment: pH KCl 5.7; organic matter content 9.3%; clay content (particles < 2 mm) 8%; CaCO 3 0.2%.…”

Organic versus conventional tomatoes: Influence on physicochemical parameters, bioactive compounds and sensorial attributes

“…For instance, Cardoso et al (2011) concluded that there was no evidence of nutritional superiority of organically grown fruits (acerola, strawberries and persimmon) regarding vitamin C and carotenoids contents. Also, Gravel et al (2010) found little differences in what concerns to taste and nutritional value of organic and conventionally grown tomatoes in greenhouses.…”