DIFFERENCES IN DELTA¹⁵N SIGNATURES TO DETERMINE PLANT MATERIAL FROM INTEGRATED OR ORGANIC GREENHOUSE PRODUCTION

There is no clear analytical method to differentiate between organically and integrated produced vegetables.
In integrated greenhouse-production most vegetables are grown soil-less with mineral fertilization, what is prohibited in organic production.
In order to prove the influence of organic and inorganic N-fertilizer to N isotopic composition of plants, a pot-experiment was conducted.
Chinese cabbage (Brassica pekinensis `Nemino`) was grown in pots with mineral-soil as substrate containing little organic N and organic carbon to prevent N turnover.
In organic treatments, the substrates were amended with compost and hornmeal/compost.
Nitrate and ammonium-nitrate fertilizer were used in the mineral treatments.
¹⁵N values of compost and hornmeal are 6‰ while those of nitrate and ammonium nitrate are 1.6‰ and 0.7‰. Plants growing with nitrate and ammonium-nitrate has significantly lower
¹⁵N values with about -1‰ to 1.6‰. Plants growing in compost and hornmeal/compost were enriched in
¹⁵N, up to 10.5‰. Tomatoes cultivated in soil-less and in-soil with mineral and organic fertilization, respectively, were compared. ¹⁵N values were –1‰, 0‰ of hydroponically and 8‰, 11.2‰ from organically cultivated fruits.
Considering these data and other published results, we conclude that isotope ratio mass spectrometry is a suitable method to discriminate organic from integrated produced greenhouse-vegetables.

VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition

M. Georgi, A. Boullenger, S. Voerkelius, W.H. Schnitzler

isotope ratio, organic production, greenhouse, hydroponics, authentication,

https://doi.org/10.17660/ActaHortic.2004.659.96