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Book of Abstracts

11th IFOAM
Scientific Conference
11-15 August 1996
Copenhagen, Denmark

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Carrot quality: The effect of organic and conventional farming S23

Minnaar, Lizot.

GRAB (Groupe de Recherche en Agriculture Biologique) BP 122284911 Avignon cd9

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The quality of organic produce is of main interest to organic producers, distributers and consumers. The aim of this projectis to study the differences between organic and conventional carrots (Daucus carota L.).

Twelve farmers (organic/conventionnal) were paired in 1994 and1995 in the south east (Avignon) and south west (Agen) of France. 3 pairs per year, per location were chosen according to the following criteria: same geographical area, same type of soil, same variety, same growing period. Agricultural parameters bearing an influence on crop quality were measured during the growing period. At harvest a large range of quality evaluation methods were used: pesticides and heavy metal content, nutritionnal and sensory properties, holistic methods.

Data of the crop observation show that carrot density and the phosphorus soil content were higher in conventional farming. At different stages of growth the organic carrots were bigger because of the lower density. Yield was not significantly different.

For most of the studied variables, agricultural practices interacted with year and/or location. Pesticide residues were found in 9 of the 12 conventional samples analysed and in 1 of the 12 organic samples. Heavy metal contents were similar. Calcium, phosphorus and boron content were higher in organic carrots. Results show tendance with regard to dry matter content being higher in conventional samples. Other analytical analysis and sensory analysis show no differences. Biophotonic results differed on location (SE-SW). Copper chloride cristallisation results differed firstly between location and secondly between agricultural practices (organic/conventional). Results of food preference tests and P-values are respectively presented in the abstract of Plochberger/Velimirov and Walz.

Organic carrots have the same or better nutritionnal value than conventionnal one. A better phosphorus assimilation is observed which can be explained by a better soil activity (mycorhization). A field trial is however necessary to control the effect of density on quality. The different quality evaluation methods proved to be complementry in this experiment.

Lairon, D., Termine, E., Lafont, H., (1984) Valeur nutritionnelle comparée des légumes obtenus par les méthodes de l'agriculture biologique ou de l'agriculture conventionnelle -Cah. Nutr. Diét., 19 (6), pp 331-339.

Lieblein, G. (1993) Quality and yield of carrots: effects of composted manure and mineral fertilizer - Norges Landbrukshogskole, Agricultural University of Norway, Doctorscientarium theses.

Villeneuve, F., Leteinturier, J. (1992) La carotte, état des connaissance - Edition Ctifl, 227 p.