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Book of Abstracts

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

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Allelopathic effects of bio-dynamic and organic treatments on wheat and potatoes S29

Deffune, G.; Lee H.C.; Scofield A.M.; Simunek P.

Sustainable Agriculture Research Group and Biological Sciences Department. Wye College, University of London, Wye, Ashford, Kent TN25 5AH, Fax: (01233) 813320, U.K.

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The biodynamic preparations were the first set of treatments used as applied allelopathy in farming systems. In Brazil this method holds potential for the discovery of new sources of active principles.

A PhD research investigates effects of biodynamic and organic systems on yield and quality of wheat and potatoes, using randomized complete block, blind field experiments, with secret codes for samples and treatments: A = control, A+ = NPK and foliar spray, B & C = blind biodynamic & organic. The biodynamic preparations were applied according to standard procedures, matched by mimic treatments.

Crops were cultivated in spring/summer of 1993 & 95 and a rotation with rye/vetch mixture for green manure and weed control in 1994. The biomass was left as mulch in B & C plots and removed from the control plots.

Contrasts of interest show statistically significant differences as follows: Wheat - A vs B & C* and A+ vs B & C* in both grain and biomass yields and quality in terms of Thousand Grain Weight** and baking properties (Hagberg Falling No.*). A+ had higher yield but lower quality. The biodynamic system shows optimal HFN*(249.83) with a lower phosphorus** content than the organic (the highest in P). Other element levels like Ca,K, Na, NO3 and ash do not vary significantly.

Potatoes - A+ vs B & C; yields did not differ in dry weight and A+ potatoes had the lowest dry matter content*** after a 6 month storage period. B & C have also shown better conservation* (less tissue browning). Bvs C; B had a higher amount of tubers 40mm than C.

Significant quality differences between biodynamic and organic treatments indicate the presence of allelopathic stimulation by the biodynamic preparations. Much higher soil nitrate levels in the positive control A+ plots did not increase proportionally the yields, but significantly relate to lower quality in both wheat and potatoes.

Almeida, F.S. (1988). A alelopatia e as plantas. Circular no53, IAPAR, Parana, Brazil, 60 p.

Deffune, G. 1990. MSc Dissertation, Wye College, 1-28.

Koepf, H.H. et al., 1976. Bio-dynamic Agriculture: an introduction, 4: 206-224.