ifoam'96 ifoam'96
Book of Abstracts
11th IFOAM Scientific Conference
11-15 August 1996, Copenhagen, Denmark
EcoWeb Denmark


Humic Acids and Three Bio-Dynamic Preparations. P1; 19

Deffune, G. & Scofield, A. M.

Sustainable Agriculture Research Group and Biol. Sciences Dept., Wye College, Wye, Ashford, Kent TN25 5AH, U.K.

Allelopathic effects are biochemical interactions of both inhibitory and stimulatory nature between plants and microorganisms. Bio-dynamic farming differs from other sustainable agriculture methods by the use of the bio-dynamic preparations: mineral, plant or animal extracts, usually fermented and applied after dilution stirring procedures called dynamizations.
Two randomised complete block experiments were carried out with axenic culture of wheat seedlings using Murashige & Skoog salts (1.15 g l-1): experiment 1-with factorial structure to test three different dilutions (10-3, 10-11 & 10-25) of three bio-dynamic preparations (P 500, P505 & P507) three humic acids (HA lab, HA comp and HA 500) and a positive control using IAA (indole-3yl-acetic acid); experiment 2- the same treatments only at the lowest dilution without rhythmic stirring. Both BD preparations, HAs and IAA significantly increased dry weight and shoot length (P=0.042) for the overall interaction between treatments and dilutions ranging from 10*3 to 10*25 in experiment 1. Orthogonal contrasts of interest, also showed similar significant increases. The bio-dynamic preparations were more effective at their approximate field dilutions, HAs at lower dilutions of 10*3, probably through adsorption of nutrients and lowering surface tension in solutions. Activity at dilutions as high as 10*25 is yet unexplained by conventional theories, although modifications in the molecular structure of the diluting medium have been suggested.

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