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1. Yields of several years

Effects of preparations on yields were usually examined on the same sites during several
years in a row. Repeatedly, the following characteristics were noticed:

• the preparations did not cause the same effects in each year.
• the biggest differences were mostly found in years with generally low yield levels.
• the application frequency of the preparations evidently had no significant influence on the  effect.

Wheat: At low yield levels in 1973, plots treated with preparations achieved 17 % or 21 % higher yields. In the three following years, at higher yield levels, biodynamic preprations could generally not increase yields. The threefold application of horn silica normally showed the same effect as the sixfold application.










Carrots: There was also only an difference in yield in the year with the lowest yield level (1973). Carrot yields increased of 13% and 26% respectively when preparations were applied.










Beetroot: Yield levels were quite similar in both years. However, the treatments with preparations showed significant increases only in one year.  The frequency of application of horn manure did not show any effect.

Obviously, the effects of preparations are not only depending on yield levels of a certain year.




Reference:
SPIESS, H. (1978): Konventionelle und biologisch-dynamische Verfahren zur Steigerung der Bodenfruchtbarkeit. Diss. Uni Gießen 

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Slurry treated with biodynamic preparations, delivered a higher dry matter yield of grass-clover. By trend, it furthermore  increased the proportion of clover compared to slurry without preparations (Abele, 1978).

 

Reference:
ABELE, U. (1978): Ertragssteigerung durch Flüssigmistbehandlung. KTBL-Schrift 224, Landw.-Verlag, Münster- Hiltrup.

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2. Means of several years

Regarding the means of eight years, the preparations caused significantly higher yield only for potatoes, but not for rye and wheat.  The treatment  CMBD comprised the application of all compost preparations and spray preparations.

Yields (dt ha^-1) as a function of type and level of fertilization, mean values of the crop rotation periods of 1992-95 and 1996-99 (Raupp, 2001)

	CM	CMBD	MIN	low	medium	high
Winter rye	28.3 a	29.8 a	37.7 b	28.1 a	31.7 b	36.1 c
Spring wheat	38.9	39.3	41.0	36.8 a	40.2 b	42.2 c
Potatoes	247 a	262 b	271 b	230 a	262 b	288 c
Mean values with different letters within a column are significantly different (p<0.05).

For more detailed descriptions of the experiment, see

Reference:
RAUPP, J. (2001): Manure fertilization for soil organic matter maintenance and its effects upon crops and the environment, evaluated in a long-term trial. In: Rees, R.M.; Ball, B.C.; Campbell, C.D.; Watson, C.A. (eds.), Sustainable management of soil organic matter. CAB International, Wallingford UK; 301-308  Download the PDF file

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3. Yield effects in years with different yield levels

Depending on yield levels, the preparations had opposing effects on yields of different crops.

Bivariate correlation between spring wheat yield with composted manure without preparations (CM) and composted manure with preparations (CMBD),  (n = 55; 14 years, 4 replicates per treatment; main axis of the ellipse: p<0.05);  Raupp (1999)

The Figure shows the yields of spring wheat as an example. The yield with composted manure without biodynamic preparations (CM) is plotted against the horizontal axis and the yield achieved in the same year with composted manure including the application of all biodynamic preparations (CMBD), is plotted against the vertical axis.
Under low yielding conditions, the preparations increased yields (CMBD > CM); whereas at high yield levels the yields were reduced by the preparations (CMBD < CM). The slope of the major axis of the correlation ellipse is significantly smaller than 1 (p<0.05), providing evidence of the described effect.

The same phenomenon was found for variants with application of horn manure and horn silica (calculated by Raupp & König, 1996). The data originated from 28 different pot and field trials, which were realized on the same site with wheat, carrots, beetroot and potatoes by Spieß (1978) and Kotschi (1980).



References:
KOTSCHI, J. (1980): Untersuchung zur Wirkung der in der Biologisch-Dynamischen Wirtschaftsweise verwendeten Spritzpräparate "500" und "501" auf landwirtschaftliche Kulturpflanzen. Diss. Uni Gießen

RAUPP, J. (1999): Biodynamic approaches in research and development. In: Zanoli, R.; Krell, R. (eds.); Research Methodologies in Organic Farming. FAO Regional Office for Europe, REU Technical Series 58; 41-47 Download the PDF file

SPIESS, H. (1978): Konventionelle und biologisch-dynamische Verfahren zur Steigerung der Bodenfruchtbarkeit. Diss. Uni Gießen

Further references to this phenomenon:
KÖNIG, U.J. (1993): Systemregulierung - Ein Wirkungsprinzip der biologisch-dynamischen Präparate. In: Zerger, U. (Hrsg.); SÖL-Sonderausgabe Nr. 42, 394-396

RAUPP, J.; KÖNIG, U.J. (1996): Biodynamic preparations cause opposite yield effects depending upon yield levels. Biol. Agric. & Hort. 13, 175-188