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14.10.2009
International Conference on the issue of seed laws and their impact on landraces, population and conservation
02.10.2009
Vital soil Vital food - Biodynamic Soil Conference

Effects of farmyard manure compost and biodynamic preparations

Long-term trial at IBDF Darmstadt (since 1980)

since 1992 Agroecology; crop climatology

Third period (research focus: Yield formation and long-term effects)

Research problem:
A lower crop density is developed with organic fertilization, and light incidence onto the soil surface is more intensive. Is the consequence of this that the soil is warmer and N mineralization is stimulated? (Explanation)

**Crop density (originating from 285 viable seeds m^-2) and rel. incidence of light (%) in the rye stand at various distances from soil surface, for organic and mineral fertilization (Raupp, 1999)**
		Composted manure	Mineral fertilizer
Plants m^-2 Ears m^-2		197 312 a	205 361 b
Light (%)	at 70 cm at 30 cm at 5 cm	52.8 a 26.7 a 15.3 a	42.5 b 17.5 b 9.0 b
Values in a row with different letters are significantly different (p<0.05).

Shadowing effect was weaker in the organically fertilized rye stand.
With both types of fertilizer the same number of plants established themselves. Finally, however, mineral fertilization led to a considerably higher number of ears.

As was to be expected, light incidence at each height was reduced more by the dense crop.

**Soil temperature (°C) on sunny and cloudy days at various soil depths between rye rows as a function of application of composted manure (CM) and mineral fertilizer (MIN); Raupp (1999)**
		Sunny days			Cloudy days
		in the morning	at noon	in the evening	in the morning	at noon	in the evening
5 cm	CM MIN	16.3 16.1	25.2 b 24.3 a	22.3 b 21.8 a	13.8 13.6	14.7 14.4	15.0 14.7
10 cm	CM MIN	17.6 17.1	24.2 b 22.7 a	22.6 b 21.7 a	14.8 14.6	14.3 14.3	14.1 14.0
15 cm	CM MIN	17.2 16.9	22.4 b 21.8 a	22.1 b 21.3 a	15.0 14.8	14.8 14.6	14.5 14.3
The fertilization effect for one soil depth, time and weather type is significant, if values are marked with different letters (p<0.05).

Temperature variation over day was only detectable on sunny days.

As a result of lower shadowing the soil became warmer in manure-fertilized plots. The difference was measurable even at 15 cm soil depth and lasted until the evening.

On cloudy days soil temperature showed neither a variation over the day nor differences owing to fertilization.

The temporarily warmer soil had no effect on N mineralization.
The net N mineralization of a standard soil (buried in the plots at 5 cm depth in PE bags) was not significantly different in minerally and manure fertilized plots (13.6 and 16.5 ppm nitrate N g^-1 DM, resp., after 6 weeks of incubation). Evidently the observed temperature deviation was not large enough to cause such an effect.

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