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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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