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Effects of farmyard manure compost and biodynamic preparations

Long-term trial at IBDF Darmstadt (since 1980)

1988-1991 Soil organic matter and biological activity

Second period (research focus: Soil biology)

Reference (except where otherwise stated): BACHINGER (1996)

**C_org contents in topsoil after 9 years (1989) of fertilization with manure (CM, CMBD) and mineral fertilizer (MIN) at three intensities**
	CM	CMBD	MIN	average
low medium high	0.86 0.91 0.98	0.97 1.02 1.09	0.81 0.80 0.81	0.88 a 0.91 a 0.96 b
average	0.92 b	1.02 c	0.81 a
Mean values of a factor with different letters are significantly different (p<0.05). BACHINGER (1996).

The highest C_org contents emerged from application of composted manure and biodynamic preparations.
The same amounts of composted manure without the preparations (CM) led to lower C_org contents. The lowest contents were observed with mineral fertilization (MIN). The results increased in step with rising manure amounts but not in step with rising amounts of mineral fertilizer (least sign. difference for the interaction of type by intensity of fertilization: 0.038; p<0.05). Note: Straw was removed in CM and CMBD and left on the plots in MIN.

Several years passed until the new C_org levels were established, depending upon fertilization type.
A rough differentiation into 3 levels already began to emerge 1-2 years after the beginning of the trial. However, the results did not stabilize until 7 years had passed.

The figure shows averages of the 4 fields (cross-line in the bars) and their standard deviation s (length of the bars) at the medium fertilization intensity (Bachinger, 1996).

**Microbiological parameters and ratios in topsoil, by type and intensity of fertilization, 1989 data (Bachinger, 1996)**
	PA¹	C_mic²	DHA³	PA/C_org	C_mic/C_org	DHA/C_org
				relative to MIN = 100
CM	0.27 b	34.9 b	109.1 b	116	106	123
CMBD	0.26 b	37.8 b	121.9 c	97	102	120
MIN	0.20 a	26.1 a	75.9 a	100	100	100
				relative to low = 100
low	0.25 a	30.6 a	94.5 a	100	100	100
medium	0.25 a	34.1 a	103.8 a	94	105	116
high	0.23 a	34.2 a	108.6 a	83	100	111
¹ protease activity (mg Tyr/g) ² microbial biomass (SIR; mg C/100 g) ³ dehydrogenase activity (µg TPF/10 g) Mean values of a factor with different letters are significantly different (p<0.05).

Higher enzyme activities and larger microbial biomass with manure fertilization.
Microbial biomass and activity parameters - both absolute values and their ratios to soil organic carbon - have been found to be higher with manure than with mineral fertilization.

The same effects as in 1989 (see table) have also been observed in other years (and in other fields) during the research period (see next table). In some cases the results have been further increased in the treatment with biodynamic preparations.

A higher dehydrogenase activity in various treatments with the preparations has also been reported from other long-term trials.

Soil biological parameters with manure fertilization with (CMBD) and without (CM) biodynamic preparations and with mineral fertilization (MIN), results in relation to mineral = 100; data of different fields in 1989-91, averages of 3 fertilization intensities (Bachinger, 1996)
	DHA¹	PA²	DRA³	ATP⁴	N_mic⁵	C_mic⁶	C_org⁷	N_t⁸	DHA/C_org
CM	129	125	118	128	115	114	115	113	112
CMBD	144	130	127	144	126	126	131	129	110
MIN	100	100	100	100	100	100	100	100	100
¹ dehydrogenase activity ² protease activity ³ dimethylsulphoxide reductase activity ⁴ adenosine triphosphate content ⁵ microbial biomass nitrogen (chloroform fumigation extraction) ⁶ microbial biomass carbon (substrate induced respiration) ⁷ organic carbon ⁸ total nitrogen

Positive effects of organic fertilization with preparations have been observed in the subsoil, too.
At 25-55 cm depth, the organic carbon content and dehydrogenase activity have been higher in the manure treatment with preparations than in the mineral treatment.

Organic carbon content and dehydrogenase activity by manure fertilization with (CMBD) and without (CM) biodynamic preparations and with mineral fertilization (MIN) in topsoil and subsoil (Bachinger, 1996)
	Fertilization	Topsoil¹	rel. to MIN	Subsoil	rel. to MIN
C_org (%)	CM CMBD MIN	0.99 b ² 1.21 c 0.80 a	124 151 100	0.27 a 0.37 b 0.26 a	104 142 100
DHA ³	CM CMBD MIN	164.0 b 184.5 c 126.8 a	129 146 100	20.8 a 29.1 b 15.3 a	137 191 100
¹ topsoil: 0 - 25 cm, subsoil: 25 - 55 cm ² Values of a soil horizon with different letters are significantly different (p<0.05) ³ dehydrogenase activity (µg TPF 10g ^-1 24 h^-1)

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