Short-Term Effects of Biogas Digestates and Pig Slurry Application on Soil Microbial Activity

Table 6

Effect concentrations lowering potential ammonia oxidation rate (PAO) and potential denitrification activity (PDA) in the soil by 10, 50, and 90% (EC₁₀, EC₅₀, and EC₉₀) in response to addition of four types of biogas digestates (BD-A, BD-B, BD-C, and BD-D) and pig slurry (PS).

Test	Effect parameter	Residue type
		BD-A	BD-B	BD-C	BD-D	PS
PAO	EC10 (kg -N ha^−1)	136	30	98	271	20
	EC50 (kg -N ha^−1)	140	45	156	291	50
	EC90 (kg -N ha^−1)	144	68	250	312	128
	^2 of nonlinear regression	0.99	0.98	0.99	0.93	1.00
PDA	EC10 (kg -N ha^−1)	141	120	87	55	n/a
	EC50 (kg -N ha^−1)	318	287	346	238	n/a
	EC90 (kg -N ha^−1)	714	685	1381	1029	n/a
	^2 of nonlinear regression	0.98	0.98	0.97	0.98	n/a

n/a = values not obtainable (no inhibitory effect).