Organic and biodynamic management: Effects on soil biology

Biodynamic agriculture is a unique organic farming system that utilizes, in addition to the common tools of organic agriculture, specific fermented he rbal preparations as compost additives and field sprays. The objective of t his work was to determine whether biodynamic compost or field spray prepara tions affect the soil biological community in the short term, beyond the ef fects of organic management. Four fertilizer options: (i) composted dairy m anure and bedding (organic fertilization), (ii) the same material composted with biodynamic compost preparations, (iii) mineral fertilizers, and (iv) no fertilizer were investigated with and without the biodynamic field spray preparations. Both biodynamic and nonbiodynamic composts increased soil mi crobial biomass, respiration, dehydrogenase activity, soil C mineralized in 10 d (MinC), earthworm (Lumbricus terrestris) population and biomass, and metabolic quotient of respiration per unit biomass (qCO(2)) by the second y ear of study. No significant differences were found between soils fertilize d with biodynamic vs. nonbiodynamic compost. Use of biodynamic field sprays was associated with more MinC and minor differences in soil microbial fatt y acid profiles in the first gear of study. There were no other observed ef fects of the biodynamic preparations. Organically and biodynamically manage d soils had similar microbial status and were more biotically active than s oils that did not receive organic fertilization. Organic management enhance d soil biological activity, but additional use of the biodynamic preparatio ns did not significantly affect the soil biotic parameters tested.