Organic and Biodynamic Management: Effects on Soil Biology

marily in the use of fermented preparations in compost and as field sprays. These unique preparations (Table Biodynamic agriculture is a unique organic farming system that 1) consist of specific minerals or plants treated or ferutilizes, in addition to the common tools of organic agriculture, specific fermented herbal preparations as compost additives and field sprays. mented with animal organs, water, and/or soil (Steiner, The objective of this work was to determine whether biodynamic 1974). The preparations were developed to improve soil compost or field spray preparations affect the soil biological commuand crop quality and hasten composting (Koepf et al., nity in the short term, beyond the effects of organic management. Four 1976). Six preparations (numbered 502–507) were apfertilizer options: (i) composted dairy manure and bedding (organic plied to compost piles and three more preparations (500, fertilization), (ii) the same material composted with biodynamic com501, and 508) were applied directly to soil or crops post preparations, (iii) mineral fertilizers, and (iv) no fertilizer were as field sprays. Their primary purpose was not to add investigated with and without the biodynamic field spray preparations. nutrients, but to stimulate the processes of nutrient and Both biodynamic and nonbiodynamic composts increased soil microenergy cycling (Koepf et al., 1976). If the preparations bial biomass, respiration, dehydrogenase activity, soil C mineralized affect nutrient cycling, they may have their effect via in 10 d (MinC), earthworm (Lumbricus terrestris ) population and biomass, and metabolic quotient of respiration per unit biomass soil microorganisms that mediate many nutrient trans(qCO2) by the second year of study. No significant differences were formations. The aim of this work was to test biodynamifound between soils fertilized with biodynamic vs. nonbiodynamic cally prepared compost and the field spray preparations compost. Use of biodynamic field sprays was associated with more for effects on soil biotic parameters and to compare the MinC and minor differences in soil microbial fatty acid profiles in effects of biodynamic soil management with the effects the first year of study. There were no other observed effects of the of organic fertilization with dairy compost. biodynamic preparations. Organically and biodynamically managed Soil quality is often described as the soil’s natural soils had similar microbial status and were more biotically active than ability to produce good yields of high-quality crops and soils that did not receive organic fertilization. Organic management protect human and animal health without harming the enhanced soil biological activity, but additional use of the biodynamic natural resource base (Parr et al., 1992; Doran and Parpreparations did not significantly affect the soil biotic parameters tested. kin, 1994). The meaning and quantification of soil quality depend on chemical, physical, and biological parameters. Of these, the biological measurements are least understood (Kennedy and Papendick, 1995). Because O agriculture disallows the use of synthetic of its claimed reliance on beneficial microbial activity pesticides and fertilizers, relying instead on culand enhanced soil quality, biodynamic agriculture is a tural, biological, or natural methods of pest control and potential case study of biological soil quality. fertility. A growing number of studies show that organic Generally studies have found that biodynamically farming leads to higher quality soil and more soil biologfarmed soils have better soil quality than conventionally ical activity than conventional farming. Drinkwater et farmed soils (Reganold, 1995). Fertilization with biodyal. (1995) documented higher pH, organic C and N, N namic compost can result in more organic C and N, mineralization potential, and actinomycete abundance dehydrogenase activity, biomass, and a higher dehydroand diversity in organic fields as compared with convengenase/biomass ratio than fertilization with chemical tionally managed fields. Reganold (1988) found greater fertilizer or nonbiodynamic compost (Abele, 1976). pH, organic C and N, cation-exchange capacity, microGoldstein (1986) found that biodynamically managed bial biomass, and several microbial enzymes in organic plots had more organic matter, microbial biomass, and than in conventionally managed soils. Other studies respiration than conventional or organic systems. In the have found similar benefits of organic soil management DOC (bio-Dynamic, Organic, Conventional) plots (Fraser et al., 1988; Wander et al., 1994; Workneh and maintained in Therwil, Switzerland, since 1978, biodyvan Bruggen, 1994; Gunapala and Scow, 1998). namically managed plots had greater microbial biomass Biodynamic farming is a type of organic farming and even than the organic plots, while biodynamic and orhas many similarities to other organic farming systems, ganic plots both had greater microbial activity (basal including a reliance on organic fertilizers. Biodynamic respiration and dehydrogenase activity) than convenagriculture differs from traditional organic systems pritional, mineral-fertilized, or unfertilized plots (Mäder et al., 1995). In an ongoing study, Penfold et al. (1995) L. Carpenter-Boggs and J.P. Reganold, Dep. Crop and Soil Sciences, found that biodynamic management resulted in lower 201 Johnson Hall, Washington State Univ., Pullman, WA 99164-6420; A.C. Kennedy, USDA-ARS, Land Management and Water Conservaextractable P than conventional or organic management tion Research Unit, 215 Johnson Hall, Washington State Univ., P.O. Box 64621, Pullman, WA 99164-6421. L. Carpenter-Boggs currently Abbreviations: FAME, fatty acid methyl ester; HSD, Tukey’s honestly at USDA-ARS, North Central Soil Conservation Research Lab., 803 significant difference; PC, principal component; PCA, principal comIowa Ave., Morris, MN 56267. Received 12 Aug. 1999. *Correspondponent analysis; MinC, mineralized C; qCO2, metabolic quotient of ing author ([email protected]). respiration per unit biomass; SIR, substrate induced respiration; TBME, tert-butyl methyl ether. Published in Soil Sci. Soc. Am. J. 64:1651–1659 (2000).