Comparability of the Biodynamic Production System Regarding Agronomic, Environmental and Quality Parameters
Matjaz Turinek
Abstract Biodynamic (BD) agriculture became the subject of research efforts during the last decades, whereas a part of the scientific community looks at the BD method with skepticism and marks it as dogmatic. Summarized data of published research studies showed that further research is needed in the field of food quality comparison/determination, food safety and the environmental performance (e.g. foot prints). In this sense, yields, agronomic efficiency (AE) in relation to yields in some crops and the earthworm populations depending on those crops remain to be explored under the BD production system (PS). Therefore wheat, cabbage and oil pumpkins (rotation 1) and spelt, red beet and false flax (rotation 2) were produced in three successive years (2008-2010) under 4 PS (conventional (CON), integrated (INT), organic (ORG) and BD) + control plots in a field trial near Maribor, Slovenia. Earthworms were determined in rotation 1 in October 2009 and 2010 using the „hot“mustard-extraction method. Yields in the BD PS amounted to 99, 113 and 124 percent of the average yields of all PS for wheat, cabbage and oil pumpkin seeds, respectively. Also AE of N, Nmin, P and K of the BD system for the production of all crops studied in rotation 1 was in the upper half of all PS under investigation. Moreover, earthworm populations and biomass were highest and on a similar level in the BD and ORG systems in all three crops investigated, where most were found in oil pumpkins. In the second step the ecological footprint of PS under study was calculated for wheat and spelt production and interpreted using the SPIonExcel tool. Three-year results show a markedly lower ecological footprint of the ORG and BD systems in production of both crops, mainly due to non-use of external production factors. When yields are added to the equation, the ORG and BD systems also have a lower overall footprint per product unit and ecological efficiency of production. Thus, ORG and BD systems present viable alternatives in facing environmental degradation and climate change in cereal production. However, room for improvement exists in the area of machinery use in all systems studied and yield improvement in the ORG farming system. Moreover, the importance of food quality has increased, but there remains a lack of research in this field, including sensory quality. Thus, in the third step, yields and sensory properties of white cabbage and red beet were examined in 2008 and 2009. Yields did not differ significantly among PS. A total of 167 consumers scored four attributes (color, odor, taste, and willingness to buy) using a nine-point hedonic scale. Results show significant differences between PS for both crops, where INT and control cabbage was preferred over CON cabbage samples (BD and ORG in-between), whereas BD and control red beet was preferred over CON and INT samples (ORG in-between). Lastly, the contents of sugars, organic acids, total phenolic content and the antioxidant activity were quantified in the flesh of red beet samples from 2009 using established methods. Significant differences were measured for malic acid, total phenolic content (TPC) and total antioxidant activity, where malic acid content ranged from 2.39 g kg-1 FW (control) to 1.63 g kg-1 FW (CON, ORG and INT). Highest TPC was measured in BD and control samples (0.677 and 0.672 mg GAE g-1, respectively), lowest in CON samples (0.511 mg GAE g-1). Antioxidant activity was positively correlated with TPC (r2=0.6187) and ranged from 0.823 µM TE g-1 FW to 1.270 µM TE g-1 FW in CON and BD samples, respectively, whereas total sugar content ranged from 21.03 g kg-1 FW (CON) to 31.58 g kg-1 FW (BD). The importance of the measured constituents for human health, as well as for plant resilience and health is discussed and put into perspective. Thus, the BD PS presents a viable alternative to the nowadays predominant CON and INT PS for the production of the studied crops under the Slovene subcontinental temperate climate.
Keywords: biodynamic farming, agronomic efficiency, earthworms, ecological footprint, sensory quality, chemical composition