Title pageSoil microbiome biomass, activity, composition and CO2 emissions in a long term organic and conventional farming systems.

Biodynamic agriculture (BD agriculture) was presented as an alternative form of agriculture by the philosopher Rudolf Steiner and is nowadays considered one of the forms of organic agriculture. The objective of the present manuscript is to critically review international scientific literature on biodynamic agriculture as published in highly ranked journals and to assess its performance. This review was based on a structured literature survey of peer-reviewed journals indexed on the Web of Science™ (WoS) Core Collection database carried out from 1985 until 2018. We found 147 publications of studies in journals with an impact factor. Of these, 93 focused on biodynamic agricultural practices, 26 on the sustainability of the biodynamic method, and 28 on the food quality of biodynamic products. The results of the literature review showed that the BD method enhances soil quality and biodiversity. Instead, further efforts are needed to implement knowledge on the socio-economic sustainability and food quality aspects of BD products. One particularly promising topic of research consists in the assessment of microbial activity and the potential that microbiomes have in BD farms to enhance soil fertility and human health following the One Health approach. Moreover, it is critical that such subjects be investigated using a systemic approach. We conclude that BD agriculture could provide benefits for the environment and that further efforts should be made with research and innovation activities to provide additional information to farmers, policy makers, and stakeholders regarding this type of organic agriculture.

Soil microbial biomass represents a significant factor for the evaluation of soil fertility. In the present study we evaluated the development of the soil microbial biomass and soil CO2 emissions in two different agricultural systems: organic and conventional farming on sunflower. Organic farming ensures a higher development of soil microbial community than conventional farming (average 29.1 and 22.5 kg DNA ha -1 , respectively). CO2 emissions proves that soil microbial community in organic farming is more active than conventional (1932.7 and 462.9 kg CO2 ha -1 , respectively). This is also confirmed by the analysis of qCO2 where organic farming showed approximately three times higher qCO2 than conventional farming (66.3 and 20.5, respectively). However, crop yields highlighted as conventional farming is still more productive than organic farming. This is mainly due to the reduced amount of N that a mix of green manure (legumes and cereals) provide to the successive crop.

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