Soil carbon dioxide emission flux from organic and conventional farming in a long term experiment in Tuscany

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). CO
²
emissions proves that soil microbial community in organic farming is more active than conventional (1932.7 and 462.9 kg CO
²
ha
^-1
, respectively). This is also confirmed by the analysis of qCO
²
where organic farming showed approximately three times higher qCO
²
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.