Pesticide use in organic agriculture is much smaller than in conventional farming. Annex II of Regulation 889/2008 (European Commission, 2008) lists these biopesticides. Most of them are used as insecticides and fungicides, all derive from natural sources and include naturally occurring chemicals, pheromones, bacteria, fungi and insect predators. University of Hertfordshire (2016) points out that these substances may cause environmental risks, too: the BioPesticide DataBase (BPDB) is a comprehensive relational database of data relating to pesticides derived from natural substances.

However, Pelosi et al. (2013) compared field data from conventional versus organic cropping systems with regards to pesticide pressure on three different species of earthworm populations living on the soil surface layer. All fields were plowed conventionally, were cultivated with the same crop (winter wheat) at the sampling times and received either mineral or organic fertilisation. The authors detected decreasing earthworm densities with increasing (conventional) pesticide applications according to the Treatment Frequency Index (TFI), with insecticides having the most negative impact on earthworm populations, followed by herbicides and fungicides.

Lysimeter trials in Hesse and Saxony between 1996 and 2011 revealed that organic farming may bear a risk of nitrogen leaching due to generally intensive legumous nitrogen fixation and organic fertiliser-use as well as plant residues on the field. However, under the premisis of a groundwater-preserving cultivation, the potential for nitrate leaching in organic farming is approximately 10 kg N/ha lower that in conventional farming (40 %). This is due to lower autumn Nmin-values, to a wider crop rotation and a larger proportion of grassland in organic versus conventional farms (Fink et al., 2013 and 2014). A study in Paris basin indicated, that the amount of excess nitrogen potentially leaching ranges from 14 to 50 kg N/ha below organic farming plots and from 32 to 77 kg N/ha below conventional farming plots (Benoit et al., 2013).

National, regional and local data bases may serve as sorce of information on the degree of distribution of organic farming. For the reference year 2013, number and size of farms fully converted and under conversion to organic farming are listed by the Eurostat database [ef_lus_main]. Land in organic faming can be used as an indicator for the pressure of pesticides and nitrates.


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