Formation of the Abundance of Microfungi on the Barley Grain Grown as Pure and Mixed Crops in Central and North Estonia

For centuries barley has been an important food crop for mankind. It is important to produce crops that are of good quality and safe to human and animal organisms. However, pathogenic fungi in cereals cause health problems both to humans and animals. In Estonia the microbiological quality of cereals has been studied to identify ”Fusarium” species in feed cereals. Still, the relationship between the agro-ecological conditions and the total abundance of moulds and yeasts on grain has been studied little in Estonia. In 2009 and 2010, we carried out field trials in the experimental station of the Estonian Research Institute of Agriculture in North Estonia (59°18'N, 24°39'E) and in the experimental station of Olustvere School of Service and Rural Economics in Central Estonia (58°33'N, 25°34'E). The variants of the experiment were barley in pure crops with added ammonium nitrate 120 kgN ha^(-1), barley in pure crops with added ammonium nitrate 60 kgN ha^(-1), barley in pure crops with no added ammonium nitrate, and barley.pea mixed crop. After harvesting, the grain was dried to 14% of moisture and grain samples were taken from each trial variant. The abundance of moulds, yeasts, and ”Fusarium” spp. was determined in grain samples using the dilution method. The impact of the levels of nitrogen, location of the trial site, and year (weather conditions) on the abundance of moulds, yeasts, and ”Fusarium” spp. was studied. The common genera of moulds identified were ”Cladosporium, Acremonium”, and ”Fusarium”. According to our results, yeasts were the most common fungi on barley grains. In North Estonia the abundance of moulds was lower compared to Central Estonia. The abundance of fungi was not affected by different levels of nitrogen or whether barley had been grown as a pure crop or a barley.pea mix. The weather conditions had the greatest impact on the abundance of microfungi.