Occurrence of moulds and mycotoxins in grass-legume silages influenced by nitrogen fertilization and phenological phase at harvest

Abstract

The aim of this study was to determine the presence of fungi and concentrations of mycotoxins, zearalenone, fumonisin and deoxynivalenol, in lucerne and grass-legume silages, under the influence of different doses of N fertilization and harvesting at different stages of phenological development of the plants. Studies included pure lucerne crop and mixtures of lucerne with cocksfoot, tall fescue and sainfoin, sown in different ratios, fertilized with 0, 70, 140 or 210 kgN ha(-1) and harvested in the butonization phase or at 50% flowering of lucerne plants. Results showed that the total fungi count in the silage depended on the three investigated factors. The highest total fungi count was determined in the mixture silages of lucerne, cocksfoot and tall fescue, which was well treated with different nitrogen quantities, harvested and prepared in later stages of plant development. The most commonly-occurring fungi were Fusarium species (85.5% of fungi were this genus). Of the studied mycotoxins, only DON depended on fertilization, as it reduced the concentration of DON from 0.15 to 0.07 mg kg(-1). Preventing appearance of fungi and their mycotoxins in forage and silage should begin in the field as well as during the process of preparation of silage.