Mycotoxins are secondary metabolites produced by fungal species that have harmful effects on mammals. The aim of this study was to assess the content of mycotoxins in fresh-cut material of selected forage grass species both during and at the end of the growing season. We further assessed mycotoxin content in subsequently produced first-cutting silages with respect to the species used in this study: Lolium perenne (cv. Kentaur), Festulolium pabulare (cv. Felina), Festulolium braunii (cv. Perseus), and mixtures of these species with Festuca rubra (cv. Gondolin) or Poa pratensis (Slezanka). The mycotoxins deoxynivalenol, zearalenone and T-2 toxin were mainly detected in the fresh-cut grass material, while fumonisin and aflatoxin contents were below the detection limits. July and October were the most risky periods for mycotoxins to occur. During the cold temperatures in November and December, the occurrence of mycotoxins in fresh-cut material declined. Although June was a period with low incidence of mycotoxins in green silage, contents of deoxynivalenol and zearalenone in silages from the first cutting exceeded by several times those determined in their biomass collected directly from the field. Moreover, we observed that use of preservatives or inoculants did not prevent mycotoxin production.

The aim of this study was to investigate the effect of molds on levels of low molecular mass thiols in grasses. For this purpose, the three grass species Lolium perenne, Festulolium pabulare and Festulolium braunii were cultivated and sampled during four months, from June to September. The same species were also grown under controlled conditions. High-performance liquid chromatography with electrochemical detection was used for quantification of cysteine, reduced (GSH) and oxidized (GSSG) glutathione, and phytochelatins (PC2, PC3, PC4 and PC5). Data were statistically processed and analyzed. Thiols were present in all examined grass species. The effect of fungicide treatments applied under field conditions on the content of the evaluated thiols was shown to be insignificant. Species influenced (p < 0.05) PC3 and GSSG content. F. pabulare, an intergeneric hybrid of drought- and fungi-resistant Festuca arundinacea, was comparable in PC3 content with L. perenne and F. braunii under field conditions. Under controlled conditions, however, F. pabulare had higher (p < 0.05) PC3 content than did L. perenne and F. braunii. Under field conditions, differences between the evaluated species were recorded only in GSSG content, but only sampling in June was significant. F. pabulare had higher (p < 0.05) GSSG content in June than did L. perenne and F. braunii.

Meadows occupy more than 23 % of agricultural land in the Czech Republic and also represent the largest pool of carbon in soil organic matter. The organic material is an essential component of healthy soil. Decomposition of organic matter is a biological process, affected by high amount of N and P fertilizer applied in the second half of the twentieth century. This work presents the analysis of the effect of available nutrients nitrogen and phosphorus on the activity of cellulolytic microorganisms in permanent grassland of Sanguisorba-Festucetum comutatae association in the soil surface in the Protected Landscape Area of Žďárské Hills. Contents of available nutrients established by the Mehlich III method were measured ex situ. Data referring cellulose decomposition rates were obtained in situ using the standard mesh-bag method. In the field experiment, the highest loss of cellulose was recorded in variants with the addition of nutrients (PK, 90N + PK and 180N + PK) with result 90.38 % on average. The difference was statistically significant, compared with the control variant without added nutrients 27.87 % (P < 0.05). The added amount of nitrogen in the variant 90 kg of N + PK per ha had no significant effect on loss of cellulose compared to PK variant, as well as variant 180 kg of N + PK per ha. From the results obtained, it is evident that the highest decomposition of cellulose was observed at variant with added phosphorus, compared to variant with nitrogen. Moreover, the effect of different intensity of grassland utilization was found: the amount of decomposed cellulose was higher in two variants (control and 90N + PK) of two cut system in comparison with the same variant in three cut system.

NAWRATH ADAM, ELBL JAKUB, KINTL ANTONÍN, ZÁHORA JAROSLAV, SKLÁDANKA JIŘÍ: The effi ciency of nutrient utilization by permanent grassland in the Kameničky locality. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 6, pp. 1799-1806 This work presents the analysis of the eff ect of grassland management on leaching of mineral nitrogen from rhizosphere and plant biomass production in area of our interest. The determined values show the infl uence of fertilization and species composition of permanent grassland on leaching of mineral nitrogen and biomass production. The values were determined during fi eld and laboratory experiments. The highest availability of N min in the fi eld experiment was detected in the variant N90+PK; the lowest availability of N min was recorded in the PK variant. The diff erence was statistically signifi cant (P < 0.05). In the pot experiment, the highest loss of N min was recorded in the variant with N180+PK (16.88 mg.dm −3