Výnosy vytrvalých trav v létě a na konci vegetačního období

Abstract

The paper deals with the yields of Festulolium, Dactylis glomerata, Arrhenatherum elatius and Festulolium-Dactylis glomerata mixture during the growing season and at the end of the growing season. The yields were assessed in the Bohemian-Moravian upland at 560 m a.s.l. A small-plot experiment was established in three repetitions. The assessment was made in three subsequent years. The experiment was annually fertilized with 50 kg . ha−1 N, 30 kg . ha−1 P and 60 kg . ha−1 K. Evaluated were dry matter yields and RYT values (Relative Yield Total) in the mixture of Festulolium and Dactylis glomerata. In summer, the sward was used either for one cut (harvest in early June) or two cuts (harvests in early June and late July). At the end of the growing season, the stand was harvested in October or in November or in December. Yields of the first cut in early June ranged from 5.90 to 9.12 t . ha−1. Yields of the second cut in late July ranged from 1.05 to 4.60 t . ha−1. Statistic difference between the species was significant (P < 0.05) in the respective cuts. Total yields of dry matter in the growing season ranged from 7.51 to 10.05 t . ha−1. Number of cuts and year showed a statistically highly significant influence (P < 0.01) on DM yields. The mixture of Festulolium and Dactylis glomerata exhibited an additive relation (RYT = 1) in the first cut and an antagonistic relation (RYT < 1) in the second cut. At the end of the growing season, the yields ranged from 0.71 to 2.27 t . ha−1. Average yields of one-cut swards (harvested in summer in early June) were at the end of the growing season 2.27 t . ha−1 and average yields of two-cut swards (harvested in summer in early June and late July) were 0.79 t . ha−1. From October to December, the yields were decreasing from 1.78 to 1.32 t . ha−1. Species, number of cuts in summer, harvest date at the end of the growing season and year showed a statistically highly significant influence (P < 0.01) on dry matter yields. In the first two production years, the mixture of Festulolium and Dactylis glomerata exhi­bi­ted an antagonistic relation (RYT < 1) at the end of the growing season. In the third production year, the relation between Festulolium and Dactylis glomerata as expressed by the RYT value could be identified as synergic (RYT > 1).