DYNAMIKA OBSAHU ENERGIE A ORGANICKÝCH ŽIVIN VE STEPNÍCH POROSTECH NÁRODNÍ PŘÍRODNÍ REZERVACE MOHELENSKÁ HADCOVÁ STEP

Abstract

The aim of the study was to determine the dynamics in the content of organic nutrients, ash and energy in dry matter of growths within the Mohelenská Serpentine Steppe National Nature Reserve (NPR), and to document their initial nutritive value before the intended grazing. Plant samples in 1995 and 1996 during the growing season in 14-days intervals from the area of 3 × 1 m2. Amounts of dry matter, fibre, nitrogen substances, fat and ashes were determined in growths according to the ANONYM (2001). Nitrogen-free extract substances (BNLV) were determined by final calculating; BE, ME, NEL, NEV, PDIN and PDIE were calculated using the regression equations (VESELÝ and ZEMAN, 1995, 1997). Combining ratio (SP) was calculated according to the relation: SP = PDIN (g)/NEL (MJ). The dynamics of the contents of dry matter, organic nutrients, ashes and energy were assessed in the growth during the vegetation period and the dynamics was compared with standardized requirements of sheep (no pregnant ewe). Regression and correlation relations for nutrition value of the growths during vegetation period were calculated by use of mathematical-statistical analysis. Only statistically significantly (P<0.05) different parameters form the zero are presented in the paper. The content of dry matter in the growths culminated in summer months (places D8, E13, B17) and it was accompanied by depression in autumn months. After the highest content of crude protein, PDIN and PDIE recorded in spring months summer depression (August) followed, this depression was partly balanced by autumn growth of vegetation. The content of ash in steppe growths increased during evaluated period. Similar tendency was registered for fat. Also the contents of fibre and BNLV linearly increased. The contents of nitrogen nutrients and energy corresponded with standardized requirements for sheep during whole vegetation period. Conversely the content of fibre highly exceeded the requirement except in spring months. With regards to requirements of sheep the steppe growths contained relative excess of PDI in autumn season and excess of NEL in summer season.