Effect of Different Factors on Chemical Composition of Grass-legumes Sward

The biological value of fodder is estimated on the basis of its content of particular macroelements (N, P, K, Ca, Mg). Concentration of these components in fodder depends on many factors, mainly on the properties of soil, type of land use and growth phase of crops. The aim of this paper was to estimate the effect of soil properties, land use and species composition of a sward mixture on the content of macroelements, total protein and acid detergent fibre in grass-legumes sward. In 2002-2005 a field study was carried out on mineral and organic soil in Sosnowica (near the Wieprz-Krzna Canal). Two land use types were tested: pasture (sward grazed by cattle) and simulated (sward frequently cut, proportionally to the grazings). Six grass-legumes mixtures were sown, including the following species: Poa pratensis, Festulolium braunii, Festulolium loliaceum (2 strains), Lolium perenne and Festuca pratensis. Tetraploid hybrids of Festulolium loliaceum [Festuca pratensis (4x) x Lolium perenne (4x) were obtained at the Institute of Plant Genetics PAS in Poznañ. Pasture sward was grazed by Limousine cattle 5-6 times during the grazing season, while the simulated sward was cut at the same time. Chemical composition of fodder (total protein, ADF, P, K, Ca, Mg) was estimated. Sward on organic soil was characterized by a significantly higher content of total protein, phosphorus, calcium and magnesium as well as a significantly lower content of potassium in comparison to sward on mineral soil. Moreover, a significantly higher content of potassium and significantly lower content of magnesium in pasture sward were observed. Sward was of perfect quality (content of ADF) and had an optimum content of basic macroelements. No influence of the examined species in the mixtures on feed quality was observed. Consequently, compared to the other species, Festulolium loliaceum hybrids prove to be suitable for to pasture mixtures in a postboggy habitat. .