Yield and Quality of Straw of Italian and Perennial Ryegrass Cultivated for Seed Production

Abstract

Italian, annual and perennial ryegrasses are the most important grass species cultivated for seed production in the Czech Republic. The straw remaining after seeds threshing can be used as low quality forage, bedding material or as soil amendment. However, there are no comprehensive information concerning grass straw yields and quality in central Europe. The aim of this study was to investigate the Italian (IR) and perennial (PR) ryegrass straw yield and quality. These parameters were measured for two harvest years at two locations. IR did not provide statistically higher straw yield than PR (7.50 and 7.17 t.ha–1 respectively, p = 0.314), but dry matter (DM) content immediatelly after threshing was higher than for PR (0.42 and 0.38 respectively, p = 0.03). IR straw had the same content of ash and hemicellulose (mean 69.8 and 216 g.kg–1 DM, p = 0.22 and 0.57), but less crude protein (64.1 and 81.4 g.kg–1 DM, p = 0.003), more fibre (399 and 382 g.kg–1 DM, p = 0.02), NDF (656 and 629 g.kg–1 DM, p = 0.03) and ADF (442 and 412 g. kg–1 DM, p = 0.000) when compared with PR straw. Most of the parameters were affected by the year (with exception of crude protein) and by location (with exception of yield, DM content, ash and crude protein). There were no differences in mineral nutrient contents between species. The highest values were found in potassium (19.8 g.kg–1 DM) what is comparable with average quality hay. Phosphorus, calcium and magnesium contents (1.42, 2.96 and 1.02 g.kg–1 DM) were substantially lower than in hay. Data concerning ryegrasses straw yield and quality from the USA are comparable with our results and can be used for European conditions.