Nutritive value of grassland plants: Contents of calcium, phosphorus, magnesium and potassium

The content of calcium (Ca), phosphorus (P), magnesium (Mg) and potassium (K) was analysed in 10 important species of grassland plants. The analyses of more than 500 samples give a better knowledge the influence of species, age and stage of development. The Ca content is clearly higher in the groups of legumes (15,1 ± 2,5 g/kg DM) and herbs (13,7 ± 4,0 g) than in the group of grasses (3,7 ± 1,1 g). The age and the stage of development have little effect. On average, the P concentration in grasses and legumes is similar (3,6 ± 0,8 g/kg DM and 3,4 ± 0,6 g), but it is higher in herbs (4,9 ± 0,9 g). The effect of age and stage of development is important, especially for grasses. The mean concentration of Mg is the highest in herbs (3,2 ± 1,0 g), followed by legumes (2,3 ± 0,5 g) and grasses (1,7 ± 0,5 g/kg DM). The growing cycle has an effect on the Mg content, whereas the age and the stage of development have only  little influence. On average, the K content is almost the same for grasses and legumes (31,8 ± 6,4 g/kg DM and 31,1 ± 5,2 g), but higher for herbs (45,8 ± 6,8 g). It is mostly determined by the growing cycle, the age and the stage of development.