Nutritive value and the content of macroelements in fodder and in soil from organic grasslands

Studies were carried out in the years 2006–2007 in organic farms with animal production and over 30% share of permanent grasslands in agricultural lands. Samples of green forage from meadows and pastures, of hay and hay ensilage from meadow sward were analysed for the content of total protein, crude fibre, crude fat, ash and mineral components (N, P, K, Ca, Mg and Na). In the year 2007, soil (0–20 cm layer) richness in these components was also analysed. Mean content of nutritive components in fodder reached the optimum range but the content of total protein and crude fibre was quite variable. Mean content of potassium and magnesium in all types of fodder was satisfactory, that of phosphorus – satisfactory in green fodder from pastures and slightly deficient in other types of fodder. The content of calcium was minimally deficient in hay and that of sodium was small in all types of fodder (only 0.38 g kg DM in hay), which resulted in too high K:Na ratio (up to 242 in hay) and K:Mg ratio (ca. 10). Compared with conventional farms, more hay samples from organic farms contained more P, Ca and Mg. Potassium content in hay was comparable and Na content was much smaller in hay from organic farms. Soils of studied grasslands were in general acid or slightly acid of low phosphorus content. Very high potassium content in some soils may indicate too often applied liquid manure. Soil richness in available calcium and magnesium was exceptionally favourable and only in few cases needed supplementation. Improving management methods and periodical analyses of soil and fodder are necessary to increase grassland utilization and fodder quality.