The effect of soil conditioners on the content of soluble carbohydrates, digestible protein and the carbohydrate–protein ratio in Lolium perenne and Dactylis glomerata

A three-year field experiment (52.169°N, 22.280°E), in which each treatment was replicated three times, was set up in a randomised split-plot design in the autumn of 2011. The main experimental factors were soil conditioners with the trade names such as UGmax, Eko-Użyźniacz and Humus Active Papka, which were applied on their own and with mineral fertilisers. They were applied to the soil with two forage grasses: the Bora variety of Dactylis glomerata and Lolium perenne of the Info variety. The results were processed statistically with the multi-factor analysis of variance with a significance level of P≤0.05, whereas the differences between means were verified with Tukey’s test. The Statistica 12 program was used to do all the calculations. Compared to the control, soil conditioners (UGmax, Humus Active and Eko-Użyźniacz) did not reduce carbohydrate content in grass significantly. This proves that they can be applied to grass. Combination of mineral fertilisers with soil conditioners, relative to the control, resulted in about 15% increase in digestible protein content. Comparing all the plots, without the control, the ratio of non-structural carbohydrates to protein was the most favourable in the grass from plots where UGmax or nitrogen-phosphorus-potassium (NPK) fertiliser or a combination of both was applied.