Italian Ryegrass (Lolium multiflorum Lam.) Fiber Fraction Content and Dry Matter Digestibility Following Biostimulant Application against the Background of Varied Nitrogen Regime

An experiment was conducted to determine the effect of an application of biostimulants, against the background of varied nitrogen regime, on the share of neutral detergent fraction (NDF), acid detergent fraction (ADF), and acid detergent lignin (ADL) in the crude fiber fraction of Italian ryegrass as well as its digestibility. A field experiment was arranged as a randomized subblock design (split-plot) with three replicates at the Siedlce Experimental Unit of the University of Natural Sciences and Humanities in Poland in 2013. The following factors were examined: type of biostimulant: Algex, Tytanit, Asahi SL and a control; nitrogen application rate: 0 (control); 120 and 180 kg·ha−1. There were confirmed positive effects resulting from an application of biostimulants in Italian ryegrass cultivation. There was confirmed the assumed hypothesis that an application of both natural and synthetic biostimulants will make it possible to improve the feeding value of grasses by reducing the fiber fraction. Particular attention should be paid to the biostimulant Algex whose application in Italian ryegrass cultivation produced the most beneficial response in terms of the share of NDF, ADF, and ADL fractions, which resulted in the greatest increase in the plant dry matter digestibility. Increasing nitrogen rates significantly reduced the quantity of analyzed fiber fractions, and increased grass digestibility.