Fiber Fraction Content in Legume–Grass Mixtures Treated with Mushroom Substrate and Cow Slurry

CORE IDEAS: Mushroom substrate application to legume grass mixtures increased neutral detergent fiber content in the forage more than slurry.The mixture of orchard grass with alfalfa produced forage of the best quality, with regard to the content of fibre fractions.The content of the acid detergent fiber and acid detergent lignin fractions and yielding of legume grass mixtures were higher in the forage from plots with slurry than from plots with mushroom. The work reported here was undertaken to determine the effect of spent mushroom substrate (SMS) and cow slurry used in the cultivation of hybrid alfalfa and grass mixtures on plant productivity and dry matter nutritional value. Uncomposted waste left after growing mushrooms (Agaricus bisporus) was used. Additionally, slurry from cows with the milk yield of 6000 to 8000 litters a year was applied; the animals were housed indoors on straw bedding, with manure removed daily. The 3‐yr research study (2013–2015) was conducted in the experimental field, in east‐central Poland. Treatments were replicated three times, with plots of 3 m³ as experimental units in a split‐plot arrangement. In the experiment the main research factors were legume–grass mixtures and organic fertilizers with high organic matter content: SMS and cow slurry, used separately and in various combinations. In the experiment three plant species were involved: Medicago sativa x varia Martyn (alfalfa hybrid) ‘Tula’, Dactylis glomerata (orchard grass) ‘Bora’, and Lolium perenne L. (perennial ryegrass) ‘Info’. These species were grown as three legume–grass mixtures. The results demonstrated that SMS application to legume–grass mixtures increased NDF content in the forage more than slurry. The content of the ADF and ADL fractions and the yields of legume–grass mixtures were higher in the forage from plots with slurry than from plots with SMS. The mixture of orchard grass with alfalfa produced forage of the best quality with regard to the content of fiber fractions.