Changes in Selected Forage Parameters of Meadow Timothy ( Phleum pratense L.) Biomass and in the Soil as a Response to Slurry Interaction with Soil Conditioners

The aim of the research was to assess the effect of slurry and soil conditioners on Phleum pratense yield and its selected parameters and on soil nutrients. The second aspect of the experiment was to obtain information whether slurry and soil conditioners applied together will increase the accumulation of nitrogen, phosphorus and potassium in the soil compared to slurry applied on its own or together with NPK fertilizers. The research was carried out on the basis of a three-year (2015–2017) field experiment. The interaction of soil conditioners or mineral fertilizers with slurry was tested on forage grass of the Meadow timothy species of the Secesja variety, sown in autumn 2014. Grass total protein, crude fiber and crude ash content and net energy concentration (NE) were determined; additionally, at the end of the experiment, total nitrogen, phosphorus and potassium content in the soil was measured. The results of plant material analyses were statistically developed using a three-factor analysis of variance, while the results of soil content determination were developed with a one-factor analysis. The interaction of slurry with Humus Active or Rosahumus significantly increased the amount of meadow timothy biomass in relation to plants fertilized with slurry on its own (by 22% and 26%, respectively) or supplemented with NPK fertilizers (by 9% and 7%). The interaction of slurry with the Rosahumus soil conditioner resulted in a significant increase in meadow timothy crude fiber content compared to the effect of slurry applied on its own or with NPK fertilizers (by 5% and 6.5%). The interaction of slurry with soil conditioners did not result in a significant increase in total protein and crude ash content or in the net energy concentration compared to slurry applied on its own or with NPK fertilizers. Soil nutrient content determined after the experiment proved a significant impact of the interaction of soil conditioners and slurry on the accumulation of nitrogen, phosphorus and potassium.