In this study the objective was to determine the effects of mineral and organic – mineral fertilizers on the production of a hayfield from the hill area of western Romania, respectively Fibiş (Timiş County). The average of the annual air temperature in this region is 10.7 o C and the average of the annual rainfall amount is 608 mm. The climate in the studied area is temperate continental with Mediterranean influences. The experimental field was organized by setting 9 fertilisation variants (3 mineral,3 organic and 3 organic – mineral fertilisation variants) and a control non-fertilised variant.One of the most important maintenance works needed in grasslands is represented by fertilization. Every type of grasslands has different fertilisation needs, so the importance of this research is to set the optimal fertilization rate with for different types of fertilizing(mineral, organic and mixed). Every fertilisation experience is organized in ten variants and three replicates.  The permanent grasslands is visibly influenced by fertilisation starting with the first year from the fertiliser application . The methodology used focuses on the principle of restitution of nutrients exported with the harvest, and based Bossingaul principle formulated by Justus von Liebig in XIX century and refers to the fact that culture plants consuming nutrients in the soil for crop depletes soil formation in those elements that are removed from the surface with crop, resulting in time reduce soil fertility. It appeared, therefore the necessity to return soil nutrients. The numerous researches show that applying fertilisers on grasslands is justified economically since, on the average, 1 kg of active element results in an increase of 80-100 kg of green matter. This economic productivity is also strengthened by the fact that from 1 ton of dried matter we can extract 20-21 kg of N, 6-8 kg of P 2 O 5 , 20-21kg of K 2 O and 10-14 kg of CaO. As a conclusion, we can say that fertilising grasslands results, on the average, in a twofold to threefold increase of the yield.

mineral, fertilisation, organic ferilisation, production, sheep manure

Presentation: oral