In this study the objective was to determine the changes of the floristic composition under the influence of organic, mineral and organic – mineral fertilizers on the vegetation cover of a hayfield from the hill area of western Romania, respectively Fibiş (Timiş County). In the year 2011 the average of the annual rainfall amount is 484 mm. On the season, the precipitation is rich in summer (30.7%), followed by spring (25.1%), fall (23.9%), and winter with less precipitation (20.3 Soils perdominante in Fibis area are the reddish-brown The experimental field was organized by setting 9 fertilisation variants ( 3 organic, 3 mineral and 3 organic – mineral fertilisation variants) and a control non-fertilised variant. The research plots were set on a homogenous vegetation sector of the hayfield. The fertilisation variants applied were the following: V1 – control;V2-20 t sheep manure,V3-40 t sheep manure,V4-60 t sheep manure,V5-20 t sheep manure+ P50 ;V6-20 t sheep manure+ P50++ K50; V7-20 t sheep manure+ N50 + P50 + K50 ;V8 - N100 + P50 + K50 ; V9 - N150 + P50 + K50 ; V10 - N100+100 + P50 + K50; The plots were set in blocks with ten variants and three replicates, each having a surface of 20 square meters (2m x 5m). The vegetation data were collected using the linear point quadrate method, thus being calculated several vegetation features. After DJUKIC et al., (2008) the manure applied on grassland determinates changes in the floristic composition involving a higher percentage of legumes in comparison with other species and grasses. The vegetation features taken in account were: the botanical composition, the biodiversity (species richness, Shannon and Simpson indexes),). The fertilisation has influenced mainly the biodiversity and the light and soil reaction ecological spectre. In a permanent grassland agro-ecosystem the floristic composition varied depending on substances flow, soil nutrients availability and climatic conditions (MOISUC et all 2001) The floristic composition studies need long time researches, as in the case of biodiversity, to provide sustainable results (DJUKIC et al., 2008)

floristic composition , changes, botanical composition, biodiversity.

Presentation: oral