The administration of large quantities of chemical fertilizers may strongly diminish the plant diversity of semi-natural grasslands. In the Apuseni Mountains (Romania), the chemical fertilization is rarely used, but, considering the population’s decrease and the livestock diminish, this might have a greater importance in the future. The maintenance of semi-natural grasslands within the mountainous landscape depends greatly on fertilization. Our paper’s goal is to assess the influence of mineral fertilizers upon semi- natural grassland’s plant diversity. Mineral fertilizers complex NPK 20:10:10 ratio was applied in three quantities: 50N 25P 25 K, 100N 50P 50K, and 150N 75P 75 K. The large quantities of mineral fertilizers generated a considerable decrease of the plant diversity.

The extensive exploitation of agricultural systems is the factor which created the semi-natural grasslands with large plant diversity. These meadows’ persistence depends in a large extent on the extensive use which can be recognized in the field by the presence of certain species having an indicator value. This paper’s objective is to elaborate a list of indicator species for the extensive use of the semi-natural grasslands in the boreal floor.

The Agrostis capillaris-Festuca rubra’s phytocenosis has a floristic diversity between 20 - 52 species and it is characterised as mesophilous, moderate acidophilous, moderate nitrophilous and medium resistant for mowing, treading and grazing.

Researchers current concerns are to maintain the high floristic biodiversity, enabling sustainable development of natural grasslands in mountain areas. Large surfaces of the Apuseni Mountains are fertilized with organic fertilization (these is the only way of fertilization used by grasslands owners), fact which causes probably the high phytodiversity specific for these area. Grassland management is the one who creates and maintains a high phytodiversity, being able also to reduce it drastically in a short time. This involves research at various levels of intensification in order to determine how productivity and phytodiversity of grassland evolves over time. The first studies conducted in the Apuseni Mountains were aimed to increase production and fodder quality through various technological methods (fertilization with organic fertilizers, amendment, overseeding etc.), without taking into account the specific biodiversity of phytocenosis. Currently the problem is changing radically and in all research actions undertaken is not overlooked the environmental dimension. Through this experience we plan to examine how different doses of organic fertilizers influencing productivity and fitodiversitatea of mountain meadows.

Organic fertilizers have an influence on the floristic composition of grasslands. Fertilizing with manure favours the phytodiversity of grasslands. The objective of the study was to follow the influence of mulching and organic fertilizing in small quantities and at various time intervals upon dry matter yield and phytodiversity of Agrostis capillaris L. - Festuca rubra L. grassland type in the Apuseni Mountains. Seven treatments  ( control  ( mowed 1/year ) ; mulch 1/year; mulch 1/year + 5 t/ha manure /year; mulch 1/year + 5 t/ha manure/2 years; mulch 1/year + 10 t/ha manure/2 years; mulch 1/year + 10 t/ha manure/3 years; abandonment )  were evaluated experimentally. Organic fertilizing in low quantities could be a way to maintain the floristic diversity of oligotrophic grasslands in Apuseni Mountains.