EFFECT OF APPLICATION OF DIFFERENT AMOUNTS OF NITROGEN AND STAGES OF PLANT DEVELOPMENT AT CUTTING ON YIELD AND FORAGE VALUE OF GRASSLANDS

Abstract

Grasslands in Bosnia and Herzegovina account for over 50% of the total agricultural land. However, although grasslands occupy large areas they are not optimally used. Inadequate use without the application of nitrogen fertilizer as well as cutting in the late stages of plant development have a negative impact on producing good quality forage and achieving high and stable yields. As the quality of biomass and grassland productivity largely depend on soil fertility, botanical composition, and stage of plant development at cutting, the aim of the research was to determine the influence of the application of different amounts of nitrogen fertilizer and the stage of plant development at cutting on dry mass yield, crude proteins and grassland microbial activity.
The results of the research show that the stage of plant development at cutting and the application of different amounts of nitrogen have a significant impact on the dry mass and crude protein yields. The dry matter yield ranged from 7.54 t ha^-1 in the N0 variant (grass earing stage) to 13.19 t ha^-1 in the N90 variant (grass flowering stage). Cutting at the grass earing stage can produce a considerably higher amount of good quality forage mass from the grassland, as well as the application of 70 to 90 kg ha^-1 of nitrogen.