PRODUCTION TRAITS OF MAJOR TYPES OF GRASSLANDS IN THE DURMITOR AREA

Research was done on three localities in the area of Durmitor mountain with the aim to determine the production potential, primarily floristic composition and yield of important types of mountain grasslands (Nardetum strictae, Agrostidetum vulgaris and Poetum viollacea). Natural grasslands in this area are of special importance, because their share in the total agricultural area is above 90% and they are often the only source of fodder for ruminants. Although Durmitor is a habitat of many plant species, including some endemic, these grasslands have a simple to semi-complex floristic composition, mostly due to the competitiveness of leading plants. The share of grasses and herbaceous plants in the fresh biomass of fodder is over 61-68%, legumes 3-6%, and plants of other families 29-33%. The highest yield at all localities was obtained on grassland of the Agrostidetum vulgaris type (7.74 9.81 t/ha -1 ), and the lowest on Nardetum strictae 5.72 6.94 t/ha -1 of fresh fodder. Although most of these grasslands are significantly degraded, their production characteristics can be significantly improved by applying appropriate agricultural techniques and if they are regularly used.


INTRODUCTION
Improving the production of animal feed in the mountainous area of Montenegro is a constant aspiration and goal, but without sufficient commitment to achieve the expected results. The production resource of natural grasslands is one of the most important potentials for development of livestock production in rural areas, where grasslands share in the total agricultural area are above 90% (Dubljević, 2009). Hay and pasture are the basic, and often the only fodder with a smaller share of grain and concentrated feed. Bearing in mind that the grasslands potential is a base for ruminant nutrition, a very significant reduction of the livestock population directly affected the condition and degree of use of meadows, and especially pastures in the wider area of Durmitor mountain.
In an effort to reactivate these areas by returning to the countryside, some measures of agricultural policy are trying to stimulate production, primarily livestock. To meet such efforts, this research was conducted with the aim to contribute the determination of the production potential of mountain natural meadows, which have already been significantly degraded due to poor use and the absence of the care of swards.
In the earlier period, with a much larger number of heads of ruminants, the meadows were fertilized with manure, what resulted in good yields and positive changes in the floristic composition. Bearing in mind that there is almost no manure in this area nowadays, it would be necessary to apply mineral fertilizers, especially on swards that will not be in the system of organic livestock production. Rational fertilization improves the production characteristics of swards, primarily yield, nutritional value and floristic composition (Dubljević, 2005(Dubljević, , 2007(Dubljević, , 2010Vučković et al., 2007;Grubišić et al., 2011;Stoycheva et al., 2016). The authors emphasized the high degree of degradation of mountain grasslands in other areas of similar natural conditions, but also the relation to that resource. There is a real need to work on improvement of the characteristics of mountain grasslands, especially meadows, in the coming period, but also the obligation to apply the measures to preserve the state of the environment.
Durmitor mountain plateau (Jezersko-sinjajevinska and Planinsko Pivska area) is an area that abounds in meadows and pastures of very different potential and accessibility. In the recent time, most of these areas have not been used due to the drastic reduction of livestock in mainly abandoned rural areas or villages.

MATERIAL AND METHODS
Study of production characteristics of more important types of natural meadows in the Durmitor area was performed on the territory of the municipalities of Žabljak (Kovčica, locality B-1), Plužine (Pišče locality B-2) and Šavnik (Donja Bukovica locality B-3). These localities are at the altitude as follow: B-1 1500 m; B-2 1650 m and B-3 1250 m.
The study of vegetation and classification of grasslands was performed using the Braun -Blanquet method. The selected types of grasslands that are the subject of these studies were determined on the basis of previous research (Kovačević, 1969;Dubljević, 2005Dubljević, , 2007Stešević and Caković, 2013;etc.), their distribution and overall importance for livestock production in this area.
Sward productivity was determined by mowing and measuring fresh fodder from 1m2 plots (4 x 1 plots for each grassland variant) (3 localities x 3 grassland types). Dry matter content was determinated by the gravimetric method according to AOAC (2000). Yield analysis was performed on the basis of weight participation of grasses, legumes and herbaceous plants or herbs (plants of other families -Ranunuclaceae, Apiaceae, Scrophulariaceae, Asteraceae, Lamiaceae, Rubiaceae) in the total yield of fodder.
In the whole area, which is under the influence of a harsh mountain climate, specific orographic and edaphic factors, (very dynamic relief), several plant communities have been formed on different lands, with similar and sometimes quite different properties. Kovačević (1969), examining the grassland communities of the wider area of Durmitor moutain, identified the following groups: A -Mountain grasslands: (Goleti and Rudine in the local language) B -Hilly -mountain grasslands C -Mountain heaths D -Hilly grasslands E -Wetlands Three main grassland communities or types: Nardetum strictae (A-1), Agrostietum vulgaris (A-2) and Poetum violacea (A-3) were identified as the variants of the most represented meadow communities in this area. However, the other grassland communities (Festucetum vallesiaca, Brometum erecti, Plantagietum carinata, Festucetum rubrafallax) are also important but not considered in this research due to the fact that they have a rather complex floristic composition.
Statistical analysis encompassed the calculation of basic statistical parameters. The statistical significance of the results for grassland biomass and DM in different grassland communities (factor A) and at different location (factor B) was tested by ANOVA using LSD test. In statistical analysis of data program Statistica 10 was used.

Meadow types and their botanical features
The wider area of Durmitor mountain is characterized by quite complex meadow-pasture vegetation, but the larger meadow complexes closer to the settlements (villages or 'katuns'mountain settlements) are dominated by types of Nardetum strictae, Agrostietum vulgarisi, Poetum viollacea, but their transitional forms created by human influence (fertilization, organized exploitation, etc.) are also significant.
The Nardetum strictae type Grasslands of the Nardetum strictae type are dominant in the study area (table 1), where they consist almost half of the total grassland. They have a simple floristic composition, changed very slowly, and considered the most difficult for land reclamation. The leading species Nardus strictae is a plant with very modest production characteristics (composition, yield and nutritional value), but due to its good cover and firm and compacted sod, it protects the soil well from erosion, even on higher slopes.
The formation and spread of this type of grassland was mostly influenced by unfavorable natural conditions, which limited the development of better species and their communities, but also man, by poor management. Vegetation of non-fertilized grassland type Nardetum strictae is high of about 20 cm in average, achieves low yields and poor nutritional value of forage. The condition is better on periodically and constantly fertilized surfaces, where desirable changes in the floristic composition present. In the earlier period, a good part of these grasslands was used for grazing, while in recent times they have been almost completely abandoned due to the reduction of livestock.
The Agrostidetum vulgaris type Agrostis vulgaris is one of the most widespread plant species on grasslands of various areas and habitats, especially in mountainous but also in lower areas (Mijatović, 1972). This plant is part of several associations, but also builds its own, which is one of the best for livestock production in the less favorable natural conditions of the Durmitor area.
The community Agrostidetum vulgaris in the area of Durmitor (table 2) is most often of anthropogenic origin, because it was formed by changes in the floristic composition of more dominant grasslands (Nardetum strictae) caused by regular fertilization and exploitation. For a long time, due to the situation in livestock sector, these grasslands have been exposed to a strong process of degradation, because there are no measures of their improvement. Less valuable grasses and vegetables are increasingly present in the plant cover, with an increasing share of worthless and harmful species.  Meadows of the type Agrostidetum vulgaris are characterized by a more complex plant cover, average height of about 30-40 cm, of very good cover (95 -100%). In competition with other swards in this area, it gives the highest yields of hay of satisfactory quality.
The Poetum violacea type Meadows of the Poetum violacea type (table 3) cover slightly lower flat terrains with a smaller slope, where the soils are slightly deeper and wetter. They are more of a climatogenic than anthropogenic origin, which can be seen in their maintenance, despite the unfavorable environmental conditions and complete neglect. Belongs to the better meadows of this area, especially on unfertilized areas, thanks to the higher fertility of the land it covers.
These grasslands have a slightly more complex plant cover than the Nardetum strictae type, with an average height of about 30-40 cm. They give medium yields of satisfactory quality, especially with earlier mowing. They are characterized by a very high degree of cover, so since they cover terrains with a smaller slope, there is almost no soil erosion on them.

Yields of grass biomass and dry matter
The results of measuring the yield of fresh grass and dry matter of the examined types of grassland by localities are given in Table 4. The highest average yields at all localities were in meadow type Agrostidetum vulgaris, namely 7.74 t/ha -1 (B-1), 8.86 t/ha -1 (B-3) and 9.81 t/ha -1 (B-2), and the least one in type of Nardetum strictae, 5.72 t/ha -1 (B-1), 6.47 t/ha -1 (B-3) and 6.94 t/ha -1 (B-2). The average yield of variants A-2 was significantly higher compared to variants A-1 and A-3.
Apart from the variants (types of grasslands), differences in yield were also achieved by localities. At sites B-2 and B-3, the yields of fresh fodder of all variants were significantly higher than the yields at site B-1.
Similar yields of fresh forages were obtained by Mijatović (1972), Dubljević (2003, 2010, Vučković et al. (2007), on non-fertilized grasslands of the type Nardetum striktae, Agrostidetum vulgaris and Poetum viollacea. In addition to the yield, Radonjić et al. (2019) in their research emphasized the influence of pasture feed composition on the quality of dairy products. Table 5 shows the share of grasses, legumes and plants from other families (PFOF) in the total yield of green fodder by variants and localities.
Tab. 4 Yields of fresh grass biomass and dry matter (t / ha -1 ) Type    In all types of grasslands, in all localities, the average share of the grasses in the grass biomass was the highest in type A-1(68%), followed by type A-3 with 64% and 61% in type A-2, while the least was in legumes, 4-7%. The share of plants from other families was 29 -33%.

CONCLUSIONS
Based on the results of the research of the production potential of important types of grasslands in the area of Durmitor mountain, the following conclusions can be drawn: -The wider area of the slopes and foothills of Durmitor represents a large, but insufficiently used potential for the development of livestock production.
-The highest average fresh grass yields were in the meadow type of Agrostidetum vulgaris 8.85 t/ha-1, and the lowest in Nardetum strictae 6.47 t/ha-1 of green fodder.
-The average share in the total yield of fresh biomass was 61 -68% of grasses, 3 -6% of legumes and 31 -33% of the other plant families.