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Field trials on the improvement of degraded pastures by over seeding of perennial forages were conducted in 2004-2006 in Ikh tamir, Arkhangai (High Mountain), Shaamar, Selenge (forest steppe) and Argalant, Tuv (steppe). 1 ha of degraded pasture area was fenced in each soum and field observations conducted to select forage species suited to improvement of degraded pasture, develop appropriate techniques for over seeding and determine right time of over seeding.
Though the seedlings were dried off due to hot conditions in July, August there is still a possibility that over seeding can work especially when the climatic conditions are favorable. The seeds over seeded in the heavily overgrazed pastures always germinated to some extend.
Like in the two previous years no definite results were achieved this year regarding the field experiments on improvement of degraded pasture by over seeding of forage perennials. Medicago seeds germinated in all regions but most seedlings died not establishing good root system due to high air temperature in July - August, shortage of soil moisture and soil compactness. Few individual seedlings are left for wintering but next year development of seedlings stops not achieving filleting stage. Seeds of Medicago and grasses germinate well in the plots treated with "over seeding followed by animal trampling" and "sowing in rows". However, the regrowth stagnated next year. Relatively higher number of germs and seedlings left for wintering was observed in plots sown in rows in late autumn or early spring in High Mountain and steppe areas. Field germination rate, growth and viability of seedlings were relativity good in 2006 with good rainfall.
The 3 years field trials show that the improvement of already degraded pasture land by over seeding of perennial forages is a not easy task. Improvement of overgrazed pastures by over seeding is very risky and is a time, capital and labor consuming procedure. In order to achieve a better contact of the seed with the soil, it is better to use "over seeding followed by livestock trampling" in the early spring when the snow melts and the soil surface becomes moist enough. However, it is needed to test this treatment in connection with the density of the resident vegetation and degradation rate of the pasture.
There is an urgent need to improve pasture utilization and to increase the awareness of herders in order to use the possibility of natural rehabilitation of pasture before extreme overgrazing has occurred. On the other hand, some attention should be given to the introduction of seeds of species well adapted to a particular region. So, some changes in species seeds of which to be over seeded can occur in 2007.
For the last years USA and Russia have widely used the technology for making soil surface layer thin to establish good contact of seeded seed with the soil. Technology for sowing into stripes with wider rows establishing micro relief by making a groove is also used. These countries prefer to use native forage species for reseeding. All these factors could be considered in the field trials on over seeding for the next year.