Rational use of long fallows in conditions of II uplowland terrace of Lena river

In uplowland terraces of the Central Yakutia overgrowth of a long fallow begins with a phase of tall grasses vegetation: such as Artemisia jacutica (Drob.), Lappula squarrosa (Retz.), senecio jacobaea L. Expenses of seeds stock make 1241 pieces on 1 sq.m. The greatest quantity of shoots fall on 3-4 years of a long fallow due to the seeds of Artemisia jacutica (Drob.) and small seeded plants (Draba nemorosa L., Androsace lactiflora Pall.). On 4-5-й year of a long fallow participation of Artemisia jacutica (Drob.) in structure of herbage essentially decreases, dominates Leymus chinensis (Trin).Tzvel. On years at mowing a herbage the output of biomass decreases with 2,6 up to 1,4-1,7 t/hectares. Carrying out of mineral matters due to mineralization of organic substances in a phase of tall grasses long fallows is high. On N makes 70 kg/hectares, on P2O5 - 20 kg/hectares, on K2O - 200 kg/hectares and on СаСО3 - up to 50 kg/hectares. For grassland establishment of a long fallow multicomponent grass mixtures from the zoned grades are recommended. An optimum grass mixture for grassland estab-lishment is 4 componental with Psathyrostachys juncea (Fisch.) Nevski, Medicago falcata L. and lu-cerne.