Age structure of Leymus chinensis populations in different soil substrates on the Songnen Plain

Leymus chinensis is a perennial grass forage of hi gh quality. Age structures of populations in different soil substrates in the mi ddle of May during the vegetative period were studied on the Songnen Plain of Ch ina. There were three age classes of tillers, ages 1, 2 and 3. The populations a ll showed increasing age structures. Tillers of ages 1 and 2 were extremely domi nant, accounting for 89.4% ～99.7%, while age 3 tillers only accounted for 0. 3 %～10.6%.The rhizome age structures of all the populations were made up of ages 2 , 3, and 4. Age 2 rhizomes were the longest and heaviest, followed by age 3, and the proportion of age 4 rhizomes was very small. Rhizome reserves declined with increasing age. The high proportion of investment into young tillers and rhizom es is an effective ecological countermeasure to enlarge the population's living space.