Abstract: With 1.0×10⁶, 2.0×10⁶,4.0×10⁶, and 8.0×10⁶ cells·mL^-1 of Scenedesmus obliquus as the food of Brachionus calyciflorus, and by using population accumulative culture method and life table demographic approach, this paper studied the effects of S. obliquus density on the population dynamics of B. calyciflorus collected from the Tunxi section of Xin’an River at 25 ℃. The results showed that food concentration had significant effects on the population growth rate and resting egg production of B. calyciflorus. At lower food concentrations (≤4.0×10⁶ cells·mL^-1), the population growth rate and resting egg production of B. calyciflorus were lower and had no differences, while at high food concentration (8.0×10⁶ cells·mL^-1), both the population growth rate and the resting egg production were larger. Food concentration had no significant effects on the mixture rate and fertilization rate of B. calyciflorus. At food concentration 4.0×10⁶ cells·mL^-1, the net reproductive rate and generation time of B. calyciflorus were the highest and longest, respectively. The intrinsic rate of population increase of B. calyciflorus at food concentration 1.0×10⁶ cells·mL^-1 was the smallest, and the average lifespan and life expectancy at food concentration 8.0×10⁶ cells·mL^-1 were the longest.

Key words: cold region, organic matter mulching, soil water content, soil temperature, soil nutrients.