Abstract: With the equipments simulating the environment in a ruminant's paunch the in vitro fermentation of ruminal microbial flora was performed to study the influence of major ecological conditions on crude fibre resolvability. It shows that the crude fibre resolvability is the strongest at the temperature of 30～40℃, stirring intensity of 60～72 r·min^-1 with 20 min·h^-1 and C/N of 10/1 in culture medium. The fibre resolving rate may reach 36～41% after five days of fermentation.

Key words: Ruminal microbial flora, Ecological condition, Crude fibre resolvability, lime concretion black soil, microorganism, winter-wheat/summer maize multiple cropping system, enzyme, tillage, nitrogen