Abstract: Black soil samples were collected from Lishu (43°20′ N, 124°28′ E), Dehui (44°12′ N, 125°33′ E), Hailun (47°26′ N, 126°38′ E), and Bei’an (48°17′ N, 127°15′ E), and an incubation test was conducted to study their microbial respiration and Biolog metabolic functional diversity at 4 ℃, 15 ℃, and 28 ℃. The soil microbial respiration rate was in the order of Bei’an >Hailun >Dehui >Lishu, irrespective of incubation temperature, but the sensitivity of the respiration to the temperature, i.e., Q₁₀ value, differed. The average value of the Q₁₀for the soils from Lishu, Dehui, Hailun, and Bei’an was 2.72, 3.26, 3.21, and 3.74 in the range of 4 ℃-15 ℃, and was 3.29, 2.36,2.11, and 1.79 in the range of 15 ℃ to 28 ℃, respectively. The metabolic quotient (qCO₂) also differed with incubation temperature, which was in the order of Lishu > Dehui > Bei’an > Hailun at 28 ℃ and of Bei’an > Dehui > Hailun > Lishu at 15 ℃, but no significant difference was observed at 4 ℃. Biolog test showed that the substrate richness and metabolic Shannon diversity index of microbial community were higher for the soils from Hailun and Bei’an at 4 ℃, but higher for those from Lishu and Dehui at 15 ℃ and 28 ℃. Principal component analysis with Biolog data suggested that the metabolic function of soil microbial community was similar between Bei’an and Hailun, and between Dehui and Lishu. In sum, the responses of black soil’s microbial respiration and community functional diversity to temperature varied with latitude, i.e., more sensitive to low temperature in high latitude region, but more sensitive to high temperature in low latitude region.

Key words: black soil, soil respiration, Q₁₀ value, microbial metabolic quotient, Biolog, dairy effluent irrigation, winter wheat  summer maize rotation, grain yield, phosphorus utilization efficiency.