关键词：
biological activity in soil;broadleaves;carbon-nitrogen ratio;coniferous forests;forest plantations;forests;mixed forests;nitrate;nitrate nitrogen;nitrogen;nutrients;organic carbon;phosphorus;soil degradation;soil depth;soil fertility;soil organic matter;trees;Alnus;Cunninghamia lanceolata;Kalopanax septemlobus;China;Hunan
摘 要：
An investigation on soil organic carbon, total N and P, NO3--N, available P, microbial biomass C, N and P, basal respiration and metabolic quotients (qCO2) was conducted to compare differences in soil microbial properties and nutrients between 15-year-old pure Chinese fir (Cunninghamia lanceolata) and two mixed Chinese fir plantations (mixed plantations with Alnus cremastogyne, mixed plantations with Kalopanax septemlobus) at Huitong Experimental Station of Forest Ecology (26 degrees 45'N latitude and 109 degrees 30'E longitude), Chinese Academy of Sciences in May, 2005. Results showed that the concentrations of soil organic carbon, total N, NO3--N, total P and available P in mixed plantations were higher than that in pure plantation. Soil microbial biomass N in two mixed plantations was averagely higher 69% and 61% than that in pure plantation at the 0-10 cm and 10-20 cm soil depth, respectively. Soil microbial biomass C, P and basal respiration in mixed plantations were higher 11%, 14% and 4% at the 0-10 cm soil depth and 6%, 3% and 3% at the 10-20 cm soil depth compared with pure plantation. However, soil microbial C:N ratio and qCO2 were averagely lower 34% and 4% in mixed plantations than pure plantation. Additionally, there was a closer relation between soil microbial biomass and soil nutrients than between basal respiration, microbial C:N ratio and qCO2 and soil nutrients. In conclusion, introduction of broad-leaved tree species into pure coniferous plantation improved soil microbial properties and soil fertility, and can be helpful to restore degraded forest soil.
