温度对杉木林土壤呼吸的影响(英文)

Soil samples collected from the surface soil (0(10 cm) in an 88-year-old Chinese fir (Cunninghamia lanceolata) forest in Nanping, Fujian, China were incubated for 90 days at the temperatures of 15°C, 25°C and 35°C in laboratory. The soil CO2 evolution rates were measured at the incubation time of 2, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80 and 90 days. The results showed that CO2 evolution rates of soil samples varied significantly with incubation time and temperature during the incubation period. Mean CO2 evolution rate and cumulative amount of CO2 evolution from soil were highest at 35°C, followed by those at 25°C, and 15°C. Substantial differences in CO2 evolution rate were found in Q10 values calculated for the 2nd and 90th day of incubation. The Q10 value for the average CO2 evolution rate was 2.0 at the temperature range of 15-25°C, but it decreased to 1.2 at 25- 35°C. Soil CO2 evolution rates decreased with the incubation time. The cumulative mineralized C at the end of incubation period (on the 90th day) was less than 10% of the initial C amounts prior to incubation.     

母猪产后瘫痪的原因及防治措施

母猪产后瘫痪是一种代谢病,在饲养管理粗放、饲料条件较差等情况下极易发生。该病发生后,不但影响母猪的利用价值,而且也影响仔猪的质量,给养猪生产造成很大的损失。本文结合实践,对发病原因、症状和防治措施作浅述。