Abstract:

The soil respiration, temperature and moisture under Robinia pseudoacacia plantation in the rocky mountain of north China were investigated. Soil respiration rate was measured with Li-8100, and the temperature and moisture were monitored with AR5 from January to December in 2006The results showed that the diurnal variation of soil respiration rate (SRR) was not remarkable, while the daily and seasonal variation was significant and displayed one single peak curve in the whole year, which basically accorded with the trend of the daily and seasonal variation of the soil temperature. The daily SRR was the lowest with almost unchanged daily from January to March and gradually rose in April, and then rapidly increased in May. It reached a maximum during July, and then decreased until November，when it approximated to that from January to March and didn’t change any longer until the end of December. SRR in the main growth season (April to October) was markedly higher than that in the minor growth season, and they were 3.63 and 0.90 μmol·m^-2 s^-1 respectively. The annual average SRR was 2.50 μmol·m^-2 s^-1. Soil respiration rate was significantly (p<0.01) correlated with the soil temperature at each of the 0, 5，10，15 and 20 cm depth, with the best correlation at 20 cm. The SRR exponentially increased in response to the soil temperature. Q₁₀ was 2.20, 2.28, 2.34, 2.40 and 2.48, respectively, at the above different depths. There was no significant relationship found between SRR and soil water content.

Key words: the rocky mountain in north China, Robinia pseudoacacia plantation, soil respiration