关键词: 低山丘陵区, 冬小麦田, 土壤呼吸速率

Abstract: Changes and mechanism of soil respiration on winter wheat field in low mountain and hill regions of North China were analyzed.The automatic observation systems Li-8100 and AR5 were used for the measurement of the soil respiration, and soil temperature and moisture respectively. The main results were as follows: (1)The soil respiration rate(SRR) on clear or cloudy day was markedly higher than that on overcast day before and after reviving. The diurnal variations of SRR were both demonstrated single-peak curve in clear or cloudy day and overcast day. (2) The SRR maintained at a relatively low level before reviving. While it increased rapidly after reviving,reached a peak during grain filling and decreased after harvest. The average SRR was 1.28μmol·m-2s-1 for the whole growing period, 0.63μmol·m-2s-1before reviving, and 2.18μmol·m-2s-1after reviving. (3) Significant relationship were found between SRR and soil temperatures at different depths (the surface, 5cm depth, 10cm depth, 15cm depth and 20cm dept, p<0.01), which could be best described by exponential equations,and the best was at 20cm.The Q10 of winter wheat from soil surface to 20cm depth were 2.09, 2.29, 2.39, 2.51and 2.63. Excessively low soil water content would restrain SRR. SRR was mainly affected by soil temperature, not significantly related to soil water content when it was at 20%-30%.

Key words: Low mountains and hills, Low mountains and hills, Winter wheat field, Soil respiration rate