[The temporal variations of soil respiration under different land use in Liupan Mountain forest zone].

The temporal variations of soil respiration under cropland, rangeland, natural secondary forest (brushwood, nature secondary forest dominated by Querces liaotungensis koiz or Populus davidiana dode) and the plantation of larch (13, 18 and 25-year-old Larix principis-rupprechtil mayr) in Liupan Mountain forest zone was studied. It was found that the rate of soil respiration increased with increasing soil temperature during diurnal variation and the highest temperature was from 13:00 o'clock to 15:00 o'clock, the lowest temperature was from 04:00 o'clock and 08:00 o'clock, the variation of soil respiration rate appeared same trend. The daily rate of soil respiration increased from May to October and which was the highest from August to September and declined on October.