Abstract: Based on soil water controlling experiment conducted in Jinzhou in 2013,the effects of soil moisture and soil temperature on soil respiration of maize farmland in northeast China were investigated under three levels of soil relative water contents (SRW) of 86%,96%,and 105%,respectively.The results indicated that the intensity of soil respiration is influenced by soil moisture condition.Specifically,soil respiration rate decreases with the increasing SRW.Meanwhile,the diurnal pattern and the seasonal dynamic are not impacted by SRW and both show a variation trend of the one-peak curve.The daily and annual maximums of soil respiration rates appear at 11:00-14:00 and in August,respectively.The sensibility of soil respiration to soil temperature in maize farmland is affected by the different levels of soil water controls,which is represented as the daily dynamic of soil temperature at the soil depth of 10 cm lagging behind that of soil respiration and a 5-6 hour lagging of the daily maximum soil temperature relative to the daily maximum soil respiration in August and September.In addition,the positive correlations between soil temperature at the soil depth of 10 cm,15 cm,30 cm,45 cm and soil respiration are respectively significant or extremely significant under different soil moisture conditions and soil respiration has the highest correlation with soil temperature at the soil depth of 45 cm.Besides,under the SRW of 86%,96%,and 105%,soil respiration shows an exponential relationship with soil temperature at the soil depth of 45 cm and soil temperature sensibility indices i.e.Q₁₀ are 1.92,2.20 and 1.72 in the studied area in 2013,respectively.

Key words: Soil respiration, Soil water controls, soil temperature, soil temperature sensibility index, Maize farmland