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明确土地利用方式变化对土壤呼吸速率的影响,对预测黄土区退耕还草条件下的土壤碳循环变化具有重要的意义.于2010年7月～2011年12月,利用Li-8100系统(Li-COR,Lincoln,NE,USA)监测黄土高原沟壑区塬坡上相邻农田和草地的土壤呼吸速率,用以验证不同土地利用方式是否导致土壤呼吸速率的变化.结果发现,土地利用方式的改变导致了土壤呼吸速率的显著(P<0.05)变化,试验期间草地平均土壤呼吸速率[1.67μmol·(m2.s)-1]较相邻农田[1.35μmol·(m2.s)-1]提高24%(P<0.05),累积土壤呼吸草地(856 g·m-2)较农田(694 g·m-2)提高了23%(P<0.05).农田与草地的土壤温度差异显著,草地平均土壤温度(14.9℃)较农田(12.4℃)高2.5℃(P<0.05).农田和草地生态系统土壤温度与土壤呼吸均呈显著的指数关系(P<0.000 1).但农田和草地生态系统中土壤呼吸对温度响应存在本质差异(α=0.05),农田土壤呼吸的Q10(2.30)高于草地(1.74).土壤温度能够很好地解释农田和草地生态系统之间土壤呼吸的差异.
To clarify the effect of land use change on soil respiration rate is of great significance for predicting the soil carbon cycling under the conditions of returning farmland to grassland in the Loess Plateau. From July 2010 to December 2011, Li-8100 system (Li- COR, Lincoln, NE, USA) to monitor the soil respiration rate of adjacent farmland and grassland on the slope in the gully region of the Loess Plateau to verify whether different land use patterns lead to the change of soil respiration rate. The results showed that the change of land use pattern resulted in The soil respiration rate was significantly (P <0.05) higher than that of the adjacent farmlands [1.67 μmol · (m2.s) -1] compared with [1.35 μmol · (m2.s) -1] (P <0.05), and the cumulative soil respiration of grassland (856 g · m-2) was 23% higher than that of farmland (694 g · m-2) The soil temperature (14.9 ℃) was 2.5 ℃ higher than that of farmland (12.4 ℃) (P <0.05) .The soil temperature and soil respiration of farmland and grassland ecosystem showed a significant exponential relationship (P <0.000 1), but the farmland and grassland ecosystem Soil respiration had an essential difference in response to temperature (α = 0.05), Q10 (2.30) in farmland soil respiration was higher than that in grassland (1.74) Soil temperature can well explain the differences in soil respiration between farmland and grassland ecosystems.