刈割耙除对草地土壤呼吸的影响

以中国北方退化天然草地为研究对象,测定草地刈割耙除处理后土壤温度、含水量和土壤呼吸,探讨土壤温度、含水量和土壤呼吸的变化规律及对刈割耙除的响应,并利用根空斑/根排除法测定了草地根空斑呼吸,为草地的恢复实践提供理论基础。结果表明:刈割耙除处理后草地生长季节土壤温度升高,处理组地表、地下5 cm、地下10 cm、地下15 cm和地下20 cm平均温度达到21.39,18.55,18.29,17.94和17.44℃,高于对照组的19.85,17.20,16.95,16.59和16.43℃,其中地表及地下15 cm温度显著高于对照样地(P＜0.05)。刈割耙除后草地土壤含水量降低,处理组土壤0~10 cm,10~20 cm和20~30 cm含水量分别达到7.33%,8.15%和8.56%,显著低于对照样地的10.33%,10.74%和12.22%(P＜0.05)。刈割耙除使8月中下旬草地土壤呼吸显著降低(P＜0.05),但对生长季其余时间的土壤呼吸无显著影响。对根空斑呼吸的研究表明,试验地土壤中根呼吸和微生物呼吸之比为1∶3。因此,刈割耙除处理能够提高草地土壤温度,降低土壤含水量,但对7月和9月草地土壤呼吸无影响。

Effect of Raking on Grassland Soil Respiration

Changes of soil temperature, moisture and respiration under raking management were investigated in order to know how grassland management impact grassland ecosystem. Results were as follows: compared to CK, the soil temperatures of raking management in 0, 5, 10, 15 and 20 cm depth were increased and were higher than that of CK, respectively. Specifically, the soil temperatures of raking management in 0 cm and 15 cm depth is significantly higher than that of CK(P＜0.05). Compared to CK, raking management decreased 0~10 cm, 10~20 cm and 20~30 cm layer soil moisture into 7.33%, 8.15% and 8.56% which were significant lower than that of CK(P＜0.05), respectively. The soil respiration of raking management in mid and late August was significant lower than that of CK, but there were no significant differences for the remaining growth season. The study of rootless gap respiration showed that the rate of root respiration and microbe respiration was 1∶3. Raking could increase grassland soil temperature, decrease soil moisture, but not significantly affect soil respiration in July and September.