翻耕对半干旱区高寒草甸地表水热条件的影响

通过对青藏高原东北缘半干旱盆地退化高寒草甸地表观测资料的分析，研究了土壤含水量、地表温度和植被盖度之间的相互关系，分析了翻耕所导致的地表植被破坏和土壤属性的变化对高寒草甸的影响。结果表明:1）较高植被覆盖区域内土壤含水量较高；2）降水后，较低植被覆盖区域内地表温度较低，地表蒸散量较大；3）在长时期缺乏降水的情况下，较低植被盖度区域内地表温度较高，土壤含水量偏低。以上结果说明，翻耕后导致的地表植被破坏和土壤属性变化，会导致翻耕区内地表蒸散偏大，更容易出现土壤水分不足的现象，不适合半干旱区高寒草甸群落的恢复。因此，采取增加灌溉或者免耕补播等不破坏地表植被的补播方式，可能更适合该地区内的植被恢复。

Effects of tillage on surface moisture and temperature of alpine meadow

Effects of tillage on the degraded alpine meadow in a semi arid basin on the northeast ridge of the Qinghai Tibetan Plateau were studied by investigating the relationships among soil moisture, surface temperature and fractional vegetation cover. The results showed that 1) areas with higher vegetation cover had higher soil moisture; 2) after rainfall, the surface temperature of areas with lower vegetation cover was lower; 3) after drying of several days, the surface temperature of areas with higher vegetation cover was lower. Our results indicated that changes of vegetation cover and belowground soil structure by tillage would cause quick loss of soil moisture in this area, which makes it harder for the degraded alpine meadow to recover. Measures, e.g. irrigation and no till sowing, might be suitable alternatives for vegetation recovering of this region.