划破草皮对不同地形高寒草甸草原土壤特征及地下生物量的影响

在青藏高原东缘东祁连山高寒草甸草原开展平地划破草皮和缓坡地划破草皮试验,研究了划破改良措施对土壤特征及地下生物量的影响。结果表明,划破干扰对土壤含水量和土壤紧实度的影响主要体现在7-8月,在此期间划破干扰对平地的改良效果均显著优于缓坡地;划破初期,划破干扰减小了平地与缓坡地划破沟内表层地下生物量,但经过4个月的生长季,划破改良显著增加了平地表层土壤地下生物量,而缓坡地表层土壤地下生物量反而较其对照区有所减小;划破处理可以有效增加平地各个土层有机碳含量,而对于缓坡地,反而降低了表层土壤有机碳含量。研究证实,平地划破草皮措施有利于生产力较低的高寒草甸草原禾草-嵩草草甸的综合改良,但划破草皮措施对以嵩草为优势种的缓坡地草甸草原需谨慎使用。

Effects of sward cleavage on soil characteristics and underground biomass in different terrains of alpine meadows-steppe

The effects of sward cleavage on soil characteristics and underground biomass were investigated in ar-eas of flat terrain and gentle slope terrain located in the eastern alpine meadow-steppe of the Qinghai-Tibetan Plateau.The results showed that the effects of sward cleavage on soil water contents and soil compaction were most significant in July and August,with the treatment’s improving effects during that period being signifi-cantly better for flat terrain than gentle slope terrain.The underground biomass of cut grooved surfaces de-creased in both flat terrain and gentle slope terrains at the beginning of treatment.However,the underground soil biomass in flat terrain soil layers had significantly increased after growing for four months while it had de-creased in gentle slope terrain compared with the control.In addition,soil organic carbon contents in flat ter-rain increased after treatment but decreased on gentle slopes.Our research shows that sward cleavage in flat terrain significantly improves the low productivity of alpine meadow-steppe grasses,but that caution is advised when using this technique on gentle slope terrain.