Effects of alpine meadow degradation on soil carbon,nitrogen,phosphorus and correlative enzyme activity
[Objective]Soil carbon,nitrogen and phosphorus are of key importance to alpine grassland ecosys-tem,and alpine meadow degradation can change soil nutrients content and their distribution. Clarifying the effects of alpine meadow degradation on soil key nutrients carbon,nitrogen and phosphorus content and their correlation with enzyme activity can provide a theoretical basis for the restoration of degraded alpine meadows.[Method]Four types alpine meadows,including Fenced (FG) as a control,light degraded (LD),moderate degraded (MD) and serious de-graded (SD) alpine meadow,were selected to study the effects of alpine meadow degradation on soil key nutrients content,correlative enzymes activities as well as correlation of soil key nutrients to enzymes in growing season in the eastern Qilian Mountain area.Soil organic carbon,soil total and available nitrogen,soil total and available phosphorus,soil catalase activity,soil catalase,urease,and alkaline phosphatase activity were analyzed.[Result]Soil carbon con-tents increased after degradation compared with CK except for 10～20 cm depth in LD and 0～10 cm depth in MD,and soil carbon content of 0～10cm in SD was the highest,which was 82.1 g/kg. But soil catalase activity was de-clined after degraded,and it showed the highest in 20～30 cm in FG,the lowest value was in 10～20 cm in LD,the value was 23.35 mg/g and 20.90 mg/g respectively. The degradation resulted in the decrease of soil total nitrogen content,and the increase of available nitrogen content and urease activity. The highest available nitrogen content and urease activity were 649 mg/kg and 3.47 mg/g in SD grassland,respectively.. Urease activity increased in FG and SD,but decreased in MD and SD with the soil depth. The value of urease activity varied from 0.18 g/kg to 0.22 g/kg.Alpine meadow degradation had no significant effect on soil total phosphorus of 0～10cm depth.Soil avail-able phosphorus of LD and MD increased,but SD decreased compared with FG. Soil available phosphorus of LD,MD and SD increased 152％、60％ and-32％ respectively in 0～10 cm dept. Soil alkaline phosphatase activity in-creased under degradation,ranging from 0.52 mg/g to 0.62 mg/g. The correlation analysis showed that soil the cor-relation between organic carbon content and catalase activity was significant in FG,but there was no significant corre-lation in LD and SD.There was no significant correlation between soil nitrogen content and urease activity in FG,but was significant in MD and MD. There was significant correlation between soil phosphorus content and alkaline phos-phatase activity in FG,but was no significant correlation in degraded meadows.[Conclusion]The correlation between soil key nutrients content and enzyme activity was changed after degradation in alpine meadows,and phosphorus addi-tion may be needed in the restoration of serious degraded alpine meadow.
万方数据
维普
