氮添加对晋西北风沙区人工柠条林叶经济谱的影响OACHSSCD

The aging of artificial Caragana korshinskii forest in northwest Shanxi province is serious,while the effectiveness of traditional stubble rejuvenation measures gradually decreases with increasing years.In the context of global nitrogen deposition,it is crucial to study the response of leaf economic spectrum of C.korshinskii to nitrogen application to explore new rejuvenation mechanisms.This study took 18a,22a,and 3a Caragana korshinskii with stubble from 22a plants in the northwest of Shanxi province as the research objects,three treatments were set up:control(CK:0 g N m-2a-1),low nitrogen(N1:8 g N m-2a-1),and high nitrogen(N2:16 g N m-2a-1),to explore the response patterns of leaf economic spectrum traits from aged and stubble C.korshinskii to nitrogen addition.The results showed that:(1)The plasticity and variability of traits differed under nitrogen addition,with acquisitive traits being higher than conservative traits.(2)Nitrogen addition promoted an increase in acquisitive traits and a decrease in conservative traits of C.korshinskii.The 18a plants showed greater sensitivity to the N2 treatment,with leaf area,leaf nitrogen content,and chlorophyll increasing significantly by 18.69％,16.12％,and 7.54％,respectively,and leaf dry matter content decreasing significantly by 10.49％.The 22a plants responded more positively to the N1 treatment,with significant increases in leaf area and specific leaf area of 12.47％and 15.37％,respectively,and a significant decrease in leaf mass per area of 14.05％.In contrast,the 3a after stubble plants showed a weaker response,with only chlorophyll increasing of 17.03％under the N1 treatment(P＜0.05).Stubble significantly influenced specific leaf area,leaf nitrogen content,leaf mass per area,and leaf dry matter content,whereas the interaction between nitrogen addition and stubble only significantly affected leaf area.(3)The leaf economic spectrum phenomenon in C.korshinskii persists under nitrogen addition,with strategies diverging based on nitrogen concentration.The N1 treatment shifted aged plants toward a"fast investment-return"strategy,whereas the N2 treatment resulted in a strategy intermediate between"slow"and"fast investment-return".In summary,nitrogen addition can reverse the survival strategy of aged C.korshinskii by altering leaf economic spectrum traits,but its positive effects on stubble plants are relatively limited.These findings provide theoretical support for the restoration of degraded vegetation in the wind-sand region of northwest Shanxi province under global change.