Few systemic assessments have evaluated the success of these afforestation programs in alpine semi-arid desert ecosystems in the Qinghai-Tibet Plateau. In this study, we investigated the influences of three Salix cupularis plantation age classes (6 yr, 18 yr and 34 yr) on the carbon (C), nitrogen (N), and phosphorus (P) storages and stoichiometry of the soil-plant ecosystem. The consequences of
... [Show full abstract] S. cupularis plantation induced soil spatial heterogeneity. The soil-plant ecosystem C storage increased after the plantation. The N storage showed an increasing trend from 6 yr to 18 yr and then slightly decreased. The P storage presented a continuously declining trend. The result indicated that the imbalance in soil N, P, C occurred with plantation age because of the imbalance of their inputs. The N and P uptakes from subsoil and redistribution to topsoil by S. cupularis may contribute to meet N and P demands for the understory plants. Leaf N:P ratios varied from 8.3 to 17.5. These results imply that N and P status are the main factors limiting plant growth in the alpine-cold desert ecosystem. Thus, we recommend adding N and P fertilizers during plant growth.