Effects of nitrogen and silicon application on leaf nitrogen content and net photosynthetic rate of Elymus nutans in alpine meadow

AimsElymus nutans is one of the dominant plant species in alpine meadow. Purpose of this research was to study the effects of nitrogen and silicon application on leaf nitrogen content and net photosynthetic rate in this species to provide scientific basis for fertilization practice in alpine meadow.MethodFour levels nitrogen combined with four levels silicon was applied to E. nutans plants in the alpine meadow. Leaf nitrogen content and net photosynthetic rate of E. nutans were measured.Important findings The results showed that there was a significant improvement in leaf nitrogen content and net photosynthetic rate of the E. nutans with nitrogen or silicon application alone; However, there was a significant interaction between nitrogen and silicon treatments on leaf nitrogen content and net photosynthetic rate; Combining with the three different levels nitrogen, low level silicon (Si₁) application did not increase leaf nitrogen content and net photosynthetic rate, but middle level silicon (Si₂) could significantly increase the leaf nitrogen content; Combining with the low (N₁) or middle (N₂) level nitrogen, middle level silicon (Si₂) application could significantly increase the net photosynthetic rate; Compared with that control without fertilization, the middle level nitrogen combined with the same level silicon treatment had the highest average of leaf nitrogen content and net photosynthetic rate, which increased by 119.99% and 85.70%, respectively. This study indicated application of nitrogen combined with silicon application enhanced leaf nitrogen content and net photosynthetic rate of E. nutans, and 8 g·m^-2silicon application had the best result among other treatments.