The Influence of Plantation on Soil Carbon and Nutrients: Focusing on Tibetan Artificial Forests

As terrestrial ecosystem carbon (C) sinks, plantation ecosystems play essential roles in species diversity protection, resource supply and climate change. Artificial afforestation is of great important in improving the ecological condition, economic development and production in Tibet. Forests can improve soil property changes, yet the understanding of how plantations influence soil C and nutrient conditions in Tibet is still insufficient. This review combines with previous studies to explore the characteristics of soil nutrients, involving nitrogen (N) and phosphorus (P) on Tibetan poplar plantations. Generally, plantations have better abilities in improving the soil C and N cycles, and enhancing the soil stability. In this review, we further analyze the factors, including the modality of land-use, afforested period, tree species, climate factors and soil properties, which may affect the soil C and nutrients. (1) The patterns of land-use affect the accumulation of soil organic matter, thus influence the accumulation of soil C and nutrients; (2) Soil C and N increase with the years of artificial forests, while soil P is on the contrary; (3) The effects of different tree species on soil C and nutrients vary widely; (4) In terms of climate, the C sink of Tibetan plantation soil is most likely to be affected by precipitation, while the nutrient is more likely to be influenced by temperature; (5) Among soil properties, the most related factor to C is soil texture. Furthermore, our review pointed out that future research on soil ecological functions should be focused on soil microbes on Tibet plantation. At the end, we concluded three major challenges for the future research. Therefore, this review contributes to a better understand the effects of plantation on soil C and nutrients on the Tibetan Plateau.