Consistent profile pattern and spatial variation of soil C/N/P stoichiometric ratios in the subalpine forests
Consistent profile pattern and spatial variation of soil C/N/P stoichiometric ratios in the subalpine forests
复制标题
亚高山森林土壤C/N/P化学计量比的一致剖面格局和空间变化
DOI：
10.1007/s11368-017-1665-9
复制
发表时间：
2017-08-01
影响因子：
3.6
通讯作者：
Pang, Xueyong
中科院分区：
文献类型：
--
作者：
Feng, Defeng;Bao, Weikai;Pang, Xueyong
目的土壤碳(C)、氮(N)和磷(P)化学计量学的垂直格局仍然存在争议，其控制因素在整个土壤剖面中的相对贡献也很少被理解。本研究旨在研究青藏高原东部亚高山森林土壤C/N、N/P、C/P比值的垂直变化及其影响因素。材料与方法采集132个森林样点的0~10、10~20、20~30、30~50、50~100 cm土样，分析土壤C/N、N/P、C/P比值的垂直分布特征。通过对11个相关环境因子(海拔、纬度、经度、土壤pH、土壤容重、相对石块含量、土层顺序、坡度、位置、森林类型和优势树种)的测量，利用Boosted回归树(BRT)分析方法研究了它们对各土层化学计量比的相对贡献。BRT模型较准确地预测了土壤C/N、N/P和C/P比值(R2=0.49~0.97%)。对于土壤C/N和N/P比，海拔与纬度的关系在五个土层中的贡献最大，而土壤pH和容重在靠近地表的土层中贡献最大。土壤容重和海拔是影响0-30和30-100 cm土层C/P比的最重要因素。结论青藏高原森林土壤C/N/P化学计量比及其控制因素的相对重要性在土壤剖面内发生了变化。还需要进一步的研究，以了解土壤化学计量学和生物地球化学对整个土壤剖面环境变化的调节机制。
PurposeThe vertical patterns of soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry are still controversial, and relative contribution of their controlling factors also is rarely understood for the whole soil profile. This study aimed to assess the vertical variation of both C/N, N/P, C/P ratios and their determining factors along soil profiles in subalpine forests of the eastern Tibetan Plateau.Materials and methodsSoil samples at five depths (0–10, 10–20, 20–30, 30–50, and 50–100 cm) were collected from 132 forest sites to evaluate the vertical distribution of soil C/N, N/P, and C/P ratios. Eleven relevant environmental factors (e.g., altitude, latitude, longitude, soil pH, soil bulk density, relative stone contents, soil order, slope, position, forest type, and dominant tree species) were measured to examine their relative contribution on stoichiometric ratios within each soil layer using boosted regression tree (BRT) analysis.Results and discussionSoil C/N, N/P, and C/P ratios consistently decreased with increasing soil depth. BRT models accurately predicted the soil C/N, N/P, and C/P ratios in the upper four layers (R2= 49–97 %). For soil C/N and N/P ratios, altitude associated with latitude had the highest contribution across five soil layers, while the contributions of soil pH and bulk density were significant within soil layers closer to the surface. Independently, soil bulk density and altitude were the most important factors of C/P ratios in 0–30- and 30–100-cm soil layers.ConclusionsThis study indicated that soil C/N/P stoichiometric ratios, and the relative importance of their controlling factors, shifted within soil profiles across Tibetan Plateau forests. Further research will be needed to understand the regulatory mechanism of soil stoichiometry and biogeochemistry in response to environmental change at whole soil profiles.