School of Geographical Sciences, Fujian Normal University, Fuzhou 350117, China.
Key Laboratory for Humid Subtropical Eco-Geographical Processes of Ministry of Education, Fujian Normal University, Fuzhou 350117, China.
Ying Yong Sheng Tai Xue Bao. 2024 Aug;35(8):2091-2098. doi: 10.13287/j.1001-9332.202408.007.
Soil stoichiometric ratios serve as valuable indicators for the composition and quality of soil organic matter. While available studies predominantly examine the soil stoichiometric ratios of carbon (C), nitrogen (N), and phosphorus (P), limited attention has been paid on the influence of forest restoration on soil stoichiometric ratios of potassium (K), calcium (Ca), and magnesium (Mg). We analyzed soil K, Ca, and Mg content, as well as elemental stoichiometric ratios, in secondary forests with varying restoration periods (5, 8, 21, 27 and 40 years) and a natural forest, in order to examine the impact of forest restoration on soil stoichiometry. The results showed that soil C and N contents decreased significantly with increasing soil layers. Soil stoichiometric ratios decreased significantly with increasing soil layers except for K:P, Mg:P, and P:Ca. With the increases of forest restoration years, soil C and N contents significantly increased in 0-10 cm soil layer, Ca content in 10-20 cm soil layer significantly increased, and total P content in 20-40 cm layer significantly decreased. However, soil K and Mg contents in each soil layer did not differ among five restoration ages. With the increases of restoration years, C:Ca, N:Ca and P:Ca in 0-10 cm soil layer significantly increased, and C:P, N:P, and K:P in 20-40 cm soil layer significantly increased, while P:Ca in 20-40 cm soil layer significantly decreased. In all soil layers, K:P and Mg:P were significantly and negatively correlated with soil total P content, and C:Ca and N:Ca were significantly and positively correlated with soil mineral N, available P, and available K content. With the increases of the restoration ages of secondary forests, soils are gradually P-limited and progressively restricted by Ca element in the later years, leading to the limitation of multiple nutrients.
土壤化学计量比率可作为土壤有机质组成和质量的有价值指标。虽然现有研究主要考察了碳（C）、氮（N）和磷（P）的土壤化学计量比，但对森林恢复对钾（K）、钙（Ca）和镁（Mg）土壤化学计量比的影响关注较少。我们分析了不同恢复年限（5、8、21、27 和 40 年）的次生林和天然林的土壤 K、Ca 和 Mg 含量以及元素化学计量比，以检验森林恢复对土壤化学计量学的影响。结果表明，土壤 C 和 N 含量随土层深度的增加而显著降低。除 K:P、Mg:P 和 P:Ca 外，土壤化学计量比随土层深度的增加而显著降低。随着森林恢复年限的增加，0-10cm 土层土壤 C 和 N 含量显著增加，10-20cm 土层 Ca 含量显著增加，20-40cm 土层总 P 含量显著降低。然而，各土层土壤 K 和 Mg 含量在五个恢复年龄之间没有差异。随着恢复年限的增加，0-10cm 土层 C:Ca、N:Ca 和 P:Ca 显著增加，20-40cm 土层 C:P、N:P 和 K:P 显著增加，而 20-40cm 土层 P:Ca 显著降低。在所有土层中，K:P 和 Mg:P 与土壤总 P 含量呈显著负相关，C:Ca 和 N:Ca 与土壤矿质 N、有效 P 和有效 K 含量呈显著正相关。随着次生林恢复年龄的增加，土壤逐渐受到 P 的限制，在后期受到 Ca 元素的限制，导致多种养分的限制。
