不同类型城市森林对土壤肥力的影响

以东北林业大学城市林业示范研究基地中9种人工林(兴安落叶松林、樟子松林、黑皮油松林、黄波罗林、胡桃楸林、水曲柳林、白桦林、蒙古栎林、针阔混交林)及附近的农耕地和撂荒地土壤为研究对象，通过对林地土壤不同层次pH值、有机质及主要养分含量的测定分析，研究了不同林型对土壤肥力的影响.结果表明：阔叶林(除蒙古栎林)的土壤趋于中性，针阔混交林、兴安落叶松林、樟子松林和黑皮油松林的土壤呈微酸性，蒙古栎林的土壤呈酸性；随土壤深度增加，土壤有机质、水解氮、速效钾、有效磷、全氮、全磷含量均呈下降趋势.不同林地土壤同一层次化学指标整体差异显著(P＜0.05).土壤肥力优劣为：水曲柳林>黄波罗林>针阔混交林>胡桃楸林>白桦林>撂荒地>农耕地>樟子松林>兴安落叶松林>蒙古栎林>黑皮油松林，说明阔叶林(除蒙古栎林)和针阔混交林中的土壤肥力增加，而针叶林的土壤肥力趋于下降.

Effects of different type urban forest plantations on soil fertility

Aimed to study the effects of different urban forest plantations on soil fertility, soil samples were collected from eight mono-cuhured plantations (Larix gmelinii, Pinus sylvestris var. mongolica, Pinus tabulaeformis var. mukdensis, Phellodendron amurense, Juglans mandshurica, Fraxinus mandshurica, Betula platyphylla, and Quercus mongolica ) and one mixed plantation (P. sylvestris var. mongolica + F. mandshurica + Picea koraiensis + P. amurerue + B. platyphylla )established in Northeast Forestry University's Urban Forestry Demonstration Research Base in the 1950s, with two sites of neighboring farmland and abandoned farmland as the control. The soils in broadleaved forest plantations except Q. mongolica were near neutral, those in mixed plantation, L.gmelinii, P. sylvestris var. mongolica, and P. tabulaeformis var. mukdensis were slightly acidic,and that in Q. mongolica was acidic. The contents of soil organic matter, total N and P, available P and K, and hydrolysable N tended to decrease with soil depth. There existed significant differences in the chemical indices of the same soil layers among different plantations. The soil fertility was decreased in the order of F. mandshurica ＞ P. amurense ＞ mixed plantation ＞J. mandshurica ＞ B. platyphylla ＞ abandoned farmland ＞ farmland ＞ P. sylvestris var. mongolica ＞ L.gmelinii ＞ Q. mongolica ＞ P. tabulaeformis var. mukdensis, suggesting that the soil fertility in broadleaved forest plantations except Q. mongolica and in mixed plantation increased, while that in needle-leaved forest plantations tended to decrease.