【摘要】 探讨农田转化林地对土壤可溶性氮的初期影响，及其在不同造林树种和土层中的差异，为城市森林营造中的树种选择提供基础数据。以邻近传统水稻田为对照，分析农田转化林地7 a后，水杉(Metasequoia glyptostroboides)、香樟(Cinnamomum camphora)和重阳木(Bischofia polycarpa)纯林林地0<h≤60 cm土壤可溶性氮质量分数及其垂直分布特征。结果表明：(1)农田转化林地短期内显著降低了0<h≤60 cm土层土壤可溶性氮各组分的质量分数，可溶性氮各组分的质量分数降幅由大到小的顺序为：硝态氮(-64.89%)、可溶性全氮(-29.73%)、可溶性有机氮(-26.11%)、铵态氮(-15.12%);(2)可溶性氮在各纯林土壤中的降幅由大到小的顺序为：香樟林地、水杉林地、重阳木林地；(3)0<h≤40 cm土层土壤可溶性全氮、可溶性有机氮、硝态氮和铵态氮的损失量分别占0<h≤60 cm土壤总损失量的89.91%、94.59%、82.86%和75.85%;(4)试验地可溶性氮各组分与土壤含水率、有机碳、全氮和微生物生物量碳氮呈显著或极显著正相关(P<0.01),与土壤密度呈极显著负相关(P<0.01)。农田转化林地短期内降低了土壤可溶性氮各组分的质量分数，表明林地对农田土壤氮流失具有一定的缓冲作用。更多还原

【Abstract】 The study aimed to evaluate the short-term effect of converting cropland to plantation on soil soluble nitrogen and its characteristics varied with different tree species and soil depths for acquiring some basis data, which would be benefited for construction and management of urban forestry. The contents and distributions of total soluble nitrogen（TSN）, soluble organic nitrogen（SON）, nitrate（NO^-₃-N） and ammonium（NH⁺₄-N） in soil layers at a depth of 0<h≤60 cm were analyzed under three pure plantations（Metasequoia glyptostroboides, Cinnamomum camphora and Bischofia polycarpa） and the adjacent control cropland in alluvial plain of eastern China. The converting cropland to plantation significantly decreased the contents of TSN, SON, NO^-₃-N and NH⁺₄-N in 0<h≤60 cm soil, and these content decreases of TSN, SON, NO^-₃-N and NH⁺₄-N were in the descending order of NO₃-N（-64.89%）, TSN（-29.73%）, SON（-26.11%） and NH⁺₄-N（-15.12%）. The decrease of soluble nitrogen content in 0<h≤60 cm soil varied with monoculture stands in the descending order of C. camphora, M. glyptostroboides and B. polycarpa. The content decreases of TSN, SON, NO^-₃-N and NH⁺₄-N in 0<h≤40 cm soil layer accounted for 89.91%, 94.59%, 82.86% and 75.85% of those in 0<h≤60 cm soil layer. The soluble nitrogen was significantly positively correlated with soil water content, organic carbon, total nitrogen, microbial biomass carbon and nitrogen, and was significantly negatively correlated with soil bulk density. Converting cropland to plantation decreased the contents of soluble nitrogen fractions in the short-term, indicating that the forest-belt near farmland maybe have buffer effect of agricultural soil nitrogen loss.更多还原