红松人工林土壤酶活性与化学性质对氮添加的响应

土壤酶参与土壤中进行的众多复杂的生物化学过程，对陆地生态系统物质循环具有重要作用.为了探索温带森林土壤酶活性和化学性质对氮沉降的响应，本研究依托于黑龙江凉水国家级自然保护区的红松（Pinus koraiensis）人工林氮添加实验样地，分析了4种土壤酶活性.结果表明，土壤中N-乙酰-氨基葡萄糖苷酶（NAG）和碱性磷酸酶（AKP）活性均随着施氮浓度增加显著升高，而β-葡糖苷酶（BG）以及酸性磷酸酶（ACP）活性在不同的施氮处理之间无显著差异；同一施氮水平下的上层（0~10 cm）土壤的全碳、全氮、全磷、有效氮含量以及4种酶活性显著高于下层（10~20 cm）土壤，pH值则无显著差异.全碳与NAG、BG、AKP、ACP之间均存在极显著正相关，全氮与BG、NAG、AKP、ACP存在显著或极显著正相关，有效氮与NAG、AKP间存在显著和极显著正相关，全磷与ACP、AKP存在显著和极显著正相关.施氮水平和土层对土壤酶活性及土壤化学性质存在不同程度的影响，氮的长期大量输入可直接或间接地改变土壤化学性质并影响土壤酶活性.

Response of Soil Enzyme Activity and Chemical Properties to Nitrogen Addition in a Korean Pine Plantation

Soil enzymes participate in numerous complex biochemical processes that take place in the soil and play an important role in the material circulation of terrestrial ecosystems. To explore the response of soil enzyme activities and chemical properties to nitrogen deposition in temperate forests, this study analyzed four soil enzyme activities based on the nitrogen addition experiment plot of Korean pine (Pinus koraiensis) plantation, which was located in the Liangshui National Natural Reserve, Heilongjiang Province. The results showed that the activities of N-acetyl-glucosidase (NAG) and alkaline phosphatase (AKP) increased significantly with increasing nitrogen application concentration. The activity of beta-glucosidase (BG) and acid phosphatase (ACP) was not significantly different among different nitrogen application treatments. The contents of total carbon, total nitrogen, total phosphorus, and available nitrogen and four enzyme activity in the upper soil (0-10 cm) under the same nitrogen application level were significantly higher than those in the lower soil (10-20 cm), but the pH values were not significantly different. Total carbon has an extremely significant positive correlation with NAG, BG, AKP, and ACP. Total nitrogen has an obvious or extremely significant positive correlation with BG, NAG, and AKP as well as ACP. The available nitrogen has an obvious and highly significant positive correlation with NAG and AKP. The total phosphorus has an obvious and extremely significant positive correlation with ACP and AKP, respectively. The nitrogen application level and the soil layer had different effects on soil enzyme activity and soil chemical properties. Long-term large input of nitrogen can directly or indirectly change soil chemical properties and affect soil enzyme activity.