长期氮添加对东北地区兴安落叶松人工林土壤酶的影响

全球氮沉降持续增加导致的氮沉降量上升,已成为森林中物质循环的重要生态因子。为探讨氮沉降增加对东北地区兴安落叶松人工林土壤酶的影响,对长期人工添加无机氮(NH4NO3)和未添加无机氮的兴安落叶松人工林土壤酶活性进行了比较分析。实验分为2个处理,分别为对照处理(CK:0kg·N·hm^-2·a^-1)和无机氮处理(IN:10kg·N·hm^-2·a^-1),每个处理含3个重复。结果表明,在连续8年添加无机氮的情况下,β-1,4-糖苷酶(BG)、酸性磷酸酶(AP)和过氧化物酶(PER)活性上升(5.56%、8.66%和0.61%);纤维素二糖水解酶(CBH)、亮氨酸氨基肽酶(LAP)和多酚氧化酶(POX)活性下降(10.71%、3.85%和12.30%)。与之相对应的土壤碳、氮和磷元素含量也有变化(0.80%、12.66%和-2.25%)。因此,在氮沉降量逐年增加的情况下,研究土壤酶活性变化,能更好的解释森林生态系统物质循环特性,理解生物地球物质循环机理并预测未来土壤碳库变化。

Effects of Long-term Nitrogen Addition on Soil Enzymes in Larix gmelinii Plantation in Northeast China

The increase of nitrogen deposition hadbecame a significant ecological factor effecting the material cycle in forest. We examined the effects of nitrogen deposition on soil enzyme activities in inorganic nitrogen addition and control plots in Larix gmelinii(Rupr.) Rupr. plantation, in northeast China. The experiment was divided into two treatment groups, one was control treatment(CK:0 kg·N·hm^-2·a^-1) and another was inorganic nitrogen treatment(IN:10 kg·N·hm^-2·a^-1). Each treatment included 3 replicate plots. Over 8 years of inorganic nitrogen addition, our results showed that N fertilization increased the activities of β-1, 4-glucosidase(BG), acid phosphatase(AP), and peroxidase(PER)(5.56%, 8.66% and 0.61%)while reduced the activities of cellobiohydrolase(CBH), leucine aminopeptidase(LAP) and phenol oxidases(POX)(10.71%, 3.85% and 12.30%). The long-term inorganic nitrogen addition treatment had a significant effect on soil enzyme activity and soil carbon, nitrogen and phosphorus cycles(0.80%, 12.66% and -2.25%). Therefore, it is important to include the soil enzyme activity when studying the response of biogeochemical cycle and soil carbon dynamics to climate changein forest ecosystems in future research, while nitrogen deposition increases year by year.