神农架4种典型针叶人工林土壤酶活性及其生态化学计量特征

Soil Enzyme Activity and Its Ecological Stoichiometry in Four Typical Coniferous Planted Forests in Shennongjia National Nature Reserve, China

[目的]探讨土壤酶活性及其生态化学计量比对土壤微生物养分的限制和土壤养分有效性的指示作用。[方法]以神农架地区水杉、柳杉、落叶松和华山松4种人工林纯林土壤为研究对象,测定不同林分土壤酶活性及其生态化学计量比和土壤化学性质。[结果]柳杉林、华山松林和落叶松林土壤β-葡萄糖苷酶(BG)活性显著高于水杉林,落叶松林土壤β-乙酰葡糖胺糖苷酶(NAG)活性显著高于其他3个林分,不同林分间土壤磷酸单酯酶(AP)差异不显著;水杉林土壤BG:NAG和BG:AP显著低于其他3个林分,落叶松林土壤BG:NAG显著低于柳杉林和华山松林,落叶松林土壤NAG:AP显著高于其他3个林分,其中,本区域4种林分土壤NAG:AP(1.01±0.22)指示4种类型人工林土壤微生物可能受到土壤氮限制。冗余分析显示:土壤有机碳和pH值是土壤酶活性的重要影响因素。[结论]林分是土壤酶活性及其生态化学计量比的重要影响因素,其对土壤有机碳和pH值的影响是调控土壤酶活性变化的主要因素。

[Object] To study the role of soil enzyme activity and its ecological stoichiometry in limiting soil microbial nutrients and indicating soil nutrient availability. [Method] Soil enzyme activity and its ecological stoichiometry, along with soil physical and chemical properties, were measured in Metasequoia glyptostroboides, Cryptomeria japonica var. sinensis, Larix gmelinii and Pinus armandii forests in Shennongjia National Nature Reserve.[Result] The soil β-glucosidase(BG) activity in C. japonica, P. armandii and L. gmelinii forests was significantly higher than that in M. glyptostroboides forest. The soil β-acetylglucosidase(NAG) activity in L. gmelinii forest was significantly higher than that in other forests. There was no significant difference in soil acid phosphatase(AP) activity among the four types of forest stands. Soil BG:NAG and BG:AP in M. glyptostroboides forest were significantly lower than that in other forests. Soil BG:NAG in L. gmelinii forest was also significantly lower than that in C. japonica and P. armandii forests. Soil NAG:AP in L. gmelinii forest was significantly higher than that in other forests. Soil NAG:AP(1.01±0.22) in the region indicated the soil microbes were limited by soil nitrogen. Redundancy analysis showed that soil organic carbon and pH value were important factors influencing soil enzyme activity. [Conclusion] Forest stand is an important factor influencing soil enzyme activity and the ecological stoichiometry of soil enzyme. The effect on soil organic C and pH is the key factor regulating soil enzyme activity.