基于干、湿筛法下滇中森林土壤团聚体酶活性特征对氮沉降的响应

研究森林土壤团聚体酶活性对氮沉降的响应差异以及团聚体酶活性的影响因素,以滇中亚高山云南松林和华山松林为研究对象,于2020年6月至2021年5月通过野外模拟氮沉降试验,设置对照CK,0 g/(m²·a)N]、低氮LN,10 g/(m²·a)N]、中氮MN,20 g/(m²·a)N]、高氮HN,25 g/(m²·a)N],分别采集旱季(2021年2月)和雨季(2020年8月)的土壤样品,分析土壤团聚体中脲酶(Ure)、蔗糖酶(Inv)和酸性磷酸酶(AP)的变化特征,以及与环境因子的交互作用,阐明不同筛分方式下土壤团聚体酶活性对氮沉降的响应特征。结果表明：(1)氮沉降对2种林分下土壤团聚体的分布未造成显著影响,而不同筛分方式则影响显著;不同氮沉降水平下,土壤团聚体中3种酶活性均表现出LN促进,MN与HN抑制;(2)与干筛法相比,湿筛法下土壤团聚体中酶活性均有显著下降,Inv和Ure的团聚体酶活性的降幅均在20%以上,AP的降幅可达57.55%;(3)土壤干筛、湿筛团聚体酶活性的几何平均数(GMe...

Response of Enzyme Activity Characteristics of Forest Soil Aggregates to Nitrogen Deposition in Central Yunnan Based on Dry and Wet Screening Method

To study the response difference of forest soil aggregate enzyme activity to nitrogen deposition and the influencing factors of aggregate enzyme activity, JP2]taking the alpine P. yunnanensis forest and P. armandiiJP] forest in Central Asia of Yunnan Province as the research object, the field simulated nitrogen deposition test was conducted from June 2020 to May 2021. The settings were: control CK, 0 g/(m²·a)N], low nitrogen LN, 10 g/(m²·a)N], JP2]medium nitrogen MN, 20 g/(m²·a)N] and high nitrogen HN, 25 g/(m²·a)N]. TheJP] soil samples in dry season (February 2021) and rainy season (August 2020) were collected respectively. The variation characteristics of urease(Vre), invertase(Inv) and acid phosphatase(AP) in soil aggregates and their interaction with environmental factors were analyzed to clarify the response characteristics of soil aggregate enzyme activity to nitrogen deposition under different screening methods. The results showed that: (1) Nitrogen deposition had no significant effect on the distribution of soil aggregates under the two stands, but different screening methods had significant effects; The activities of three enzymes in soil aggregates were promoted by LN and inhibited by MN and HN under different nitrogen deposition levels; (2) Compared with the dry sieving method, the enzyme activity in soil aggregates decreased significantly under the wet sieving method. The decline of enzyme activity in Inv and Ure aggregates was more than 20%, and the decline of AP was the highest, up to 57.55%; (3) The geometric mean GMea of soil dry sieve and wet sieve aggregate enzyme activity was higher than that of mixed soil, and the GMea under dry sieve condition was the highest, with an average increase of 50.35% compared with that under wet sieve condition. The stand among different factors had the greatest impact on Inv, while season had the greatest impact on Ure and AP. In conclusion, soil aggregates can isolate and protect soil enzyme activity. At the same time, the protection effect is jointly affected by season, stand type, screening method, and nitrogen application level. The research results provide a theoretical basis for the soil ecological process of regional forest ecosystem under nitrogen deposition and maintaining the stability of soil ecosystem.