模拟氮沉降及经营方式对毛竹林土壤酶活性的影响

研究粗放经营和集约经营条件下毛竹林蔗糖酶、纤维素酶、硝酸还原酶、脲酶和过氧化氢酶5种土壤酶活性对4种氮沉降水平(0、30、60和90 kg·hm^-2·a^-1)的响应.结果表明:与粗放经营相比,集约经营分别显著提高土壤蔗糖酶、纤维素酶和脲酶活性55.5%、112.9%和28.6%,显著抑制硝酸还原酶活性31.5%,对过氧化氢酶活性的影响不显著.氮沉降显著抑制粗放和集约经营方式下毛竹林蔗糖酶活性20.0%～49.4%和36.2%～45.1%、纤维素酶活性20.5%～46.3%和18.3%～49.0%、硝酸还原酶活性67.9%～85.2%和15.2%～34.2%,以及集约经营毛竹林脲酶活性23.1%～47.6%,显著增加了粗放经营毛竹林土壤脲酶活性8.1%～50.6%,对过氧化氢酶活性的影响不显著.氮沉降与经营方式的复合作用除对过氧化氢酶活性的影响不显著外,对其他4种土壤酶活性的影响均达到显著水平.

Effects of simulated nitrogen deposition and management type on soil enzyme activities in Moso bamboo forest.

In this study, a field experiment was conducted using simulated N deposition method in conventionally managed (CM) and intensively managed (IM) Moso bamboo forests to test the responses of five soil enzymes (including β-fructofuranosidase, cellulase, nitrate reductase, hydrogen peroxidase and urease) to simulated N deposition of four treatment levels of 0, 30, 60 and 90 kg N·hm^-2·a^-1. The results showed that compared with CM, IM significantly increased soil β-fructofuranosidase, cellulase, urease activities by 55.5%, 112.9% and 28.6%, respectively, but significantly decreased nitrate reductase activity by 31.5%, and had no significant effect on hydrogen peroxidase activity. Nitrogen deposition significantly decreased soil β-fructofuranosidase (20.0%-49.4% and 36.2%-45.1%), cellulase (20.5%-46.3% and 18.3%-49.0%), nitrate reductase (67.9%-85.2% and 15.2%-34.2%) activities in both CM and IM plots, respectively, and also urease activity (23.1%-47.6%) in IM, but enhanced the urease activity (8.1%-50.6%) in CM, and had no significant effects on hydrogen peroxidase activity. The combination of N deposition and management types significantly impacted the four soil enzyme activities except for hydrogen peroxidase.