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土壤酶参与土壤碳氮转化,同时土壤碳氮状况又是土壤酶活性的基础,而大气氮沉降通过影响土壤酶活性进而影响土壤CO_2释放.通过野外模拟试验,探讨不同氮沉降量对马尾松土壤呼吸和酶活性的影响,探索该区域马尾松土壤呼吸(Rs)与土壤温度(T)、土壤湿度(W)、Ure(脲酶)、Ive(转化酶)、CAT(过氧化氢酶)及ACP(酸性磷酸酶)的关系,为深入研究氮沉降对马尾松林森林生态系统的影响提供参考.2014年5月~2015年7月在缙云山马尾松林设置3个氮添加水平和一个无氮添加的对照处理:低氮[N_5,20 g·(m~2·a)~(-1)],中氮[N_(10),40 g·(m~2·a)~(-1)]、高氮[N_(15),60 g·(m~2·a)~(-1)]和对照[N0,0g·(m~2·a)~(-1)],每个处理量分4次,在每个季度开始各施1次,每个处理各9次重复,采用ACE(automated soil CO_2exchange station,UK)自动土壤呼吸监测系统分别对土壤呼吸、土壤温度和土壤湿度进行分析测定.结果表明:1土壤酶和土壤呼吸均具有明显的季节变化规律,各处理土壤呼吸均表现为夏季最高,其次是春季和秋季,最低为冬季,而各处理土壤酶活性则无一致的变化规律.2总体而言,氮沉降对土壤呼吸和酶活性均有抑制作用,且抑制程度随氮浓度增加而加强,但冬季氮沉降对马尾松林土壤呼吸有促进作用,春、夏、秋这3个季节氮沉降对Ure、Ive、CAT及ACP有抑制作用,而冬季氮沉降对4种土壤酶活性影响则存在差异.3逐步回归表明,无氮和低氮处理时,T、Ure和Ive对Rs的贡献较大,且随着T、Ure和Ive的增加,Rs也急剧增加;中氮处理时,T、Ure和CAT对Rs的贡献较大,Rs随着T、Ure和Ive的增加而增加;高氮处理时,Rs随着Ure的增加而降低,随着CAT和W的增加而增加.
Soil enzymes involved in soil carbon and nitrogen transformation, while soil carbon and nitrogen conditions is the basis of soil enzyme activity, and atmospheric nitrogen deposition by affecting soil enzyme activity and thus affect soil CO 2 release.Through the field simulation test to explore different nitrogen deposition on Pinus massoniana soil Respiration and enzyme activity of Pinus massoniana to explore the effects of soil respiration (Rs) and soil temperature (T), soil moisture (W), Ure (urease), Ive (conversion enzyme), CAT (catalase) (Acid phosphatase) in the Pinus massoniana forest to provide reference for further study on the effect of nitrogen deposition on the Pinus massoniana forest ecosystem.Monon-pine masson pine forests in Jinyun Mountain from May 2014 to July 2015 were set up with three nitrogen addition levels and one nitrogen-free control The treatments of low N [5,20 g · (m -2 · a -1)], medium N [10, 40 g · m -2 · a -1] Nitrogen [N 15, 60 g · m -2 · a -1] and control [N 0,0 g · (m -2 · a -1)], each treatment volume was divided into 4 The soil respiration, soil temperature and soil moisture were analyzed and measured respectively by automatic soil respiration monitoring system of ACE (automated soil CO_2exchange station, UK) .Results Indicate: 1 soil enzymes and Soil respiration had obvious seasonal variation. Soil respiration in all treatments showed the highest in summer, the next was in spring and autumn, the lowest was in winter, while the activity of soil enzymes in different treatments did not change uniformly.2 Overall, nitrogen deposition Soil respiration and enzyme activities were inhibited, and the degree of inhibition was enhanced with the increase of nitrogen concentration. However, winter nitrogen deposition had a positive effect on soil respiration in Pinus massoniana forest. Nitrogen deposition in spring, summer and autumn was positively correlated with Ure, Ive, CAT and ACP, while winter nitrogen deposition had different effects on four soil enzyme activities.3 The stepwise regression showed that T, Ure and Ive contributed more to Rs than N and N treatments, T, Ure and Ive, and Rs also increased sharply. During medium N treatment, T, Ure and CAT contributed more to Rs, while Rs increased with the increase of T, Ure and Ive. During high N treatment, The Ure increases and decreases, with the increase of CAT and W increases.