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以鼎湖山不同演替阶段的3种森林类型(马尾松针叶林、针阔叶混交林和季风常绿阔叶林)为研究对象,2009年6月开始,在森林里喷施不同处理水平的模拟酸雨(对照(p H 4.5的天然湖水)、T1(p H 4.0)、T2(p H 3.5)和T3(p H 3.0)),2012年4月—2013年3月对模拟酸雨下土壤呼吸速率及其相关影响因子进行观测,试图揭示南亚热带不同演替阶段森林土壤呼吸对酸雨的响应规律及机制。结果表明:模拟酸雨抑制了森林土壤呼吸,但抑制作用随森林演替阶段、观测季节和处理水平的不同而不同;模拟酸雨没有显著影响松林的土壤呼吸,但却显著地抑制了阔叶林土壤呼吸(P<0.05),同时在一定程度上抑制了混交林土壤呼吸(P=0.10);与对照相比,阔叶林T1、T2和T3处理的年平均土壤呼吸速率分别下降了0.1%、10.5%和17.1%,混交林为-1.7%、8.1%和13.9%,而松林则为1.1%、1.9%和8.1%;3个林型土壤呼吸对模拟酸雨的响应敏感性随森林的顺行演替而增强。但模拟酸雨对土壤呼吸的抑制作用具有季节差异性,抑制作用只在湿季达到显著差异,且只有强酸处理T3显著抑制了土壤呼吸。模拟酸雨对土壤呼吸的抑制作用与其胁迫下土壤酸化而导致土壤微生物活性下降有关,这种下降程度也大体上随森林的顺行演替而增强。
Three forest types (Pinus massoniana coniferous forest, coniferous broadleaved mixed forest and monsoon evergreen broad-leaved forest) in different succession stages of Dinghushan were studied. Beginning in June 2009, different treatment levels were sprayed in the forest Simulated acid rain (control (natural lake of p 4.5), T1 (p H 4.0), T2 (p H 3.5) and T3 (p H 3. 0), April 2012-March 2013 simulated soil respiration under simulated acid rain Rate and its related impact factors in order to reveal the law and mechanism of the response of forest soil respiration to acid rain at different successional stages in South Asia. The results showed that simulated acid rain inhibited soil respiration in forest, but the inhibition varied with forest succession stage, observation season and treatment level. Simulated acid rain did not significantly affect the soil respiration of pine forest, but significantly inhibited the growth of broad-leaved forest soil (P <0.05), and inhibited soil respiration in mixed forest to a certain extent (P = 0.10). Compared with the control, annual average soil respiration rates of T1, T2 and T3 in deciduous forests decreased by 0.1% 10.5% and 17.1% respectively. The mixed forest was -1.7%, 8.1% and 13.9%, while the pine forest was 1.1%, 1.9% and 8.1% respectively. The sensitivity of soil respiration to simulated acid rain Successive and enhanced. However, the simulated acid rain had a seasonal difference in soil respiration inhibition, and the inhibition only reached a significant difference in the wet season, and T3 treatment significantly inhibited soil respiration. The inhibitory effect of simulated acid rain on soil respiration was related to the decrease of soil microbial activity caused by soil acidification under the stress of acid rain. The degree of decline was also generally enhanced with the succession of forests.