凋落物和林下植被对杉木林土壤碳氮水解酶活性的影响机制  

Mechanism of litter and understory vegetation effects on soil carbon and nitrogen hydrolase activities in Chinese fir forests

作　　者：杨洋[1,2] 王继富[1] 张心昱[2] 李丹丹[2,3] 王辉民[2] 陈伏生[4] 孙晓敏[2] 温学发[2] 

机构地区：[1]哈尔滨师范大学地理科学学院,哈尔滨150025 [2]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [3]沈阳农业大学生物科学技术学院,沈阳110866 [4]江西农业大学江西省竹子种质资源与利用重点实验室,南昌330045

出　　处：《生态学报》2016年第24期8102-8110,共9页Acta Ecologica Sinica

基　　金：国家重点基础研究发展计划资助项目(2012CB416903);国家自然科学基金资助项目(31130009;31290222;41571251;41071332)

摘　　要：凋落物和林下植被在森林生态系统土壤碳、氮循环过程中发挥重要作用,目前关于亚热带杉木人工林凋落物和林下植被对土壤碳氮水解酶活性影响机制还不清楚。在亚热带杉木人工林设立去除凋落物+去除林下植被(LR+UR)、去除凋落物+保留林下植被(LR+U)、凋落物加倍+保留林下植被(LD+U)、凋落物加倍+割倒林下植被归还(LD+UC)处理。通过研究各处理对土壤环境因子(土壤温度(ST)、土壤含水量(SWC)、土壤酸度(p H)、硝态氮(NO_3^--N)、氨态氮(NH_4^+-N)、溶解性有机碳(DOC))和土壤碳氮水解酶(β-1,4-葡萄糖苷酶(βG)和β-1,4-N-乙酰葡糖氨糖苷酶(NAG))活性的影响,揭示凋落物和林下植被对杉木林土壤碳氮水解酶活性影响机制。结果表明:(1)通过比较LR+U和LD+U处理发现,短期内添加凋落物有增加土壤p H、NH+4-N含量和提高βG、NAG活性的趋势,但未达到显著水平(P>0.05);(2)LR+UR与LR+U处理间的比较发现,去除林下植被有降低SWC、p H、NH+4-N含量、NAG活性的趋势,并显著降低了土壤DOC含量和βG活性(P<0.05);(3)将LR+UR分别与LD+U、LD+UC处理进行比较表明,添加凋落物同时保留林下植被显著增加了SWC、p H、DOC和NH+4-N含量,并增强了βG和NAG活性(P<0.05),而且林下植被割倒归还比林下植被正常生长更有利于土壤βG、NAG活性的提高和SWC、DOC含量的增加,但是对ST和NO-3-N含量没有显著影响(P>0.05);(4)土壤水解酶活性与SWC、DOC表现为极显著正相关关系(P<0.01)。总之,凋落物和林下植被影响碳氮水解酶活性的机制,主要是通过调节SWC、增加DOC含量,影响βG、NAG活性;βG、NAG活性增强也会加快土壤有机质(SOM)分解,增加土壤DOC含量。Litter and understory vegetation play important roles in soil carbon and nitrogen cycles in forest ecosystems. However, the mechanism of the effects of litter and understory vegetation on soil carbon and nitrogen hydrolase activities remains unclear in subtropical Chinese fir forests. In this study, four different litter and understory treatments （litter and understory vegetation removal （ LR ＋ UR）, litter removed but understory vegetation intact （ LR ＋ U ）, litter doubled and understory vegetation intact （LD ＋U）, litter doubled and understory vegetation clipped but left in situ （LD ＋UC ）） were established in subtropical Chinese fir plantations. We studied the effects of litter and understory vegetation on soil environmental factors （soil temperature （ST）, soil moisture （SWC）, soil acidity （pH）, soil nitrate nitrogen （NO3-N）, ammonia nitrogen （NH4-N） , and dissolved organic carbon （DOC）） and soil carbon and nitrogen hydrolases （β-1, 4- glucosidase （βG） and β-1, 4-N-acetyl-glucosaminidase （NAG）） activities in order to reveal the mechanism of the effects of litter and understory vegetation on soil carbon and nitrogen hydrolase activities. The results showed that： （1） litter addition increased soil pH, NH4-N content, and hydrolase activities compared to the LR＋U and LD＋U treatments, although t the effects were not significant （P 〉 0.05）. （2） A comparison of the LR＋UR and LR＋U treatments showed that understory clipping significantly decreased the DOC content and βG activity （ P 〈 0.05） and tended to reduce SWC, pH, NH4-N, and NAG activity. （3） Litter addition with intact understory significantly increased SWC, pH, DOC, and NH β-N content, and enhanced βG and NAG activities （P 〈 0.05 ）. The understory clipping in situ treatment was even more effective at increasing βG activity, NAG activity, SWC, and DOC than the understory unclipped treatment. However, neither LD＋U nor LD＋UC treatment had a signific

关 键 词：凋落物 林下植被 杉木林 土壤环境因子 β-1 4-葡萄糖苷酶 β-1 4-N-乙酰葡糖氨糖苷酶 

分 类 号：S714[农业科学—林学]