米槠叶凋落物分解及养分释放对模拟N沉降的响应  

Responses of leaf litter decomposition and nutrient release to simulated nitrogen deposition of Castanopsis carlesii

作　　者：王家骏[1,2] 程煜[1,2] 杨玉盛[1,2] 林成芳[1,2] 林伟盛[1,2] 彭建勤 

机构地区：[1]湿润亚热带山地生态国家重点实验室培育基地,福建福州350007 [2]福建师范大学地理科学学院,福建福州350007

出　　处：《福建林学院学报》2014年第2期113-119,共7页Journal of Fujian College of Forestry

基　　金：国家自然科学基金项目(31000298;31270584);福建省自然科学基金项目(2009J05055);福建师范大学优秀青年骨干教师培养基金项目(fjsdjk2012075)

摘　　要：通过原位分解研究三明格氏栲保护区内米槠叶凋落物的分解及其对模拟N沉降的响应。结果表明:高氮(HN)、中氮(MN)、低氮(LN)和对照(CK)4种处理的米槠叶凋落物的分解都呈先快后慢的变化趋势,分解速率为CK>MN>LN>HN,添加N对米槠叶凋落物的分解起到了抑制作用。在监测期(720 d)内,MN处理(10 g·m-2·a-1)对分解速率影响较小,N含量太高(15 g·m-2·a-1),负作用增强,高于10 g·m-2·a-1的N沉降会显著抑制木质素的分解释放(P<0.05)。对纤维素分解的抑制作用仅在部分时间里部分的N沉降量作用显著(P<0.05)。分解360 d后,添加N即在一定程度上影响了全C和全N的分解释放,且添加15 g·m-2·a-1N时,负面影响更明显。全P均呈淋溶—富集—释放模式变化,270-720 d,添加N显著抑制全P的分解释放(P<0.05)。K的分解释放规律与全C的较相似,均随时间的延长逐渐减少,且在第360天的分解速率明显快于第720天,添加N特别是LN处理(5 g·m-2·a-1)在0-540 d会显著提高K的残留(P<0.05)。这可能是N沉降使中亚热带常绿阔叶林土壤—凋落物系统内可得性N增加,改变了原有的养分平衡,抑制了微生物的活动,从而降低了分解酶的活性而影响米槠叶凋落物的分解。A field simulated experiment was conducted in Castanopsis carlesii forest in Sanming C.kawakamii Nature Reserve, to study the responses of C.carlesii leaf litter decomposition and nutrients release to increased N deposition .The treatments were designed as CK（0 g· m-2· a-1）, LN（5 g· m-2· a-1）, MN（10 g· m^-2· a^-1） and HN（15 g· m^-2· a^-1）, adding N could inhibit those leaf litter′s decompositions , the speeds were CK ＆gt;MN＆gt;LN＆gt;HN and slow down after 1 a.In the monitoring period （720 d） , LN and HN could significantly inhibited decomposition （P〈0.05）.More than 10 g· m^-2· a^-1 of N deposition could significantly inhibited leaf litter lignin′s decomposition （P〈0.05） but not so obviously to cellulose.After 360 d, N deposition could affected its C and N decomposition , and the negative impact of HN was more obvious .The release pattern of P was leaching-enriched-releasing , and in 270-720 d adding N could significantly inhibit their P releasing （P〈0.05）.The releasing disciplines of K were similar to C and in 0-540 d adding N, especially LN would significantly inhibited K releasing （P〈0.05）.This may be so that N deposition increased the N availability in subtropical evergreen broad-leaf forest, which changed the original nutrients balance , so that inhibited the activity of microbial , thereby reducing the activity of enzyme and then affected the C.carlesii litter′s decomposition .

关 键 词：N沉降 米槠 叶凋落物 分解 养分释放 

分 类 号：S718.55[农业科学—林学]