塔里木沙漠公路防护林地表凋落物分解对施肥的响应  

Effects of fertilizer addition on surface litter decomposition in the Tarim Desert Highway shelterbelt

作　　者：张雪梅[1,2,3,4] 王永东[1,4] 徐新文[1,4] 雷加强[1,4] 孙景鑫[1,3,4] ZHANG Xuemei WANG Yongdong XU Xinwen LEI Jiaqiang SUN Jingxin(Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 83001 l, China College of Resources and Emdronmental Science, Xinjiang University, Urumqi 830046, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Urumqi 830011, China)

机构地区：[1]中国科学院新疆生态与地理研究所,乌鲁木齐830011 [2]新疆大学资源与环境科学学院,乌鲁木齐830046 [3]中国科学院大学,北京100049 [4]国家荒漠-绿洲生态建设工程技术研究中心,乌鲁木齐830011

出　　处：《生态学报》2017年第5期1506-1514,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41271341;41030530;41301038);塔里木油田公司项目(971012080007);水利公益性行业科研专项(201401049)

摘　　要：为探讨沙漠公路防护林地表凋落物的分解速率和养分释放动态对施肥的响应,采用凋落物分解袋法,对塔里木沙漠公路防护林地乔木状沙拐枣(Calligonum arborescens)同化枝、梭梭(Haloxylon ammodendron)同化枝和多枝柽柳(Tamarix ramosissima)枝凋落物在施肥处理下的分解及养分释放特征进行研究。结果表明:经过420d的分解,3种凋落物质量残留率在对照(不施肥)、施用氮肥、施用磷钾复合肥处理间存在显著性差异(P<0.05)。乔木状沙拐枣同化枝、梭梭同化枝和多枝柽柳枝在对照处理下的质量残留率分别为56.95%、31.32%和50.24%。施肥处理下3种凋落物均呈现出梭梭同化枝分解速率最快,多枝柽柳枝次之,乔木状沙拐枣同化枝分解最慢。施用磷钾复合肥极显著提高了3种凋落物的分解速率(P<0.01);施用氮肥则促进多枝柽柳枝的分解,抑制乔木状沙拐枣和梭梭同化枝的分解。凋落物分解过程中,对照组3种植物凋落物的C、N、P和K元素均呈现净释放状态;施肥后凋落物的N、P和K元素呈现出富集-释放的模式。凋落物初始P含量和C/N、C/P比值是分解初期的主导因素,初始K、木质素、纤维素含量和C/N、木质素/N比值是分解后期的主要控制因素。研究表明,施肥显著影响沙漠公路防护林地表凋落物的分解,增加防护林地表凋落物的养分归还量,延后养分释放的时间,改善塔里木沙漠公路防护林地的土壤肥力。凋落物初始C/N比值是预测塔里木沙漠凋落物分解的重要因素,且不同分解时期影响凋落物分解的初始化学组成有所差异。Litter decomposition determines the nutrient and carbon cycling processes and regulates nutrient return to the soil in many terrestrial ecosystems. Wood plant litter decomposition is a crucial biogeochemical process for carbon and nutrient cycling, especially in arid and nutrient-constrained ecosystems. However, the role of litter decomposition in extreme drought deserts and the determining factors remain debatable and poorly understood. The Tarim Desert Highway Shelterbelt consists of three artificial plant species that account for the majority of net primary productivity, and their litters are the major contributors to carbon and nutrient recycling. In such artificial desert shelter forests, the addition of fertilizer causes contradictory effects on litter decomposition and nutrient dynamics. This study aims to （1） examine how the addition of fertilizer affects surface litter decomposition and nutrient dynamics, and （2） determine the major factors influencing litter decomposition in arid deserts. The litterbag method was used to investigate the assimilative branches decomposition of Calligonum arborescens and Haloxylon ammodendron, and the branches decomposition of Tamarix ramosissima in the Taklimakan Desert Research Station. Filled litterbags were placed on soil surfaces at different plots in March 2013. Fertilizer addition and irrigation were implemented from March to November during the experiment. Litterbags were collected in May, July, September, and November of 2013, and in March and May of 2014. The mass remaining, elemental content （carbon, nitrogen, phosphorus, and potassium）, and decomposition rates of litter were analyzed at each decomposition stage. Results showed that after 420 days of decomposition, significant differences were found among control （without fertilizer）, addition of nitrogen fertilizer, and phosphorus and potassium compound fertilizer treatments. The mass remaining for the assimilative branches of C. arborescens, assimilative branches of H. ammodendron, and branches

关 键 词：质量残留率 分解速率 养分 施肥 沙漠公路防护林 

分 类 号：S714[农业科学—林学]