豫西丘陵坡地弃耕农田植被演替对土壤碳、氮库的影响  

Effects of vegetation succession on soil carbon and nitrogen storage in abandoned hilly farmlands of the Western Henan Region

作　　者：赵威[1] 李亚鸽[1] 亓琳[1,2] 李琳 王馨[1] ZHAO Wei;Li Yage;QI Lin;LI Lin;WANG Xin(College of Agriculture/College of Tree Peony,Henan University of Science and Technology,Luoyang 471023,China;State Key Laboratory of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China)

机构地区：[1]河南科技大学农学院/牡丹学院,洛阳471023 [2]中国科学院生态环境研究中心城市与区域生态国家重点实验室,北京100085

出　　处：《生态学报》2018年第19期7016-7025,共10页Acta Ecologica Sinica

基　　金：NSFC-河南人才培养联合基金(U1304306);中国科学院战略性先导科技专项(XDA05050402);河南科技大学第六届研究生创新基金(CXJJ-2016-ZR12)

摘　　要：在豫西丘陵坡地弃耕农田中,设置一个时间梯度为1,3,8,15,25 a的弃耕演替系列,调查其群落数量特征、物种组成、植被与土壤的碳、氮储量,分析群落的自然次生演替过程,并探讨土壤碳库与氮库对植物群落演替的响应机制。结果表明,弃耕农田群落演替缓慢,阶段性不明显,大致可划分为一、二年生草本→多年生草本+灌木两个阶段。定植物种的多样性变化与附近的原生植被有关。在25 a的演替进程中,草本植物始终占据优势,旱生植物数量约是中生植物的4倍,C3植物数量逐渐增多;群落α多样性指数呈先增大后减小趋势,Margalef丰富度指数、Pielou均匀度指数与Shannon-Wiener综合多样性指数最大值分别为1.53、0.95、2.18,表明弃耕农田的自然演替促使群落结构更加复杂并趋向稳定。群落植物的碳、氮储量随着生物量的增加而增加,在25 a时分别达到313.14 g/m^2和11.69 g/m^2。土壤碳储量与氮储量的变化相反,在演替后期(25 a)土壤碳储量增加到960.98 g/m^2,而氮储量则降低至27.08 g/m^2,表明豫西弃耕农田土壤具有"固碳放氮"的生态现象。RDA分析表明,群落盖度、密度和生物量是影响土壤碳、氮储量的主要因子。从群落的生态功能变化分析,按照弃耕演替时间推进,土壤碳储量逐渐增大,有利于生态系统碳固定;而土壤氮库的缩减则不利于群落的稳定,建议增加群落中豆科植物的丰富度,从而促进土壤氮素固定,缓解氮素流失。Understanding the vegetation, soil status, and their relationship on abandoned farmland plays an important role in the determination of future land use. In this study, five hilly farmlands abandoned for different periods of time （ 1, 3, 8, 15, and 25 years） were selected as a series of successive abandonments in the Western henan region to investigate the quantitative characteristics and species composition of the plant community and the carbon and nitrogen storage in vegetation and the soil, to analyze the natural secondary succession process of the plant community, and to discuss how the soil carbon and nitrogen pool responded to the plant community succession. The main results indicated that： The abandoned farmland communities that possessed a slow succession progress and generally included two indistinct succession stages, from annual or biennial herbs to perennial herbs and shrubs. The plant species diversity was closely related to the surrounding native vegetation. Over 25 years, herbs in the community always had an advantage status, the number of xerophytes was more than four times that of mesophytes, and the quantity of C3 plants increased gradually. The c~ diversity index first increased and then decreased, and the maximum values of the Margalef, Pielou and Shannon-Wiener indices were 1.53, 0.95, and 2.18, respectively. These data could provide proof that the community structure became more complex and stable after a natural succession process of 25 years. Both plant carbon storage and nitrogen storage increased as the community biomass constantly accumulated, reaching values of 313.14 g/m2 and 11.69 g/m2, respectively, at the 25-year succession stage. The soil carbon storage trend opposed that of soil nitrogen storage. In the climax stage （ 25 a） , the soil carbon storage increased to 960.98 g/m2, whereas the soil nitrogen storage was reduced to 27.08 g/m2. Therefore, the changes in the soil property of the abandoned farmlands in the Western henan region resulted in the ecological phenomenon o

关 键 词：弃耕农田 次生演替 生物多样性 生物量 碳、氮储量 

分 类 号：S153.6[农业科学—土壤学]