2年生毛白杨细根生长、分布及形态特征对滴灌水氮耦合的响应  

Coupling effects of drip irrigation and nitrogen fertigation on fine root growth,distribution and morphological characters of 2-year-old Populus tomentosa plantations

作　　者：贺曰林 李广德[2] 席本野[1] 戴腾飞[1] 贾黎明[1] He Yuelin;Li Guangde;Xi Benye;Dai Tengfei;Jia Liming(Key Laboratory for Silviculture and Conservation of Ministry of Education,Beijing Forestry University,Beijing 100083,China;Faculty of Agriculture,Forestry and Medicine,the Open University of China,Beijing 100039,China)

机构地区：[1]北京林业大学省部共建森林培育与保护教育部重点实验室,北京100083 [2]国家开放大学农林医学教育部,北京100039

出　　处：《北京林业大学学报》2022年第4期1-11,共11页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(31670625);国家重点研发计划(2016YFD0600403);城乡生态环境北京实验室-北京乔木类乡土植物筛选及高效繁育技术(200-67191003)。

摘　　要：【目的】三倍体毛白杨作为华北平原重要的速生丰产树种之一,是我国木材战略储备的重要资源。滴灌水氮耦合技术已被广泛应用于人工林培育,掌握该栽培技术下毛白杨幼林细根生长、分布及形态特征,明确影响细根生长的重要环境因子,对精准水氮耦合策略的制定具有重要意义。【方法】以砂壤土立地条件下2年生毛白杨为研究对象,设置由-20 kPa(W20)、-33 kPa(W33)、-45 kPa(W45)3个灌溉水平和0(N0)、80 kg/(hm^(2)·a)(N80)、150 kg/(hm^(2)·a)(N150)、220kg/(hm^(2)·a)(N220)4个施氮水平组成的12个水氮耦合处理,并设置无灌溉施肥的对照处理,监测特定水氮耦合处理下(W20N220、W20N80、W20N0、W45N220、W45N0)幼林细根生长、分布及形态指标的变化规律,并分析对应土层土壤有机质、全氮、铵态氮、硝态氮及土壤含水率与细根生长的关系。【结果】(1)滴灌水氮耦合及土层深度对细根生长及形态指标有显著影响(P<0.05)。其中,W20处理能显著促进0~20 cm土层细根生长(P<0.05),细根趋于浅土层分布,而在W45N0处理下,0~30 cm土层比根长显著提高(P<0.05)。(2)垂直剖面内,W20处理细根呈“由表层至深层降低”的分布规律,W45处理细根在不同土层内分布较均匀;水平方向上,细根分布呈“靠近树体,随径向距离增加而降低”的分布规律,但W20N220和W45N0处理细根生物量在同一径向位点无显著差异。(3)有机质、铵态氮和硝态氮均与细根生长呈显著的正相关关系(P<0.05),且相关性强弱的顺序为有机质>硝态氮>铵态氮。【结论】W20滴灌施肥处理能显著促进表土层细根生长,不同施氮量对细根性状无明显影响;三倍体毛白杨优先改变细根生物量在不同土层的分配及部分形态特征,而非改变细根总生物量以适应水氮资源的异质性;滴灌水氮耦合措施实施的过程中,应采取少量多次的灌溉施肥方式对0~30 cm细根集中分布土层及时�[Objective]As one of the important fast-growing and high-yielding species in the North China Plain,the triploid Populus tomentosa is an important resource for the timber reservation strategy of China.Drip irrigation and nitrogen fertigation(DIF)technique has been widely used in plantation cultivation.Figuring out the responses of fine root growth,morphology traits and distribution pattern to DIF practices,and identifying the important environmental factors affecting fine root growth are of great significance for the formulation of precise water-nitrogen coupling strategies.[Method]The plant materials were 2-year-old P.tomentosa plantations on the sandy loam soil,and twelve DIF treatments were a factorial combination of three irrigation levels(-20 kPa(W20),-33 kPa(W33),-45 kPa(W45))and four fertigation levels(0(N0),80 kg/(ha·year)(N80),150 kg/(ha·year)(N150),220 kg/(ha·year)(N220)),and the control treatment was with no irrigation and no fertigation.We monitored fine root traits and distribution patterns in 5 treatments,including W20 N220,W20 N80,W20 N0,W45 N220 and W45 N0.Besides,we did the correlation analysis of soil properties(organic matter,total nitrogen,ammonium nitrogen,nitrate nitrogen,and soil water content)and fine root growth traits.[Result](1)DIF treatments and soil depth had significant effects on fine root growth and morphology traits(P<0.05).W20 associated treatments significantly stimulated fine root growth in 0-20 cm soil layers(P<0.05),and the fine root accumulated in the shallow soil layers.The specific root length was significantly higher in 0-30 cm soil layers in W45 N0 treatment(P<0.05).(2)Fine root accumulated in the shallow soil layers and decreased with the increment of soil depth in W20 associated treatments,in contrast with the relatively uniform vertical distribution in W45 associated treatments.Fine root biomass accumulated near the trunk and decreased as the horizontal distance increased,and there was no significant difference of fine root biomass in W20 N220 and W45 N0 treatment i

关 键 词：水氮耦合 细根生长 细根形态 细根分布 土壤养分 毛白杨 

分 类 号：S792.117[农业科学—林木遗传育种]