不同林龄桉树人工林土壤团聚体稳定性及其影响因素  

Soil Aggregate Stability in Eucalyptus Plantations of Different Ages and Its Influencing Factors

作　　者：潘明华 蓝必布 李梁芬 廖慧球 莫柳萍 张喆 Pan Minghua;Lan Bibu;Li Liangfen;Liao Huiqiu;Mo Liuping;Zhang Zhe(Guangxi Zhuang Autonomous Region State-Owned Dagui Mountain Forest Farm,Hezhou,Guangxi 542899,China;College of Forestry,Guangxi University,Nanning,Guangxi 530004,China)

机构地区：[1]广西壮族自治区国有大桂山林场,广西贺州542899 [2]广西大学林学院,广西南宁530004

出　　处：《绿色科技》2023年第5期148-152,173,共6页Journal of Green Science and Technology

基　　金：广西国有大桂山林场桉树人工林地力维持策略研究(编号:202200100)。

摘　　要：桉树作为广西最常见的造林树种之一,具有高产、高质等优良特性。但由于长期纯林连栽,桉树人工林面临着地力衰退等突出问题,从而导致其产量、品质严重下降。土壤团聚体作为土壤结构的基本单元,能够为桉树生长提供良好的水、肥、气、热条件。因此,摸清桉树人工林土壤团聚体稳定性随林龄的变化规律及其影响因素,可为改善土壤结构、提升地力水平提供理论依据。为此,以广西国有大桂山林场为研究区域,选择幼龄(1 a)、中龄(2 a)、成熟龄(4 a)桉树人工林土壤以及邻近撂荒地土壤(CK)为研究对象。采集表层原状土样(0~20 cm),通过湿筛法将其分为>2 mm、1~2 mm、0.25~1 mm和<0.25 mm粒径团聚体,并计算了团聚体稳定性指数(MWD和GMD)。结果表明:林龄2 a之前,种植桉树有利于土壤>2 mm粒径团聚体的形成(组成比例由43.50%增加至56.14%),促进了团聚体稳定性升高;林龄2 a之后,土壤>2 mm粒径团聚体逐渐破碎(组成比例由56.14%减少至38.90%),导致了团聚体稳定性降低。在种植桉树过程中,土壤团聚体稳定性指数与土壤有机碳(P<0.01)、铁铝氧化物(P<0.01)、凋落物数量(P<0.05)呈正相关关系。总体而言,随着林龄的延长,桉树人工林土壤团聚体稳定性呈先升高后降低的变化趋势,且在林龄2 a时最高,说明种植桉树2 a时土壤具有稳定的团粒结构。As one of the most common afforestation species in Guangxi,Eucalyptus has excellent characteristics of high yield and quality.However,due to the long-term continuous planting of pure forest,Eucalyptus plantation is faced with outstanding problems such as soil decline,which leads to the serious decline of its yield and quality.Soil aggregates are the basic units of soil structures;stable soil structure can provide good water,fertilizer,air and heat conditions for Eucalyptus growth.Therefore,finding out the change law of soil aggregate stability and its influencing factors with stand age of Eucalyptus plantation can provide a theoretical basis for improving soil structures and raising fertility level.In this study,the State-Owned Dagui Mountain Forest Farm in Guangxi was selected as the research area,and the soil of young(1-year),middle(2-year)and mature(4-year)Eucalyptus plantation and adjacent abandoned land(CK)were selected as the research objects.The surface undisturbed soil samples(0~20 cm)were collected and divided into different sized aggregates(>2 mm,1~2 mm,0.25~1 mm and<0.25 mm)by wet sieve method,and the aggregate stability(as indicated by the values of MWD and GMD)was calculated.The results showed that before the stand age of 2 years,planting Eucalyptus was conducive to the formation of>2 mm aggregates(the proportion increased from 43.50%to 56.14%),and then the aggregate stability increased.However,after the stand age of 2 years,>2 mm aggregates were broken(the proportion decreased from 56.14%to 38.90%),which led to the decrease in the aggregate stability.In the process of Eucalyptus planting,soil aggregate stability was positively correlated with the soil organic carbon(P<0.01),Fe and Al oxide(P<0.01),and litter amount(P<0.05).In general,soil aggregate stability increased first and then decreased with stand age in Eucalyptus plantation,and the highest level was reached at the stand age of 2 years,indicating that the soil structure was stable in this stand age.

关 键 词：桉树人工林 林龄 团聚体组成 团聚体稳定性 影响因素 

分 类 号：S7[农业科学—林学]