果园间作模式下杏树与苜蓿的根系分布特征及其土壤理化性质研究

Characteristics of Root Distributions of Prunus armeniaca and Medicago sativa and Soil Physical and Chemical Properties under Orchard Intercropping Mode

该研究采用田间小区试验,设计杏树(Prunus armeniaca)下清耕(CK)和杏树间作紫花苜蓿(T)2个处理,实地采集测定各样地不同土层紫花苜蓿的根系生物量以及杏树的侧根系生物量,并测定土壤pH、电导率及其土壤有机质和速效氮含量,分析果园间作模式下紫花苜蓿对果树侧根系垂直分布特征及其土壤理化性质的影响,为果园间作苜蓿模式的推广提供理论依据。结果表明:(1)CK与T处理下的杏树侧根生物量在土壤中的垂直分布都主要集中在20~60cm土层,其生物量分别为750.8g和737.6g,分别占总侧根生物量的64.4%和64.5%;紫花苜蓿根系生物量分布呈倒金字塔型,且主要分布在0~40cm土层(166.3g),其中0~20cm土层的根系生物量最高(97.4g),占根系总生物量的35.8%。(2)与CK处理相比,T处理可有效增加果园表层土壤的有机质含量、速效态氮含量、硝态氮含量和铵态氮含量,其中,在0~20cm土层分别显著增加17.1%、40.8%、28.5%和40.8%,在20~40cm土层分别显著增加36.1%、23.1%、60.2%和23.8%,并显著降低了表层土壤电导率,但对土壤pH无显著影响。研究认为,杏园间作牧草紫花苜蓿虽然杏树与苜蓿根系会发生较小资源的竞争,但有利于改善林下土壤的理化性质和养分状况,能够有效促进果树的生长发育。

As a modern orchard soil management system at present,the intercropping Medicago sativa(M.sativa)model has been widely used in the orchards management at home and abroad.In this study,two treatments were designed for the clean tillage of Prunus armeniaca(P.armeniaca)(CK)and P.armeniaca intercropping M.sativa(T)in the field experiment.We measured the M.sativa root biomass and P.armeniaca lateral root biomass,and soil pH,conductivity,soil organic matter and available nitrogen content in all kinds of soil layer to analyze the influence of orchard intercropping mode on vertical distribution characteristics of P.armeniaca lateral root biomass and M.sativa root biomass,and soil physical and chemical properties,for the sake of providing theoretical basis for the orchard intercropping mode.The mayor results showed:(1)the vertical distributions of P.armeniaca lateral root biomass under both CK and T treatments mainly concentrated in the20to60cm,the P.armeniaca lateral root biomasses of CK and T treatments were750.8g and737.6g,accounting for64.4%and64.5%of the total iateral root biomass,respectively.The distribution of M.sativa root was gold tower type,mainly distributed in soil layer of0to40cm,and the biomass of M.sativa root in soil layer of0to40cm was166.3g,the biomass(97.4g,accounting for35.8%of the total root biomass)was the highest in soil layer of0-20cm.(2)Compared to CK treatment,T treatment could effectively increase the contents of organic matter,available nitrogen,nitrate nitrogen and ammonium nitrogen of the surface soil in orchard.In0-20cm soil layer,they significantly increased17.1%,40.8%,28.5%and40.8%,respectively.In the20-40cm soil layer,they significantly increased36.1%,23.1%,60.2%and23.1%,respectively.T treatment and effectively reduced electrical conductivity of the surface soil,but did not significantly reduce pH of the surface soil.Therefore,the research suggested that fruit trees compete with M.sativa root was relatively small,but the intercropping grass could improve the physical and chemical properties undergrowth soil,and could promote the growth of fruit trees.