宽行密植模式对旱区黄冠梨根系构型的影响

Effects of wide-row and dense-planting pattern on root architecture of Huangguan pear in arid region

【目的】筛选宽行密植栽培模式的适宜定植密度,为合理高效利用土壤资源和水肥精准化管理提供参考。【方法】以甘肃省干旱区不同宽行密植模式(株行距1.0 m×4.0 m、1.5 m×4.0 m、2.0 m×4.0 m)下的黄冠梨为研究对象,利用Win-RHIZO根系分析系统,对根系的构型参数进行测定,对比分析不同径级((φ>2 mm和φ≤2 mm))根系的分布与吸收范围,【结果】不同栽培模式下单位面积的群体数量的差异导致根系功能和结构的显著变化,0~20 cm土层是株行距1.0 m×4.0 m处理根系的集中分布区域,比根长、比根面积和总根体积均显著高于株行距2.0 m×4.0 m处理。在20~40 cm土层,株行距1.5 m×4.0 m处理的比根长较其他处理提升了3.7%~26.8%,第2年比根面积较株行距1.0 m×4.0 m处理提升了82.1%,株行距2.0 m×4.0 m处理根体积和根尖数量较株行距1.0 m×4.0 m处理分别提升了62.3%和34.2%。在40~60 cm土层,株行距2.0 m×4.0 m处理的比根长、比根面积、根长密度较株行距1.0 m×4.0 m处理最高分别增加了38.5%、95.5%和175.0%。栽植密度由大变小时,根系(φ>2 mm)集中分布现象逐渐减轻,水平分布扩展距离由近到远逐渐减小,且根系垂直与水平分布的差异减小。【结论】株行距1.0 m×4.0 m处理下细根(φ≤2 mm)分布离散度大,偏向性分布特点突出,垂直分布集中于表层土壤,根长、根表面积和根尖数量占比均超过50%,根系构型“浅表化”明显,株行距1.5 m×4.0 m处理细根的水平和垂直分布较均衡,但根长和根表面积均显著减小,吸收能力减弱,株行距2.0 m×4.0 m处理细根的分布明显向深层和离树干较远的区域扩展,根系的吸收能力显著增强,根系构型较好。

【Objective】The selection of suitable planting densities for the wide-row and dense-planting pattern provided a reference for the rational and efficient utilization of soil resources and precise management of water and fertilizer.【Method】The Huangguan pear under different cultivation densities in wide-row and dense-planting pattern(row spacing 1.0 m×4.0 m,1.5 m×4.0 m,2.0 m×4.0 m)in the arid area of Gansu province was taken as the research materials.Using the Win RHIZO root analysis system,the configuration parameters of the root system were measured,and the distribution and absorption range of roots with different diameter grades(φ>2 mm andφ≤2 mm)were compared and analyzed.【Result】The difference in population size per unit area under different cultivation modes led to significant changes in root function and structure.The 0-20 cm soil layer was the concentrated distribution area of roots with a row spacing of 1.0m×4.0m,and the specific root length(SRL)and specific root area(SRA)and root volume(VA)were significantly higher than those in the treatment with a row spacing 2.0 m×4.0 m.In the 20-40 cm soil layer,the SRL of row spacing 1.5 m×4.0 m treatment increased by 3.7%-26.8%compared with other treatments.In the second year,the SRA increased by 82.1%compared to the treatment with row spacing 1.0 m×4.0 m.The root volume and root tip number of the treatment with row spacing of 2.0 m×4.0 m increased by 62.3%and 34.2%,respectively,compared to the treatment with a row spacing of 1.0 m×4.0 m.In the soil layer of 40-60 cm,the SRL,SRA and RLD of 2.0 m×4.0 m treatment increased by 38.5%,95.5%and 175.0%respectively compared to the treatment with a row spacing of 1.0 m×4.0 m.The centralized distribution of roots(φ>2 mm)gradually decreased,and the horizontal distribution and expansion distance gradually reduced from near to far,Additionally,the difference between vertical and horizontal distribution of roots decreased as the plant density changed from large to small.【Conclusion】Under row spacing 1.0 m×4.0 m treatment,the distribution of fine roots(φ≤2 mm)had a high degree of dispersion and prominent biased distribution characteristics.At the meantime,the vertical distribution was concentrated in the surface soil,with root length,root surface area and root tip number accounting for 50%of the total,and the root system configuration was significantly“superficialized”.Moreover,the horizontal and vertical distribution of fine roots was balanced,but the SRL,SRA and absorption capacity of fine roots were significantly decreased under row spacing 1.5 m×4.0 m treatment with leading to reduce the root absorption capacity.Furthermore,the distribution of fine roots in row spacing 2.0 m×4.0 m treatment obviously expanded to the deeper and farther regions from the trunk,and the absorption capacity of roots was significantly enhanced.Therefore,the root architecture was suitable under row spacing 2.0 m×4.0 m treatment.