干旱区骏枣根系分布和土壤养分关系分析

Research on the relationship between root distribution characteristics of Jun-jujube and soil nutrient in arid area

【目的】研究干旱区骏枣吸收根和输导根分布特征及其与土壤养分的关系。【方法】以阿拉尔垦区6年生骏枣为试材,采用剖面挖掘和分层取样法,使用WinRHIZO根系分析系统测定骏枣不同直径的根系根长、根表面积和根体积指标,并测定不同生长期(0~60 cm深度)土壤的碱解氮、速效磷、速效钾含量,分析根系分布与土壤养分的相关性。【结果】各土壤空间,吸收根根长密度始终高于输导根,根体积则相反。垂直方向上,吸收根和输导根根长密度和根表面积密度均随土层加深而下降,0~20 cm土层根系最密集,吸收根根长密度和根表面积密度占比分别为77.1%、76.5%,输导根占比为76.0%、74.6%。水平方向上,吸收根在0~20 cm和20~40 cm水平距离土壤密集分布,根长密度占比为20.0%~20.7%,根表面积密度占比20.0%~22.2%,输导根占比分别为21.8%~22.1%,18.4%~23.8%;40~140 cm水平距离土壤吸收根根长密度和根表面积密度占比8.8%~14.4%,输导根为8.7%~14.5%,吸收根根长密度和根表面积密度均随水平距离增加缓慢下降,输导根表现为上升下降往复变化,存在差异性。吸收根和输导根根长密度和根表面积密度与展叶期土壤碱解氮、幼果期碱解氮和速效磷相关系数大于0.820,吸收根根长密度和根表面积密度与展叶期土壤速效磷相关系数大于0.809,均表现极显著正相关性,根长密度和根表面积密度与速效钾成负相关关系,相关性不显著。【结论】骏枣根系分布较浅,0~20 cm深度、0~40 cm水平距离的土壤根系分布较为密集,是水分和养分利用的重要区域,根系在垂直方向分布与展叶期和幼果期土壤中的碱解氮和速效磷含量密切相关。

【Objective】To study the distribution characteristics of absorbing roots and conducting roots and their relationship with soil nutrients of Jun-jujube.【Methods】A six-year-old Jun-jujube in Aral reclamation area.The root length,root surface area and root volume of Jun-jujube with different diameters were measured by using the WinRHIZO root analysis system,and the contents of alkali hydrolyzable nitrogen,available phosphorus and available potassium in the soil(0-60 cm depth)in different growth periods were measured.In addition,the correlation between root distribution and soil nutrients was analyzed.【Results】In each soil space,the length density of absorbing root was always higher than that of conducting root,while the root volume was the opposite.In the vertical direction,the root length density and root surface area density of absorbing root and conducting root both decreased with the depth of soil layer,and the root density in 0-20 cm soil layer was the densest,with the proportion of absorbing root length density and root surface area density being 77.1%and 76.5%,respectively,and the proportion of conducting root being 76.0%and 74.6%,respectively.In the horizontal direction,the absorption roots were densely distributed in the soil at the horizontal distance of 0-20 cm and 20-40 cm.The proportion of root length density was between 20.0%-20.7%,the proportion of root surface area density was 20.0%-22.2%,and the proportion of conducting roots 21.8%-22.1%,18.4%-23.8%,respectively;The absorption root length density and root surface area density of the soil at the horizontal distance of 40-140 cm accounted for 8.8%-14.4%,and the transport root was 8.7%-14.5%.The absorption root length density and root surface area density decreased slowly with the increase of the horizontal distance,and the transport root showed upward and downward reciprocating changes,with differences.The correlation coefficient between the root length density and root surface area density of absorbing root and conducting root and soil alkali-hydrolyzable nitrogen and available phosphorus at the stage of leaf expansion was greater than 0.820,and the correlation coefficient between the root length density and root surface area density of absorbing root and soil available phosphorus at the stage of leaf expansion was greater than 0.809,showing a very significant positive correlation.The root length density and root surface area density had a negative correlation with available potassium,but the correlation was not significant.【Conclusion】The root distribution of Junzao jujube is relatively shallow,and the soil root distribution at the depth of 0-20 cm and the horizontal distance of 0-40 cm is relatively dense,which is an important area for water and nutrient utilization.The vertical distribution of root system is closely related to the content of alkali-hydrolyzable nitrogen and available phosphorus in the soil at the leaf expansion and young fruit stage.