Roots Spatial Distribution Characteristics Of M9T337 Dwarfing Self-rooted Rootstock Apple Trees From Different Ages

The Loess Plateau belongs to the temperate monsoon climate,enjoying the advantages of long exposure time to the sun,dramatic differences of the day and night temperatures,and deep soil layer,which is beneficial to drainage.Therefore,it is one of the two major apple producing areas in China.During recent years,the intensive cultivation techniques of dwarfing self-rooted apple trees are widely used in the development and application all over the world.The important development direction of intensive cultivation of modern apple dwarfing self-rooted apple trees is water and fertilizer integration.During recent years,Shaanxi has adjusted the fruit industry and has now developed into the region with the largest area of apple dwarfing self-rooted apple tree.Although the uniform of dwarfing rootstocks growth can control the growth of ‘Fuji’ apple trees and its fruiting as well.However,due to the shallow distribution of T337 roots from rootstock and the limitation of drip irrigation water and fertilizer space,the current water and fertilizer absorption regularities of this type of orchard still remain unclear.As a result,there may be weak or vigorous growth in production.Therefore,the company cooperative orchards have more urgent needs regarding how to accurately manage water and fertilizer.The premise of precise water and fertilizer management is to understand the distribution of root system,and then provide basic data support for the establishment of root water absorption function.Therefore,in this study,the root samples were taken by mechanical root drill and analyzed by soil root scanner.Meanwhile,the number,composition and distribution of roots of ‘Fuji’ apple trees in different ages of Qianyang county,Shaanxi,in the three-dimensional space were studied systematically.For dwarfing self-rooted rootstock apple orchard water and fertilizer precision management,to provide a theoretical basis for improving the yield and quality of apple orchard.The main results are as follows:1.The root length density and root surface area density of dwarf self-rooted apple roots increased first and then decreased with the increase of tree age.2.The spatial distribution of roots of dwarf self-rooted apple trees is regular: The roots are mainly distributed at 0-65 cm from the horizontal direction of the trunk,and concentrated in the underground 0-60 cm soil layer.As the age of the tree increases,the root distribution range is wider,but the total volume of the root system expands slowly in the horizontal direction,significantly moved down in the vertical direction.3.The root length density of roots showed an exponential decay in both horizontal and vertical directions;by establishing a two-dimensional root density equation,the root distribution of three tree-aged dwarf rootstocks was in line with the two-dimensional exponential distribution.