Effects Of Different Stubble Height On Fine Root Growth And Physiological Characteristics Of Hippophae Rhamnoides In Feldspathic Sandstone Area

In this study,Hippophae rhamnoides plantation in Geqiugou Valley of Zhungeer Banner,Inner Mongolia was taken as the research object,and 4 stubble heights,namely0 cm,10cm,15 cm and 20 cm,were set as the control,the response law of the growth and physiological characteristics of Hippophae rhamnoides fine roots to stubble height were explored.The growth and physiological indexes of Hippophae rhamnoides fine roots were comprehensively analyzed,so as to provide a theoretical basis for the construction of artificial forest land of Hippophae rhamnoides in the feldspathic sandstone area.The results showed that:(1)There were significant differences between 4 treatments and the control(P<0.05).With the increase of stubble height,the fine root biomass of Hippophae rhamnoides showed a trend of increasing first and then decreasing,namely stubble 15cm> stubble10cm> stubble 0cm> stubble 20cm> control.The ratios of fine root biomass to total biomass of Hippophae rhamnoides 40-50 cm away from the standard bush in the four flat stubble treatments were 0.25%,0.79%,1.11% and 0.52% higher than those of the control,respectively.The ratios of fine root biomass to total biomass of Hippophae rhamnoides with horizontal distance of 80-100 cm were 0.19%,0.66%,1.78% and 0.45% higher than those of control,respectively.The results indicate that the stubble measures are beneficial to the development of Hippophae rhamnoides fine roots into deep soil in both vertical and horizontal directions.(2)There were significant differences in growth rate,death rate and ratio of life to death of Hippophae rhamnoides between different stubble treatments and control(P<0.05),namely stubble 15cm> stubble 10cm> stubble 0cm> stubble 20cm> control.The dynamic growth parameters of Hippophae rhamnoides fine roots showed a certain seasonal pattern from May to September.The growth rate of fine roots in each treatment showed a single peak trend of first increasing and then decreasing,reaching the highest in August;the root length density and surface area density of Hippophae rhamnoides fine roots in each stumping treatment increased continuously with the increase of months,while the control showed a trend of increasing first and then decreasing.The death rate of each treatment continued to increase with the increase of month,and the ratio of life to death continued to decrease with the increase of month.The growth parameters of Hippophae rhamnoides fine roots showed a single-peak trend of first increasing and then decreasing with the increase of soil depth,and there were significant differences between 10-20 cm soil layer and others soil layers(P<0.05).(3)There were significant differences in proline,activity,soluble sugar,membrane permeability and malondialdehyde between Hippophae rhamnoides fine root and control(P<0.05).The results showed that proline,membrane permeability and malondialdehyde from high to low were as follows: control > stubble 20cm> stubble 0cm> stubble 10cm>stubble 15 cm.Fine root vigor and soluble sugar of each stubble treatment from high to low were as follows: stubble 15cm> stubble 10cm> stubble 0cm> stubble 20cm> control.There were significant differences in physiological indexes of seabuckthorn fine roots among different treatments in month and soil layer(P<0.05).In conclusion,the biomass of Hippophae rhamnoides fine roots increases significantly,the metabolism and turnover rate of fine roots acceleratess,and the root activity is significantly improved after stumping.Moreover,stumping can effectively reduce the effect of drought stress on fine roots.The results show that the indexes of Hippophae rhamnoides fine roots with different stubble height are the best.