| Feldspathic sandstone area is one of the areas with the most serious soil erosion in China,severe soil erosion and harsh natural conditions,resulting in the decline and death of H.rhamnoides planted forest,greatly reducing the water and soil conservation function of H.rhamnoides,how to effectively promote H.rhamnoides renewal and rejuvenation,rational use of local water resources has gradually become a hot spot in feldspathic sandstone area research.Stumping is a technical means of artificially shearing plants from the ground or root system with tools or instruments to stimulate the secondary growth of plants,and the effect is better for plants with tiller characteristics.In this context,this thesis took the H.rhamnoides plantation in the Qiugou watershed of Junger Qiuzu in Inner Mongolia as the research object,and set up four kinds of stumping 0cm,10 cm,15cm and20 cm with unflat stumping H.rhamnoides as the control stumping height,and continuously measured the physiological and ecological indicators of H.rhamnoides during the growing season: plant height,crown width,ground diameter,number of new shoots,and length,number and diameter of branches at all levels.At the same time,the physiological indexes of H.rhamnoides leaves were continuously monitored: common gas exchange parameters such as net photosynthesis rate(Pn),transpiration rate(Tr)and stomatal conductance(Gs);and the stem flow rate(SF)of H.rhamnoides was monitored simultaneously.The effect of stumping height on H.rhamnoides morphological characteristics,clade configuration characteristics,leaf morphological characteristics,physiological characteristics and stem flow characteristics was discussed,the physiological and ecological indicators and liquid flow indicators of H.rhamnoides were comprehensively analyzed and screened for the optimal stumping height,and a water consumption prediction model was established and verified,in order to provide a theoretical basis for the construction of H.rhamnoides plantation in feldspathic sandstone area.The main conclusions are as follows:(1)Effect of stumping on growth characteristics of H.rhamnoidesThe plant height,crown width,ground diameter and number of new shoots of H.rhamnoides after stumping treatment increased significantly higher than that of H.rhamnoides without stumping.The number of hierarchical branches of H.rhamnoides with a stumping height of 15 cm was the largest,and the branch length,branch diameter and branch diameter ratio at all levels were the largest.(2)Effect of stumping on physiological characteristics of H.rhamnoidesThe Pn,Tr,Gs and WUE of H.rhamnoides after stumping treatment were significantly improved compared with that of H.rhamnoides without stumping.The height of the stumping is 15 cm,and the H.rhamnoides is higher than that of other stumping treatment.(3)Effect of stumping on stem flow characteristics of H.rhamnoidesThe flow activity of H.rhamnoides after stumping treatment was stronger in the early morning and night from May to July,and weakened during the day.The average flow rate,total fluid accumulation and diurnal accumulation of H.rhamnoides with a stumpin height of 15 cm were higher than those of other stumpin treatments.(4)Screening of optimal stumping height of H.rhamnoides and establishment and verification of water consumption modelThe water consumption predicted by the water consumption model of H.rhamnoides at the height of the stumping and the water consumption measured in the field test have a small error rate,the water use efficiency is the highest,and the overall water consumption is small,which is conducive to water saving and good restoration of plantations,so it can be irrigated month by month according to the predicted water consumption. |
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