| The southern mountainous area of Ningxia is located on the Loess Plateau,with deep valleys.Water is the most abundant and indispensable substance in plants,and soil moisture mainly depends on natural rainfall.Due to the particularity of the site conditions,the climate in this area is dry,water resources are scarce,soil erosion is serious,evaporation is strong,and the frequent small rainfall cannot penetrate into the roots of plants.In order to explore the response characteristics of soil moisture to rainfall and the root system of Hongmei and apricot economic forest in Nanning Mountains after the application of this device,a rainfall collection infiltration irrigation device integrating collection,storage and slow release was installed in the experimental area.Distribution law,tap the potential of small rainfall.Taking the economic forest of red plum and apricot with two conditions of installation of collecting infiltration irrigation device and natural bare land in the mountainous area of Ningnan as the research object,the rainfall response history of soil moisture in typical rainfall events in the study area was analyzed,and on this basis,the collection and infiltration irrigation was determined.The relationship between root soil moisture and root growth index and root distribution characteristics of 3-year-old Hongmei and apricot economic forest under the device.The research results provide a theoretical basis and scientific basis for the popularization and application of the collector infiltration irrigation device in arid and semi-arid areas.The main research results are as follows:(1)The average soil moisture content of the 30-40 cm soil layer when the collector and infiltration irrigation device is installed is the largest,and the average soil moisture content of each soil layer is higher than that of the bare land.During a rainfall,the coefficient of variation of natural bare land in different soil layers decreased sequentially from top to bottom,and the response of soil moisture to rainfall decreased layer by layer from top to bottom.The coefficient of variation of the installation of the collecting and infiltration irrigation device in different soil layers increases sequentially from top to bottom.(2)The coefficient of determination R2 of the linear equation of soil moisture and rainfall with the installation of the collector and infiltration irrigation device increases sequentially with the increase of the soil layer depth.In the 0-10 cm soil layer,the R2 is only 0.02,and the soil surface moisture has almost no response to rainfall,which confirms that the concentration The infiltration irrigation device can effectively reduce the evaporation of water on the soil surface and effectively improve the utilization rate of rainfall.(3)The study preliminarily determined that most of the fine roots of 3-year-old red plum and apricot were distributed between 20 and 40 cm.The root length density and root weight density of the installation of the collector infiltration irrigation device were higher than those of the bare land condition,and the root length density,root weight density and soil water content were higher.The change in specific root length was consistent with the change in soil moisture content.The roots of 3-year-old red plum apricot with larger than root length were mainly distributed in the soil layer of 30-40 cm.In the case of the installation of the collector and infiltration irrigation device,the root length density and soil moisture content showed a very significant correlation,and the correlation coefficient was 0.995.The correlation coefficient between the two is 0.824.(4)The soil moisture content curve of the installed rainfall collecting and infiltration irrigation device showed a very obvious "step" rise at L20D25 and L20D35,and the tree height of the installed rainfall infiltration irrigation device was significantly correlated with the ground diameter and leaf area index.relationship,the correlation coefficients were 0.810 and 0.667,respectively.There was a significant or extremely significant positive correlation between ground diameter and leaf dry weight;there was also a significant positive correlation between ground diameter and plant height There is also a good correlation between ground diameter and leaf area index,and the correlation coefficient is 0.725;the height of red plum and apricot trees in the natural bare ground has a very significant correlation with ground diameter and leaf area index,and the correlation coefficients are respectively were 0.691 and 0.546,there was a very significant correlation between ground diameter and leaf area index,and the correlation coefficient was 0.749. |
PDF Full Text Request