| The Pisha sandstone area is the concentrated source area of the Yellow River coarse sand,and it is also the area with the most serious soil and water loss in my country.The impact of soil is of great practical significance for scientifically guiding the vegetation construction in this area and reducing sediment into the yellow.In this thesis,the artificial Hippophae rhamnoides forests in the Pisha sandstone area of Inner Mongolia is studied,and the Hippophae rhamnoides forest is treated with stubble heights of 0cm,10 cm,15cm,and 20 cm from the surface(namely S1,S2,S3,and S4),and the unleveled plants are used as the control(CK),to study the effect of different stubble heights on the root architecture of Hippophae rhamnoides and its understory soil,and to analyze the correlation between root architecture and understory soil.The results show that:(1)There were significant differences in Hippophae rhamnoides root structure and soil physical properties among different stubble heights(P<0.05),except that the soil bulk density showed that the unleveled stubble>20cm stubble height>0cm stubble height>10cm stubble height> The stubble height of 15 cm,the root structure of sea buckthorn in different treatments and the indicators of the soil under the forest are all as follows: 15 cm stubble height > 10 cm stubble height > 0cm stubble height > 20 cm stubble height > unleveled stubble,of which the 15 cm stubble height The fractal dimension of the root system reached the maximum value,which was 1.385,and the fractal dimension of the root system of the unstubbed Hippophae rhamnoides was the smallest,which was 1.192.(2)The fractal dimension and root length of roots at all levels in different treatments showed the order of secondary lateral roots > primary lateral roots > main root.10-20 cm >0-10 cm > 20-30 cm > 30-40 cm > 40-50 cm,the soil bulk density showed an increasing trend with the increase of the soil layer,and the total pores,ventilation pores and ineffective pores all showed a decrease with the increase of the soil layer.Small trend.The proportion of root geometry and fractal characteristics in the soil layer is consistent,and the proportion of shallow layer is greater than that of deep layer,which also indicates that the root system of Hippophae rhamnoides in the feldspathic sandstone area is a shallow root type distribution.(3)Through the comparison of soil infiltration models under Hippophae rhamnoides forests with different stubble heights,the Kostiakov empirical model is more applicable.From the perspective of the branching rate and volatility of the dyeing degree,the dyeing branching rate and volatility of the unstubbed soil were the highest,of which the stubble height of 15 cm had the largest stained area of 54.35%,and the unstubbed soil had the smallest stained area of 32.48%.This indicated that the root system of Hippophae rhamnoides was more abundant after the stubble treatment,and the root activity resulted in a better soil preferential flow path,which enhanced the water holding and soil-fixing effect of the understory soil.(4)Principal component analysis and correlation heat map of Hippophae rhamnoides root architecture characteristics and understory soil physical properties of different treatments showed that each index of root system architecture and soil indexes were significantly correlated with different stubble heights,among which root index(fractal dimension,fractal abundance,root length,root volume,root nodule weight)were significantly positively correlated with soil indicators(porosity,>2mm aggregates,infiltration,stained area,water content),and bulk density was significantly correlated with both root and soil indicators.negative correlation.This shows that root growth and soil change are the relationship mechanism of interaction,and it has broad scientific and applied value to change root system configuration through stubble leveling measures to improve soil properties. |
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