Comparative Analysis And Simulation Of Soil Moisture Infiltration Characteristics In Different Communities In The Forests Of Tianshan Mountains,China

Soil infiltration characteristic is an important link that affects forest ecological hydrological processes.To compare differences in soil-water infiltration characteristics of different community types,the double cutting ring device and cutting ring method were used to analyzed natural forests,plantations,gap grasslands,grasslands,forest edge shrubs,and piedmont shrubs on the northern slope of the Tianshan Mountains.The effects of soil physical and chemical properties,such as organic matter content,capillary porosity,bulk density,and water content,on the infiltration process were compared and analyzed.Several common models were used to simulate the infiltration process,and the suitability of these models in the area was analyzed and compared.Observation and simulation of the soil-water movement process of different community types can provide a useful reference for the long-term observation of ecological hydrology in the forest areas of Tianshan.The results were as follows:(1)There are some differences in soil physicochemical properties between six community types,which show that the soil bulk density is also different between the soil layers of the same community type,and all show an increase trend with the increase of soil depth.Both capillary water-storage capacity and maximum water-storage capacity decrease with the increase of the soil layer.There was no particularly large difference in soil moisture content in each soil layer,but the water content of 0–20 cm layer was higher than that of other layers overall.The content of soil organic matter was quite different,and the organic matter content of soil layer in natural forests was larger than that of five other community types.(2)The soil infiltration performance of the six community types showed the same trend: initial infiltration rate>average infiltration rate>stable infiltration rate.The initial infiltration rate of the soil in the first 60 min in the six main community types was 2.63–9.00 mm/min,and the stable infiltration rate was 0.85–5.12 mm/min.The average soil infiltration rate of the different community types ranged from high to low as follows: natural forest>forest edge shrub>gap grassland>grassland>artificial forest>piedmont shrub.(3)The results of infiltration fitting results show that Kostiakov model's coefficient of determination is between 0.48 and 0.97,and in the Horton model,the determination coefficient is close to or above the 0.90;Philip model,which is between 0.57 and 0.86,except the plantations and grasslands,and the suitability is poor.The Kostiakov model had a high fitting precision for the soil infiltration process of the six community types and was suitable for describing the soil infiltration characteristics of the water conservation forests in this study area.(4)Soil organic matter content was positively correlated with soil infiltration rate,and reached a very significant level with initial infiltration rate,while soil moisture content,soil capillary porosity and soil bulk density were significantly negatively correlated with soil infiltration capacity.The results of correlation analysis of soil permeability parameters measured by cutting ring method showed that the content of soil organic matter was positively correlated with soil infiltration rate(initial infiltration rate,stable infiltration rate and average infiltration rate).And the initial infiltration rate reached a very significant level.Soil capillary porosity was negatively correlated with soil infiltration rate,significantly negatively correlated with average infiltration rate and extremely significantly negatively correlated with initial infiltration rate.There was a negative correlation between soil bulk density and soil infiltration capacity,and there was a significant negative correlation between soil bulk density and initial infiltration rate.The soil moisture content is negatively correlated with the infiltration process.The larger the soil initial water content is,the lower the initial infiltration rate is.It can also be said that in the case of the same soil structure,there is an inverse relationship between soil infiltration rate and soil water content,which decreases with the increase of soil water content until stable infiltration.(5)For the same community type,the infiltration rate measured by the double cutting ring device was higher than that by the cutting ring method.It indicates that there is a certain error in instrument measurement.