Carbon And Nitrogen Contents And Changes Of Main Forest Soil Types In Sichuan Province

Forest soil is the most important storage of carbon and nitrogen,and it also plays a role in the source and sink of carbon and nitrogen.Carbon and nitrogen cycle processes have a significant impact on the structure and function of forest ecosystems.They also have a particularly important impact on global climate change and the human living environment.They also manage and manage forest ecosystems and maintain the health of ecosystems.It is of great significance to understand its influence mechanism on future climate.Based on the survey data of the main forest soil types in Sichuan Province,this study investigated the contents and characteristics of total carbon and total nitrogen in the main forest soils of Sichuan Province,studied the laws of differentiation,and analyzed the temperature,precipitation,elevation,soil texture,and the main forest soils.The relationship between carbon and total nitrogen density.The main conclusions are as follows:(1)There is a positive correlation between the soil bulk density and the soil depth.The greater the soil depth,the greater the bulk density.Among different types of forest soils,the coefficient of variation of soil bulk density at each level differs significantly,and the greater the soil depth,the smaller the difference in bulk density between soil types.Powder particles are more evenly distributed in different soil layers of the same soil type.In different soil layers of the same soil type,the clay content changes little with the increase of soil depth.In different soil layers of the same soil type,the content of sand varies greatly,and different soil types show different distribution patterns.(2)The minimum nitrogen content in red soil is 0.058%,and the highest nitrogen content in mountain meadow soil is 0.166%;the nitrogen content of forest soil in the mountainous areas in the Sichuan Basin is significantly higher than that in the Sichuan Basin.The average nitrogen content of forest soils in the surrounding mountainous areas was greater than 0.1%,while the average nitrogen content in forest soils in the basins was lower than 0.1%.The lowest carbon content of alpine cold desert soil is 0.911%,and the highest carbon content of mountain meadow soil is 2.538%.The carbon content of forest soil in the mountainous areas around the Sichuan Basin is significantly higher than that of the Sichuan Basin,including the basin.The average carbon content in forest soils in surrounding mountainous areas was greater than 1.2%,while the average carbon content in forest soils in the basins was lower than 1.2%.The differences in nitrogen content and carbon content between the same soil layers in different soil types were analyzed,and there were significant differences in nitrogen content and carbon content among soil layers of different soil types.The coefficient of variation of soil nitrogen content is negatively correlated with soil depth.The greater the soil depth,the smaller the difference in nitrogen content among soil types.(3)The total carbon density of main forest soil types in Sichuan Province is7.113kg·m^-2-25.203kg·m^-2.The average soil total carbon density was highest in mountain meadow soils,and lowest in high mountain cold desert soils.In all soil types,the total carbon density of each soil layer unit thickness decreases with the increase of soil depth,and the total carbon density of the surface soil is the largest.The total nitrogen density of the main forest soil types in Sichuan Province ranged from 0.614 kg/m² to 1.226 kg/m².The average soil total nitrogen density was highest in mountain meadow soils and lowest in alpine cold desert soils.The total nitrogen density in the thickness of all soil layers in all soil types decreased with the increase of soil depth,and the total nitrogen density in the surface soil was the largest.(4)The total carbon density and total nitrogen density in the main forest soils are roughly as follows:in areas below 2000 m above sea level,they gradually increase with increasing altitude,and in areas with altitudes above 2000 m,with elevation Increase and decrease.The total carbon density of soil decreased with the increase of temperature,and there was a significant negative correlation between the two.With the increase of precipitation,the total carbon density in soil decreases,and there is a significant negative correlation between the two.The total soil nitrogen density decreased with the increase of temperature,and there was a significant negative correlation between the two.With the increase of precipitation,the total nitrogen density in soil decreased,and there was a significant negative correlation between the two.The higher the soil bulk density of the forest,the higher the total carbon density may be.The total carbon density of the main forest soil in Sichuan Province is not highly correlated with soil clay.There was a positive correlation between soil total nitrogen density and total carbon density,and reached a significant level.