Research On Nutrient Characteristics Of Main Soil Types In The Alpine/Alpine Areas Of Western Sichuan

This study investigated 6 main soil types include subalpine meadow,meadow soil,dark brown soil,brown soil,yellow brown soil and cinnamon soil of sub-alpine/alpine ecosystem in western Sichuan were chosen as research object.In the past ten years,with continued development of Natural Forest Protection and Conversion of Cropland to Forest engineering,the existing natural secondary forest be strictly protected,natural secondary forest continue to recover,quantitative understanding and evaluat the status of nutrient resources and utilization status main in western Sichuan Province.First,the quantitative characteristics,evolution and spatial distribution pattern of organic carbon,nitrogen and phosphorus contents and their ecological and chemical metering characteristics were discussed.The availability of soil nutrient and the trend of soil quality were revealed.The Comparison Study of the Soil Survey results in 1985 and this study,quantitative understanding of the restoration of main soil resources in the mountainous and alpine mountains in northwestern China since 1985.Secondly,through analyzing the characteristics of main soil ion exchange,acidity and alkalinity,the characteristics of soluble salt,and the response of soil ion to soil nutrient was revealed.This study provides the basic data for the construction of relatively perfect data sets of main soil types in sub-alpine/alpine areas of western Sichuan,which is of great significance for the restoration and reconstruction of natural forests and degraded ecosystems in this area.The main developments and conclusions are as follows:1,soil nutrients due to the ecosystem type,vegetation type,land use,soil texture and other environmental factors,with spatial and temporal heterogeneity.The average contents of SOC and TN were as follows:subalpine meadow soil>meadow soil>dark brown soil>cinnamon soil>yellow brown soil>brown soil,soil TP content average performance:subalpine meadow soil>brown soil>The soil SOM accumulation in the whole study area was at a very abundant level,TN was at a rich level and TP was a lack of level,according to the second national soil grading standard.Compared with the results of "Sichuan soil" in 1985,the SOC content of subalpine meadow soil,meadow soil,yellow brown soil and cinnamon soil increased with the increase of the results of the survey.In the dark brown soil and brown soil,The average value of TN in dark brown soil,subalpine meadow soil,cinnamon soil,meadow soil and yellow brown soil was not significantly higher than that in 1985,and TP was lower than that in 1985 The average value of the method decreased compared with that in 1985,and the variation range was between 56.41%and 87.85%.2,soil carbon,nitrogen,phosphorus element spatial distribution characteristics.Vertical soil distribution:0-100 cm soil layer,dark brown soil,subalpine meadow soil,cinnamon soil,yellow brown soil,brown soil SOC,TN,TP basic performance with the soil deepening decline,meadow Soil SOC,TN and TP with the soil depth change is not obvious.Horizontal spatial distribution:Soil SOC,TN and TP are high in central and lower in north and south.Carbon storage:six kinds of soil types of carbon storage range of 27.15-88.63 t/hm2,soil nitrogen reserves range of only 2.23-4.38 t/hm2.3,soil carbon,nitrogen,phosphorus ecological chemical metrological characteristics have a good indicator,can reflect the growth status of vegetation,indicating a limiting role in the nutritional elements.The mean values of soil C/N,C/P,N/P are:meadow soil>cinnamon soil>yellow brown soil>subalpine meadow soil>dark brown soil>brown soil.The soil TP was the main limiting factor in the subalpine meadow soil,yellow brown soil,meadow soil,cinnamon soil,dark brown soil and brown soil.The soil TP was the main limiting factor in the whole study area.4,soil ion characteristics can reflect the soil fertility process.The CEC,salt saturation,pH value,salt saturation and conductivity of different soil types were not obvious.In the vertical spatial distribution,soil CEC showed decreased with the increase of soil depth.PH value,salt saturation the increase of the conductivity and the soil depth with the soil layer is not obvious.