| Soil,as the most basic carrier of terrestrial ecosystem,can provide all kinds of nutrient elements for plant growth,among which soil carbon,nitrogen and phosphorus are the focus of global element cycle and the core of exploring soil ecological stoichiometric characteristics,which is an important basis for effectively characterization of soil health status and ecological quality.Anxin County,as an important ecological functional area in Xiong'an New District,has attracted much attention.Understanding the spatial distribution of soil carbon,nitrogen and phosphorus,as well as the circulation and balance mechanism,can provide basic data support for the ecological construction and ecological restoration of Anxin County,and has important practical significance for the rational planning and utilization of regional land..In this paper,the soil of Anxin County was taken as the research object,and 142 soil sampling points were determined by grid distribution method.Combined with the principle of geostatistics and GIS technology,the spatial distribution of soil organic carbon(SOC),total nitrogen(TN),total phosphorus(TP)and ecological stoichiometry(C/N,C/P,N/P)in Anxin County was explored.Five utilization modes of bare land,paddy field,irrigated land,forest land and reed land were selected to explore the characteristics of soil carbon,nitrogen,phosphorus and ecological stoichiometric under different utilization modes.The main research results were as follows:(1)The surface soil of Anxin County(0?20cm)had moderate variation in carbon,nitrogen,phosphorus and ecological stoichiometric.The average contents of soil SOC,TN and TP were 13.13 g/kg,1.39 g/kg and 1.10 g/kg,respectively.According to the National Second Soil Census nutrient grading standard,the SOC and TN in the study area were in the middle level of grade 3,and the level of TP was in the level of grade 1.The mean values of Soil C/N,C/P and N/P were 9.62,11.94 and 1.26,respectively.SOC,TP,C/P and N/P showed a small and strong spatial autocorrelation,soil TN showed a large and moderate spatial autocorrelation,and C/N showed a large and weak spatial autocorrelation.(2)SOC,TN,C/P and N/P in Anxin County show consistent spatial distribution characteristics,with higher spatial distribution in the west and east and lower spatial distribution in the middle.The distribution of TP in soil is patchy.The spatial distribution of soil C/N is higher in the north and south,and lower in the middle.(3)The soil SOC and TN contents of the five land use modes showed obvious"surface aggregation",and decreased gradually with the increase of soil depth in vertical direction.The mean values of SOC and TN in 0?100 cm soil were reed land>forest land>paddy field>irrigated land>bare land.There was no significant change of soil TP with the depth of soil layer,and soil TP content in 0?20 cm soil layer was significantly higher than that in other utilization modes.The difference of soil SOC and TN reserves of different utilization modes is mainly concentrated in 0?40 cm soil layer,and the reserves of C and N are reed land>forest land>paddy field>irrigated land>bare land,which indicated that the ability of fixing C and storing N was better in reed land and forest land with less human disturbance and vigorous vegetation growth,and there was almost no difference in TP reserves between different utilization modes in the same soil layer.(4)There were significant differences in soil C/N,C/P and N/P among the five land use modes,among which bare soil C/N,C/P and N/P all showed the smallest performance.The soil C/N of five different land use modes had no obvious change in the vertical direction.In the soil layer of 0?60 cm,the C/N of paddy field or irrigated soil was the largest,and in the soil layer of 60?100 cm,the C/N of forest land was the largest.The average C/N of forest land>paddy field>irrigated land>reed land>bare land.C/P and N/P decreased with the increase of soil depth.The mean values of C/P and N/P were reed land>forest land>irrigated land>paddy field>bare land,and forest land and reed land were higher among different soil layers.(5)Soil types and soil attribute factors had a certain impact on soil carbon,nitrogen and phosphorus ecological stoichiometry in Anxin County.There were some differences in the mean values of SOC,TN,TP,C/N,C/P and N/P values of meadow-cinnamon soil subclasses were the smallest,and there were statistical differences between them and the other four soil subtypes.There was no significant difference between other types of soil carbon,nitrogen,phosphorus and ecological stoichiometry(p<0.05).Through canonical correlation analysis,it was found that SOC,TN,C/P and N/P of soil had a great cumulative relationship with bulk density and pH value in soil factors.By exploring the spatial distribution characteristics of soil carbon,nitrogen,phosphorus and ecological stoichiometry in Anxin County and the differences among different land use modes,it is revealed that the content of SOC and TN in soil in Anxin County remains to be improved,and the content of TP is very rich.The soil ecological stoichiometric in the research area are mainly restricted by nitrogen,so it is necessary to pay attention to the intensity of straw returning to the field in agricultural production,strengthen the improvement and utilization of bare land,further expand the conversion of farmland to forest and lake,so as to make the land play a greater ecological effect. |
PDF Full Text Request