| Soil spatial heterogeneity includes spatial pattern of soil type and spatial variability of soil properties.Soil nutrient availability and spatial heterogeneity of soil is soil ecosystem productivity and biodiversity are key factors.On the basis of field investigation and sampling,comprehensive analysis of natural and human factors,north tropical typical Asian Alpine-south east of Ailao mountain,northeast slope of Wutai mountain(Red River Butterfly Valley)as the research object,the spatial pattern of soil type and the spatial variability of soil physicochemical properties of the mountainous area are the research contents.According to the characteristics of soil formation,we collected a vertical sample,according to the altitude,slope and other topographic features,set up a vertical transect,with a height of 100 m spacing,5 points were randomly selected in the 100 m spacing,and the soil mixing samples were collected from the surface(0~20cm)and the sub-surface(20~40cm).At altitudes below 600 m baseband(North of tropical seasonal rain forest of laterite)range,choose banana,rubber and secondary 3 different types of land,2 and 3 respectively and one sample,according to the different land types,a horizontal sample was set up,and three species of banana,rubber and secondary forest land were selected in the transect,and 30 m × 30 m temporary samples were set for each plot Random sampling of five points to collect mixed samples.Based on the soil types of the study area,1: 50,000 soil types were plotted,and the spatial heterogeneity of soil types was analyzed by using the landscape pattern index such as patch number,frequency index and dominance index.Correlation analysis,principal component Analysis and Nemerow index method were used to analyze the soil physicochemical properties,soil fertility and the relationship between the soil surface and sub surface.The results show:1.The spatial structure of the soil type in the study area is as follows: There are 4 soil classes,7 subclasses,9 soil classes,and 17 subclasses in the study area.The differentiation pattern of soil type space for the three structural forms: vertical zonality,branch combination and terrace type combination.The red soil is dominant soil in the quantitative structure.The dominant index of yellow brown soil was the highest.The minimum area of lime soil is the lowest of the dominance index.The number of new soil patches was the largest,and the spatial distribution was the most dispersed.2.The soil physical properties showed that the soil moisture,sand and sand grains increased linearly with the increase of altitude,and the content of clay increased linearly with the increase of altitude.In the horizontal direction,soil moisture,clay content and The total porosity is secondary forest land>rubber field>banana land.The soil sand content is banana>rubber>secondary forest land,the better the soil development,the better the sand content and the increase of the clay content.Secondary forest land,rubber and banana soil structure is very good,secondary forest soil is the most loose,the best ventilation and permeability,rubber and banana to second place.3.The results of soil chemical properties were as follows: the content of pH in soil was 4.05~6.15,and the content of soil pH and soil available phosphorus decreased linearly with the increase of altitude.The content of organic matter,total nitrogen,available nitrogen,available phosphorus and total potassium increased linearly with the increase of altitude.The change of total phosphorus content was not obvious with altitude.The soil organic matter content of soil pH,total phosphorus and sub surface soil showed the banana land>Rubber land secondary forest land.The organic matter,total nitrogen and total potassium in the soil surface were secondary forest land>banana land>rubber soil.The surface soil available nitrogen and available potassium content showed secondary forest>banana rubber,subsurface soil available nitrogen and available potassium content were rubber and secondary forest>banana banana>secondary forest rubber.From the sampling depth,soil organic matter,total nitrogen,available nitrogen,available phosphorus,total potassium and available phosphorus content than subsurface vertical surface soil pH value is lower than the surface,but different than subsurface land surface soil pH value.Through principal component analysis and correlation analysis,the elevation was associated with a significantly negative,the first principal component reflects the elevation factors on soil moisture,total nitrogen,total phosphorus has a great influence and pH;different types of man-made organic matter,hydrolytic nitrogen,total phosphorus,available phosphorus and potassium content difference.4.The soil fertility is shown as: In the vertical direction,the soil comprehensive fertility coefficient was 1.07~1.64,the total contribution rate of total potassium to soil fertility was the highest,and the comprehensive soil fertility was slightly higher than that in sub-surface.The soil fertility increased linearly with the increase of altitude.The soil fertility The soil bulk density has the highest contribution rate to the soil fertility of rubber and banana,and there are many factors influencing the soil comprehensive fertility of secondary forest land. |
