| Hunan-Jiangxi-Fujian Hilly and Mountains Area is the core region of The Southern Hilly and Mountains Area of China,which is a vast place where owns advantageous geographical condition,abundant of natural resources,and developed economic level,that it plays a decisive role in the ecological environment protection and the construction of social and economic development.But the terrain ups and downs,which make the mountainous hills has poor resistance to soil erosion and soil and water loss happened easily.At the same time,the mountain's excessive developments bring strong human disturbance,which make it become a typical soil ecological fragile region in our country.Woodland has a significant function in improving the ecological environment and conserving soil and water,etc.Soil is an important part of forest ecosystem,and soil nutrient has a decisive influence on forest land productivity,maintaining and improving the soil nutrient status durably is an important factor for the stability and the sustainable development of forest ecosystem.Through setting sample sites and sampling soil sample across the Hunan-Jiangxi-Fujian Hilly and Mountains Area,we got 194 soil samples,the geographic information such as longitude,latitude and elevation,the landscape information such as vegetation type,forest type,vegetation coverage,the human activities information such as fertilization,irrigation,and the field measured pH information of each sampling site were recorded.Combined with the laboratory tests and analysis,soil organic matter(SOM),soil total nitrogen(STN),available potassium(SAK),and available phosphorus(SAP)were measured.And the average precipitation and temperature for years were extracted through the location information of sample sites.Traditional statistics methods and the changed Nemero formula were used in the research of all the study area and the branch study area under the different classification,which got the characteristics of soil nutrient,soil fertility status,soil spatial variability,and the influence of soil nutrient by environmental factor and the main conclusions as follows:(1)The surface soil nutrient content in woodland of the Hunan-Jiangxi-Fujian Hilly and Mountains Area was analyzed based on the basic descriptive statistics,as well as to the proportion of each nutrient level were counted,which concluded that the soil organic matter was at a higher level of our country;the soil was lack of available phosphorus;the soil total nitrogen was slightly better than the overall level of our country;the available potassium was slightly less than the overall level,the soil pH value was clearly lower than the average level of our country,which allover characterized as acidic.(2)Within the application of the changed Nemero formula in soil nutrients of Hunan-Jiangxi-Fujian Hilly and Mountains Area,the single fertility coefficient of the whole study region and the branch study area both showed that:the content of SOM was the highest and the content of SAP was the minimum,the soil pH value was at medium level,and all the comments of soil comprehensive fertility were medium.Under the different mountains,the soil comprehensive fertility present as Jiangxi-Fujian mountain Areas>the western Jiangxi mountain Areas>Hunan-Jiangxi Boundary Mountain Areas.Within the elevation level of hill,Low mountain,mountain,the higher of elevation level,the higher values of the soil comprehensive fertility coefficient and the soil single fertility coefficient of SOM,STN and soil pH value.The soil comprehensive fertility coefficient between different woodland types performance as:shrubs>broad-leaved forest>the mixed forest>Phyllostarchys peteroycla forest>coniferous forest.Comparing the result of natural forests and plantation woodlands,all the soil nutrient indicators of the soil single fertility coefficient of natural forest,without the SAP,and the soil comprehensive fertility coefficient were higher than that of plantation.(3)From the spatial variability of soil nutrients,all the study area and the branch study area of Hunan-Jiangxi-Fujian Hilly and Mountains Area have the highest SAK,mostly showing moderate spatial variability,and have the lowest soil pH value,mostly showing weak spatial variability.Within the elevation level of hill,Low mountain,mountain,the higher of elevation level,the lower soil single fertility coefficient of SOM and soil PH,but the higher soil single fertility coefficient of STN,SAP and soil comprehensive fertility coefficient.According to different classification rules to classify the whole study area,the soil spatial variability of each category was lower than the whole study area,which illustrated the scale dependency of the soil spatial variability.Thus appropriately narrowing the research scale or classifying the sample sites can reduce the analysis results of spatial variability.(4)By combining the comprehensive coefficient of variation and the comprehensive fertility coefficient,we can see that Jiangxi and Fujian mountain areas have lower coefficient of variability of nutrients and the highest comprehensive fertility in different classification of the mountains.Two aspects of advantages in nutrients and nutrient stability comprehensively show that soil fertility status have more advantage in Jiangxi and Fujian mountain areas.In different classification of woodland,Coniferous forest not only have the highest spatial variability but have the lowest comprehensive fertility coefficient,which provide the most disadvantages of the soil fertility conditions;Broad-leaved forest land has the lowest nutrient variability and higher comprehensive fertility coefficient,and have more advantages in soil fertility status.There is a lower soil spatial variability and higher soil comprehensive fertility in the natural forests which compared with plantation,and there are more advantages of soil nutrient status totally,it's potential for them to maintain the state of the soil ability.(5)Through the Classical Statistical Analysis of which soil properties and it's environmental factors passed Kolmogorov-Smimov normality test,we can see that:1)Pearson correlation coefficient detected that SOM,STN and soil pH value were positively related to the elevation,but performance have negative correlation with average temperature.2)After analyzing and classifying by the environmental parameters,including climate,geography and vegetation,the results of ANOVA showed that different levels of environmental factors showed significant regional impacts on soil nutrient content of each attribute factor.3)Stepwise multivariate linear regression analysis showed that:SOM and STN,elevation and average temperature were the decisive environment factors,in which elevation produced positive effect and temperature produced negative effects.While for soil pH value,only average temperature enter into the linear regression model have the qualification to explain the variation proportion of the pH value whose data is 22.90%. |
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