| The spatial heterogeneity of soil nutrients,spatial distribution and influencing factors of soil organic carbonand Castanopsis kawakamii growth suitability were studied in this paper．Geostatistics method combined withGIS technical was applied to study the spatial heterogeneity of soil nutrients,including pH,total nitrogen(TN),total phosphorous(TP),total potassium(TK),hydrolyzable nitrogen(AN),ammonia nitrogen(ANN),availablephosphorous(AP)and available potassium(AK)in C.kawakamii natural forest of Sanming City,FujianProvince．The results showed that pH has a weak variation,other items exhibited medium spatial variability,thedescending order of the variation intensity is ANN(67.75%),AP(43.54%),AK(32.84%),AN(31.03%),TN(29.41%),TK(25.25%),TP(22.14%),pH(3.39%)．Parameters of theoretical variogram models for soilnutrients showed that in the perspective of entire profile,pH,TK,AP fitted exponential mode,TN fitted Gaussianmode,TP,AN,ANN can be best described by spherical mode and AK was well fitted by linear model．Theeffective range of pH,AK,TK were267m,549m,and1806m respectively,while the values for TN,TP,AN,ANN,AP were130m,120m,182m,108m and117m respectively．In terms of spatial structure,pH,TN,TP,AN,ANN,AP showed high spatial autocorrelation,and their spatial heterogeneity was greatly affectedby soil structural factors．TK indicates moderate spatial autocorrelation,which was affected by soil structuralfactors and random factors．AK exhibited weak spatial autocorrelation,and its spatial heterogeneity was primarilyaffected by random factors．The standardized semivariograms values of pH,TN,AN,ANN,TP,AP,TK wereall fluctuate around1in different direction respectively,which can be approximated that they were anisotropic,whie AK showed isotropic．The fractal dimension of eight soil indicators were difference in Ⅰ~Ⅲsoillayers．Moran I coefficients indicated that different soil indicators were all emerged remarkable positive spatialcorrelation or negative spatial correlation in the effective range(0~200m),in other cases they appeared notrelevant in spatial distribution．The spatial distribution of soil nutrients have different characteristics,TN insouthwest and northeast both have a high value area,along with the direction of WN-ES,It emerged stripedistribution,regularly decreasing from WS-EN line to northwest and southeast respectively．TP content increasedfrom south to north first and then reduction．TK emerged circle distribution,and was low in central area,high inmarginal area．pH appeared a shape of stripe combined with patchy,regularly decreased from northeast tosouthwest．AN decreased from northeast to southwest．ANN,AP both increased from southeast to northwest．AKregularly distributed in study area and have high value areas in northwest and southeast,from southwest tonortheast AK content increased first and then decreased．all these results may be available for improving thesampling design of soil nutrients and for interpolation and map of soil nutrients,it's also important to sustainableuse of soil and the regeneration and recovery of C.kawakamii natural forest．GIS technology was applied to study the spatial distribution and influencing factors of soil organic carbon inthe mid-subtropical C.kawakamii natural forest of Sanming City,Fujian Province．The results showed that thevariation of organic carbon conten(tO),density and reserve of soil all are moderate．The value of organic carboncontent,density and reserve were all descended with the increase of soil depth and mostly aggregating in layerⅠ(0~20cm)．The soil organic carbon content in layer Ⅰw as32.15g/kg,2.35and4.63times than the layer Ⅱ(20~40cm)and layer Ⅲ(40~60cm)respectively,and the entire profile was17.60g/kg．The soil organic carbon density layerⅠ~Ⅲ were6.76kg/m~2,3.17kg/m~2and1.74kg/m~2respectively,the average soil organic carbondensity was11.67kg/m~2．Soil organic carbon reserve in C.kawakamii National Forest Park stored at0~60cmwas about1.49×10~4t,layerⅠ,Ⅱ, Ⅲ were8.66×10~3t,4.01×10~3t,2.20×10~3t respectively,which werecalculated with voronoi．ANOVA and LSD test showed that the values of soil organic carbon content,density andreserve in different layers were all reached a significant level, F value were483.75,309.23,31.93respectively．Soil organic carbon content and density have similar spatial distribution in southwest and northeast,which both have a high value area,along with the direction of WN-ES．They emerged stripe distribution,regularlydecreasing from WS-EN line to northwest and southeast respectively．The results of correlation analysis andstepwise regression analysis showed that soil organic carbon content associated with soil physicochemistryproperties,reaching a significant level,and were positively correlated with TN(0.82),TP(0.67),AN(0.76),AP(0.31),AK(0.58),negatively correlated with the pH(-0.58),TK (-0.20)and soil bulk density(B,-0.48),and can be further described by the formula：O=27.77+37.88TN+0.05AN+59.69TP-7.28pH-7.04B．The effects of topography,soil physicochemistry properties and human disturbance on soil organic carbon inC.kawakamii forest were also analyzed．All these results may be available for enhancing the precision of soilorganic carbon reserve,assessing eco-efficiency of the C.kawakamii natural forest and its roles and functions inregional carbon cycle．Based on the results of soil spatial heterogeneity and soil organic carbon spatial distribution and influencingfactors of C.kawakamii natural forest,C.kawakamii growth suitability evaluation also was studied in thispaper．Delphi was applied to establish the evaluation index system,AHP was used to determine evaluation indexweight and weighted index summation method was used to gain the comprehensive evaluation map forC.Kawakamii growth suitability．The results showed that the percentage of the not suitable,reluctantly suitable,general suitable,moderately suitable and highly suitable area were25.39%,28.28%,18.28%,18.14%and9.92%respectively．Ecological environment is frigle in not suitable area,so it should strictly control adverse land-usechange and the number of tourists,while it also should increase the ecological compensation to localresidents．The reluctantly suitable area can apply appropriate human disturbance measures to enhance thecompetitive strength of C.Kawakamii seeding．To promote C.Kawakamii seedings regeneration and development,in general suitable,moderately suitable area,we can consider the application of organic phosphorous and nitrogenfertilizer．C.Kawakamii growth highly suitable area exist a certain number of gap,so it's necessary to further studyits forest gap dynamics and recovery．These results can be applied to direct C.Kawakamii plantation managementpractices,and it is also useful for overall planning of natural reserve,Eco Fujian,the construction of digital forestand tourism development．... |
PDF Full Text Request