Spatial variability of nutrients in newly cultivated soil of Xiaojingzi Farm

Spatial variability of nutrients in new cultivated soil was studied by geostatistical and traditional statistics analysis,in order to obtain scientific basis of demonstrating soil nutrients management and balancing fertilization technology for new cultivated soil of Xiaojingzi Farm.The system evaluation result of soil nutrients showed that soil available P is badly deficit,NH4+-N is deficit,available K sporadically deficit and the content of available Ca,Mg and S are abundant,and especially the content of available Ca is quite high.Statistical analysis result of soil nutrients showed variation coefficients of soil OM,NH4+-N,available P,K,Ca,Mg and S range from 36.0% to 164.6%.Variation of soil OM and available P is comparatively high,variation coefficients is 87.8% and 164.6% respectively;variation of soil NH4+-N and available K is high,variation coefficients is 52.7% and 53.4% respectively;variation of soil available Ca,Mg and S is relatively low,variation coefficients is 36.0%,37.6% and 46.5% respectively.Result of semi-variance analysis with geostatistics showed that spatial variation relativity of soil nutrients presented rather great differentiation.Nugget/sill of soil available P,K,Mg and S range from 25% to 75%,and present moderate spatial dependence;and nugget/sill of soil OM,Ca and NH4+-N are more than 75%,and present weak spatial dependence.Isoline maps of soil nutrients are made by the best Kriging interpolated according to result of semi-variance analysis.Isoline maps of soil nutrients indicated that spatial distribution variation of OM,available P and K was less,and distribution is relatively in equality;that of NH4+-N present strong,and Ca,Mg and S present moderate variation. Variation of NH4+-N mainly caused by fertilization and cultivation,variation of available Ca,Mg,S,OM and K mainly caused by soil tiny variation and soil texture,terrain and agrotype and cultivation and irrigation,variation of available P mainly caused by soil character and soil texture,terrain and agrotype.