The Establish Of Research High Precision Nitrogen Partitioning Fertilizer Prescription Map Based On GIS

Through the research of different sampling methods and study the spacing effect onthe partition of soil nutrients in cotton field with drip irrigation of sampling,usingmultivariate statistics,geostatistics and GIS techniques,to determine the reasonablesampling method and the optimum sampling interval nutrient partitioning process in thestudy area. And on this basis,the use of the study area soil nutrient reasonable partitionfuzzy c-mean clustering method,and based on the actual data to verify the partition results,a high precision partition map.Study area to each partition recommended fertilizer as thebasis,the establishment of the regional nitrogen fertilizer prescription mappartition.Through the research and analysis from the following five conclusions:(1)First determines the grid sampling method for the reasonable sampling method inthis study,on the basis of the20m×20m as the optimum sampling interval of the study.Through the comparison of different sampling methods(random sampling method and gridsampling method) of soil nutrient conditions(nitrogen, phosphorus and potassium) analysisof spatial variability and the interpolation accuracy of descriptive statistics,test,resultsshow that the grid sampling method and sampling method are more reasonable;underdifferent using distance on the grid (20m×20m,30m×30m,40m×40m,50m×50m) werecompared and analyzed;through the same method to determine20m×20m samplinginterval generation partition based fertilizer prescription maps for later stage.(2)The sampling spacing is20m×20m of soil three nutrients presented moderatevariability and moderate spatial autocorrelation.Through descriptive statistics analysis,inthe20m×20m sampling interval under the condition of the soil nutrient content were threefor moderate variability,and in accordance with the normal distribution.The nugget effectthree kinds of soil nutrients in between25%-75%,the area of the three soil nutrients hadmoderate spatial autocorrelation;The spatial variability characteristics mainly by structuralfactors and random factors common cause with.The relevant variable range are larger thansoil sampling interval,so it could be that in the study area based on20mgrid samplinginterval sampling of soil is reasonable.(3)From the spatial distribution of soil nutrients map making,can reflect thedistribution of soil nutrient visibility.20m×20m Kriging sampling interpolation resultsinterval graph than the other three kinds of patterns of nutrient distribution distance themost subtle reaction,the spatial distribution of soil nutrients in the performance of spot orpatch level is obvious,interpolation precision is high;The spatial distribution of soilnutrients in the overall pattern of the generated on both overall and local nutrientdistribution trend.Is mainly due to the formation of the sample point spacing is smaller anduniform distribution.In the polished surface slightly rough interpolation.(4)The research area of the optimal partition number is3.Selecting optimum samplinginterval of20m×20m three kinds of soil nutrients (nitrogen, available phosphorus,available potassium) data as the data source for the principal component analysis, using thefuzzy c-mean clustering method, and based on the fuzzy performance index (FPI) and normalized classification entropy (NCE)minimum is divided the study area into3precisenutrient partitioning. The fuzzy weighted index is1.7, index of the chaos research area in0.23, partition overlapping degree is relatively small, the partition affiliation obviously.According to the division of regional soil total nitrogen content, partition two in the soilnitrogen content is lowest; partition three. The soil nitrogen content is the highest; betweenthe partition between the two.(5)According to the nitrogen content of three partitions,combining the target yieldmethod calculation:partition two in the soil nitrogen content the lowest (about0.3g/kg),therequired amount of nitrogen fertilizer up to330kg/hm2;Three partition of soil nitrogencontent is the highest (about0.5g/kg),the nitrogen fertilizer application at least,for205kg/hm2;Between the partition between the two,nitrogen fertilizer application amountwas253kg/hm2.thereby generating nitrogen fertilizer prescription map partition.