The Applied Research Of Different Methods In The Natural Productivity Evaluation Of Cultivated Land In Jiangxi Province

Natural productivity evaluation of cultivated land can effectively control soil fertility status、nutrient status、soil constraints of cultivated land,etc,it is great significance to guide agricultural production and scientific fertilization.My couny basically completed Evaluation of land productivity at county level in 2012 and started the provincial integration of natural productivity evaluation of cultivated land in 2013.Provincial integration of natural productivity evaluation of cultivated land is mainly to provide the basis for provincial decisions and it is to promote the achievement of evaluation for service of agricultural production on a larger scale.It is still in continuous improvement about ideas and methods of the Provincial integration of natural productivity evaluation of cultivated land in Jiang Xi Province,and there may be some deficiencies in practice.So this paper attempts adopt The evaluation method of diagram spot integration and The evaluation results of samples interpolation method to make farmland productivity evaluation,and comparative analysis and comprehensive evaluation method and the evaluation results. In this paper,it is a case study of Jiang Xi Province to empirical research, At the same time improve the accuracy of the evaluation results,to explore the feasibility and practicality of The evaluation method of diagram spot integration and The evaluation results of samples interpolation method,Further comparative analysis of the advantages and disadvantages or the scope of these three evaluation methods,etc.To provide a reference for the improvement of farmland productivity evaluation methodology, While seeking the methods of suitable for natural productivity evaluation of cultivated land in Jiang Xi Province and to do well.The main conclusions from this article as follows:(1) This article used Delphi and AHP built the farmland productivity evaluation system mainly from four aspects: site condition、profile situation、topsoil situation、soil management and it selected the 13 evaluation factors and determine the weights.(2) This article make full use of the Arcgis techniques and mathematical statistical methods have selected 16582 samples and it screened from numerous soil samples from the province’s county soil samples.And based on the extensive collection and supplementary data,established farmland productivity evaluation underlying database of Jiangxi Province.(3)According to the provincial level standard of cultivated land productivity grade divided into seven grades.The area distribution of the overall of cultivated land productivity grade based on comprehensive evaluation method was normal distribution as the area of the fifth grade maximum,the area was 648,235.32 hectares and it accounting for 21.01% of the total area of cultivated land,The minimum was the seventh grade was 216391.07 hectares and it accounting for 7.01% of the total area, the first grade to the third grade is high yielding land,the percentage was 38.95%, the percentage of the fourth grade to the seventh grade was 61.05%, The evaluation results are consistent with the actual overall of cultivated land fertility status of Jiangxi Province.The area distribution of cultivated land productivity grade based on evaluation method of diagram spot integration was mainly in the fourth grade to the seventh grade, the maximum was the seventh grade and the area and percentage was 937203.81 hectares, 30.38%, the area and percentage of the fourth grade to the sixth grade were 671002.55 hectares, 21.75%,445224.30 hectares, 14.43%,and 631847.84 hectares, 20.48%,but percentage of the area of the first grade to the third grade was 12.96%. Overall evaluation results show great deviation with actual of Jiangxi Province and analysis the reason.The area distribution of cultivated land productivity grade based on the evaluation results of samples interpolation method was mainly in the third grade to the fifth grade, The proportion reached 83.51%,and the area and percentage of the third grade to the fifth grade were 749004.91 hectares,24.28%,1166181.36 hectares, 37.80%,and 661117.07 hectares, 21.43%, the minimum was the first grade and it was 0.02%, The rest of the second grade, the sixth grade and the seventh grade,there proportion is less than 10% and percentage of them were 6.36%,8.32%,1.79%. The evaluation results was better,but there is a certain bias between with the result of comprehensive evaluation method and analysis the reason.(4)By field survey and verification analysis,the grades situation of random verification samples with the evaluation results of comprehensive evaluation method, evaluation method of diagram spot integration and the evaluation results of samples interpolation method of consistent rate of 83.05%, 68.64% and 78.81%,whole show the test effects was good,and evaluation results of the three methods are fully true and scientifically valid.And also shows comprehensive evaluation method better than the other two methods,and through detailed discussion and comparative analysis also shows comprehensive evaluation method more consistent with actual and suit to natural productivity evaluation of cultivated land of Jiangxi Province.(5) Through comparative analysis found that the most simple is a comprehensive evaluation method, Although the amount of data and workload but easy to get and operate,and the downside is that the interfere is big about subjective factors. When the smaller the scope of the evaluation, the higher the precision,on the contrary,need to pay attention to more precision issues about attribute data and graphics;evaluation method of diagram spot integration is the largest on the amount of data and workload,and there were high technical requirements and bottleneck of certain aspects, Due to the impact scale,the accuracy of the results of the county and polygons summary technical routes and methods and other factors,it greatly reduces the precision of the evaluation results, the method is applicable to provincial integration of agricultural land classification achievements;but the evaluation results of samples interpolation method is also larger on the amount of data and workload, however, the method is simple and not very high on technical requirements,but the accuracy depends on the interpolation methods,so the method is applicable to Large-scale regional evaluation,such as regional summary evaluation.(6) This article through comparative analysis of three evaluation methods and evaluation results, At the same time improve the accuracy of the evaluation results, Proved the feasibility and practicality of the evaluation method of diagram spot integration and the evaluation results of samples interpolation method. At the same time, this article carried out a detailed analysis about deficiencies and problems,and this article expounded future research priorities, direction and outlook.