A balance adjustment method on grading results of cultivated land quality

In order to evaluate the quality of cultivated land, the grading of cultivated land was carried out in China. Due to the differences of grading indicators and weights in different districts, the grading results at county level are not comparable. In order to make the classification results at the county level more comparable, this paper took Utilization Index (UI) as an example to study. Firstly, correction fitting equation is made based on linear regression equations between standard food production (SFP) and UI of all index areas in a province. Secondly, correction factor for UI of each village of this province is calculated by the correction fitting equation. Finally, the UI of all cultivated patches is adjusted by the correction factor. In addition, the method is experimented on Beijing cultivated land data. The adjusted result showed that the related coefficient between SFP and UI increased from 0.327 to 0.728, and the deviation of sum of squares among groups reduced by 27.9% than before. From these two points, it could be illustrated that comparability of UI among index areas increased greatly after adjustment. Through calculating, it was found that the mean value of UI was 5% less than before, which proved that the method maintained the overall trend of the original achievements when the classification results' comparability is improved.