| The black soil area,as the main production area of commodity grain in China,grasping the quality of its cultivated land is of great significance for rational utilization and protection of cultivated land resources.Heilongjiang Province used the current maximum yield of county crops to calculate the yield ratio coefficient and rank the natural quality of cultivated land.There is a problem that the dry land grade is higher than the paddy field grade.In response to this unreasonable phenomenon,the impact of the output ratio under different calculation methods on the grading results is studied to rationalize their grading.This thesis selects three typical county in cold black soil areas,which are Fujin City in the northeast of Heilongjiang Province,Wuchang City in the south and Helen City in the middle as the research areas for empirical study.Utilize the adjusted yield ratio to grade the cultivated land quality,and compare their distribution results.The results of the study found that: Using the highest yield of crops in the secondary zone to calculate the yield ratio,the natural quality of paddy fields has not changed,the natural quality of dry land in Fujin City and Wuchang City has decreased 1grade,and the natural quality of dry land in Helen City has been improved 1 grade,there will still be a problem that the dry grade is higher than the paddy field land grade;Using the crop production potential index to calculate the yield ratio coefficient,compared with the original grading results,the natural quality grade of dry land in Fujin City is reduced by 1 to 3 grade,the natural quality grade of dry land in Wuchang City has been improved 1 grade,the natural quality grade of dry land in Helen City has risen and fallen,the paddy field grade has not changed,and the grading results are not in line with the actual situation;It is used as a nutrient equivalent to correct production the ratio coefficient,compared with the original score,the natural quality of the paddy field does not change,and the decrease of the dry land grade is between 1 and 3,and finally no phenomenon of dry land grade higher than paddy field grade.It is also in line with the actual situation.This thesis supports the revision of the “Regulation for Gradetion on Agricultural Land Quality”(GB/T 28407-2012)and the third national land survey cultivated land grading survey evaluation work through the study of three typical county cases,and provides a reference for improving the national comparability of cultivated land grading results,and it has a positive reference value for the new round of cultivated land grading work in Heilongjiang Province and the entire black soil area. |
