Time sequence division of high-standard prime farmland construction area

Abstract: The construction of high-standard prime farmland is an important measure to protect the cultivated land and ensure the food safety in China. Researchers have gained abundant achievements in this field, however, the previous methods may not be appropriate to analyze the construction of high-standard prime farmland in the alluvial plain of Yellow River. Firstly, the indices were redundant and it was difficult to determine the weights because the cultivated land in the alluvial plain of Yellow River had the overall flat terrain and got the similar natural quality. Secondly, the existing Classification and grading of cultivated land natural quality was not accurate due to the evaluation system and the method. Thirdly, it's difficult to choose appropriate evaluation units, and the existing evaluation units such as administrative villages, land use patches and grid cells had different applicable conditions. This paper took Shanghe County, Shandong Province as the research area, and the detailed research process could be described as follows: 1) We constructed the cultivated land quality evaluation system, including the natural quality, the space form and the infrastructure of the land; 2) We defined the evaluation units (1′×1′, a total of 487 units) by the longitude and latitude grid, and calculated the values of units and graded the indices according to equally spaced reference; 3) We determined the weights by the entropy weight method, and evaluated the comprehensive quality of cultivated land; 4) We graded the time sequence of the high-standard prime farmland construction and allocated the scores to the land pattern spots. Results showed that the suitable construction area with the time sequence of the first, the second, the third and the fourth level accounted for 7.83%, 69.10%, 22.93% and 0.14% respectively, in which the construction areas with the time sequence of the first and second level were mainly distributed in the north and west, while the third and fourth level mainly in the south. However, according to the Classification and grading of cultivated land natural quality, the land with the natural quality of Grade 5 accounted for 13.34% of total area and was mainly distributed in the south, the land of Grade 6 accounted for 76.27% and was mainly distributed in the central part, and the land of Grade 7 and 8 accounted for 10.40% and was mainly distributed in the south. There were distinct differences between the two results, which indicated that the method and the evaluation system in this paper could significantly improve the evaluation accuracy. We can draw the conclusion that when there is no significant difference for the overall natural qualities of cultivated land, the division result would be completely different if we take into account the high-standard prime farmland construction standard that it should be appropriate with the modern agricultural production and operation modes, which also indicates the necessity to land's scale management in the modernized agriculture of China. This research provides a new idea for the region division of high-standard prime farmland construction's time sequence, as well as offered a reference for the construction of high-standard prime farmland in alluvial plain of Yellow River.