Construction of cultivated land quality evaluation system in provincial level based on multilevel indicators

Abstract: A reasonable cultivated land quality evaluation system reflects the spatial difference of cultivated land quality betterand benefits the protection and management of cultivated land. This paper aims to build a more convenient evaluation system of cultivated land quality for acquisition of the quality distribution of cultivated land in provincial level. The system of agricultural land gradation is widely used for evaluation of cultivated land quality in China. But its poor index comparison and shortage of engineering factors are disadvantages for current management of cultivated land resources. Therefore, based on the existing idea and method of agricultural land gradation, this study suggested an improved evaluation system called the hierarchical control method and took NeiqiuCounty, Hebei Province as a case study.This paper attempted to establish an evaluation system byconsidering cropping system as control factor to characterize the climate effects,land conditions and engineering conditions as the evaluation positive factors, and limiting conditions as the evaluation negative factors. Based on the evaluation system, this paper built three-dimensional Rubik's cube model for querying results. Then, this paper evaluated the quality of cultivated land in Neiqiu based on the hierarchical control method. The quality of cultivated land in Neiqiu was divided into 5 grades and the areas of Grade 1, 2, 3, 4, and 5 were 9 681.30, 11 708.28, 6 739.46, 2 112.59, and 123.55 hm2, respectively, accounting for 31.88%, 38.56%, 22.19%, 6.96%, and 0.41% of the total cultivated land area, respectively. For proving the rationality of the evaluation results of hierarchical control method, this paper compared the results differences betweenhierarchical control method and factor method onagricultural land quality. The study shows that: 1) Compared with the traditional evaluation system, the system of hierarchical control method has not only the large spatial scale control by cropping system, but also the fine spatial scale evaluation factors. Meanwhile, the considered factors are uniform so it is comparable in provincial scale. Hierarchical setting of evaluation system is convenient to operate. Also, the three-dimensional Rubik's cube model is easy to inquire the grade of cultivated land quality. 2) Compared to the system of agricultural land gradation, the hierarchical control method considers and highlights the influence of engineering factors (guaranteed rate of irrigation,drainage condition, infrastructure area percentage, and road accessibility) on the quality of cultivated land. Meanwhile, the percentage of cultivated land area at each grade is symmetrical in the matrix form. The grade of cultivated land is mainly distributed on the axis of symmetry. Compared with the factor method, it is found that the trend of the area distribution of cultivated land for the 2 methods is similar in town level, but the area proportion is different. 3) The differences of the influence degree of different factors on the quality of cultivated land need to be further studied. The results can provide some basis for land consolidation, cultivated land requisition-compensation balance, basic farmland protection and other relevant land management work.