Evaluation on reclamation potential of unused land of the Yellow river delta based on ecological security

Abstract: In China, to achieve the goal of "dynamic balance of total cultivated land", it is important to develop and utilize the unused land resource to make up the loss of cultivated land. Before the development of unused land, we should first conduct the suitability evaluation for unused land. However, many attentions have been called on the natural suitability evaluation, while few attentions have been paid on ecological factors and economic factors for a long time. This paper made in-depth analysis of various factors affecting the development and utilization of unused land in the study area, and established a land suitability evaluation index system, which includes 19 indices selected from natural suitability, ecological safety, and economic feasibility. Based on the spatial database of land use, spatial analysis methods in Geographic Information Systems (GIS) are used to evaluate and statistically analyze each spatial layer and to explore the spatial pattern of the unused land development under different conditions. This study found: The total unused land in Dongying city covers an area of 271,400 ha, according to the statistics provided by land use updated survey in 2010. Due to constrained by ecological factors, the area which can be developed and utilized is 77,200 ha, accounting for 28.44% of the total unused land. Considering economic feasibility, the developable area reduces to 36,700 ha, accounting for 13.72% of the unused land. It can be seen that the developable land decreases sharply when ecological and economic factors are considered, only accounting for over 13% of the total unused land. Especially, ecological factors may play a major role in restricting the development of unused land. The unused land can be developed for many purposes of use, especially for ecological use. The ecological value of developing unused land includes maintaining biological diversity and regional ecological balance. The proposed index system in the paper has incorporated the factors from natural suitability, ecology and economics, which is advantageous over traditional appraisal method. The new method improves the suitability evaluation of unused land. Our evaluation results in Dongying are suitable with the status of land use and are meaningful for unused land development and consolidation planning.