Evaluation of potential of unused land exploitation in Northern Tianshan Mountain Economic Belt — A case study of Fukang City

Xinjiang region has relatively abundant unused land resources that can be rationally developed and used. This is beneficial to ease the increasingly worsening conflict between people and land and ensure regional food security to a certain extent. This paper chose Fukang City in Northern Tianshan Mountain Economic Belt as the research area and used twelve factors to build up an evaluation index system for Fukang City. The twelve factors included soil salinity, soil depth, soil texture, organic matter content, landform, forest cover rate, irrigation rate, soil erosion module, cumulative temperature ≥10 ℃, distance from stream, runoff volume of watershed and annual precipitation. The ecological niche model was used to evaluate the suitability of unused lands converted into arable lands in the study area. The results showed that unused lands (including highly suitable and basically suitable) most suitable for conversion into arable lands accounted for 22.21% of total unused lands in the region. Such lands located in the lower part of piedmont alluvial fans and in relatively flat terrains. Reluctantly suitable unused lands only accounted for 16.36% of total unused lands and were mainly located at the edge of the northern desert and in the upper parts of southern piedmont alluvial fans. Unused lands unsuitable for development accounted for 61.43% and mainly distributed in the southern slopes, the edge of piedmont alluvial fans and the fringe zone close to the northern desert. On the basis of the evaluation results, the paper chose potential index, potential increase in arable land, unused land area in town and sub-town, unused arable land development area, unused arable land proportion, average patch area and patch fragmentation index to build a development potential matrix of unused lands in the study area. Cluster analysis was also used to regionalize unused lands. Based on the research, the study area was divided into five potential zones. Grade I potential zone covered an area of 21 000.97 hm^-2 with potential additional arable land area of 15 222.92 hm^-2. Grade II potential zone was 12 875.69 hm^-2 with potential additional arable land of 10 155.41 hm^-2. Grade III potential zone was 5 008.84 hm^-2 with potential additional arable land of 4 165.35 hm^-2. Also grade IV potential zone was 878.67 hm^-2 with potential additional arable land of 753.78 hm^-2. Then grade V potential zone of unused lands was unsuitable for exploitation. The regionalization of the unused lands provided the theoretical basis for the development and utilization of unused lands in Fukang City both in time and space scales. It also had some practical significance in terms of future pattern of differential development and utilization of unused lands.