1. Sources of urban–rural construction land transformation

A land use transfer matrix can show the transformation law of urban–rural construction land. As shown in Figure 3, the sources of urban–rural construction land in Qixingguan District greatly increased from 2009 to 2020, with the newly increased area being the most significant when comparing rural residential land, urban land, and transportation land. During that period, 89.36% of the newly increased area of urban–rural construction land came from three areas: urban, industrial, and mining land. The size of the newly added area encompassing scenic spots and special land is small. It was found that most of the newly increased urban–rural construction land (more than 89%) consists of agricultural land types, including arable land and forest land, with proportions larger than 57.72% and not less than 18.92%, respectively. Among the newly increased area of urban–rural construction land, 42.25% is rural residential land, mostly cultivated land (71.54%), and forest land (26%). A total of 94.43% of newly increased urban land consists of agricultural land types, including cultivated land (75.51%) and forest land (18.92%). The areas of newly increased urban industrial and mining land, transportation land, scenic spots, and special land differ slightly, with areas of 1240.65, 3127.94, and 89.65 hm2, accounting for 64.91, 60.3, and 57.72%, respectively. During the study period, the proportions of grassland, gardens, water, and other areas occupied by various types of urban–rural construction land were small. Garden land had the largest area occupied by urban land (72.82 hm2). This was mainly due to the large proportion of agricultural land in Qixingguan District (agricultural land accounted for more than 88.22% of the total area and cultivated land was approximately 44.46% during the monitoring period) and its wide distribution. It is inevitable that it will be occupied to a large extent during the rapid development of urbanization and industrialization.

2. Trend of urban–rural construction land trans formation

With regard to the direction of the reduction in urban–rural construction land in Qixingguan District during the monitoring period, as shown in Figure 4, in terms of absolute quantity, the main reason for the reduction in land from 2009 to 2020 was the reclamation of rural residential land. This represented an area of 5828.00 hm2, accounting for 88.46% of the reduced urban–rural construction land area. A total of 92.19% of the transferred rural residential land was reclaimed as farmland and woodland, which accounted for 57.86% of the total. The second largest proportion was urban land, which had a reduced area of 544.80 hm2, accounting for 8.27% of the reduced area of urban–rural construction land. This reduction was mainly due to conversion to arable land and forest land (together accounting for 82.17%). The reduction in area of urban industrial and mining land, scenic spots, and special land were relatively small: 141.73 and 71.84 hm2, respectively. A total of 3.3% of the transferred urban industrial and mining land was reclaimed as arable land, and more than 52.67% was reclaimed as forest land and other nonarable agricultural land types. However, the transformation of transportation land showed a trend of continuous increase and did not decrease during the monitoring period. During the study period, transportation land only decreased by 1.90 hm2, which again confirmed the remarkable results of road construction in Qixingguan District during the study period, changing it into an important land transportation hub from a regressive area in southwest China. In terms of absolute area, land converted from urban–rural construction land to grassland, garden, water, and other land types was far smaller than the land converted to cultivated land and woodland, which in recent years has been closely related to the many land consolidation works aimed at replenishing cultivated land.

**Figure 3.** New sources of urban–rural construction land in Qixingguan District from 2009 to 2020 (hm2, %).

**Figure 4.** End points for the reduction in urban–rural construction land in Qixingguan District from 2009 to 2020 (hm2,%).
