The land-use and land-cover change characteristics and driving forces of cultivated land in Central Asian countries from 1992 to 2015

Five countries located in the center of Eurasian continent (i.e., Central Asian countries) are important nodes along the Belt and Road Initiative, a global development strategy launched by China. The Central Asian countries' land-use and land-cover change (LUCC) characteristics from 1992 to 2015 were analyzed. The European Space Agency Climate Change Initiative global land cover data were used to determine the land-use degree, dynamic attitude, and transfer matrix by geographic information system (GIS) spatial analysis, and the driving force of cultivated land was explored using geographical detectors. The results showed that in the Central Asian countries, the area of cultivated and urban lands continuously increased, and that of forests, grasslands, and water areas decreased. Forests (7.88×10⁴ km²) and grasslands (5.27×10⁴ km²) were converted into cultivated land, and cultivated land (0.50×10⁴ km²) was converted into urban areas. The transfer between land-use types was country-specific (e.g., cultivated land was created from forests and grasslands in Kazakhstan, Kyrgyzstan, and Tajikistan and from unused land in Turkmenistan; cultivated land became urban areas in Uzbekistan) and closely associated with human activities. Urban land had the highest growth rate in all countries, followed by cultivated land (except in Uzbekistan), and cultivated land was the most variable land-use type. The land-use degree slowly increased (comprehensive index of land use degree was 193.34 in 1992, 197.41 in 2015), indicating that land-use was in the development stage. Land-use types ranked as follows (by land-use degree): cultivated lands > forests > grasslands > unused lands > water areas > urban lands. The driving forces for cultivated land changes were analyzed using geographical detectors and showed that the annual average precipitation had a significant effect. Social and agricultural factors also played a decisive role in the short term. The total population and rural population had the greatest influence on cultivated land expansion, followed by the per unit area grain yield. Interactive detection showed that interactions between factors were mutually reinforcing. In particular, super-positioning rural population and crop production index explained cultivated land expansion. The primary factors affecting cultivated land expansion were population growth and agricultural production improvement. These results are useful for planning sustainable land use in Central Asian countries.