Abstract:

The Mu Us Sandy Land, located in the agro-pastoral ecotone of northern China, has a fragile ecological environment highly susceptible to agricultural development. This study employs long-term multivariate remote sensing data to analyze the spatio-temporal patterns of newly cultivated and abandoned farmland in the region from 1964 to 2020 and their subsequent impacts on desertification. The results indicate that (1) From 1964 to 2020, changes in the area of newly cultivated and abandoned farmland in the Mu Us Sandy Land can be categorized into three stages. Between 1964 and 1986, the extent of both newly cultivated and abandoned farmland was relatively high, with abandoned farmland significantly exceeding other periods. The average annual abandoned farmland area was 2.89 times that of 1986—2020, and newly cultivated farmland in pastoral areas was notably greater than that in agricultural areas. Between 1986 and 2007, both newly cultivated and abandoned farmland remained relatively low and stable, with newly cultivated farmland slightly exceeding abandoned farmland. From 2007 to 2020, the area of newly cultivated farmland expanded rapidly, with an average annual increase 3.24 times that of 1964—2007, while the abandoned farmland area remained relatively low. (2) Significant spatial and temporal differences exist between newly cultivated and abandoned farmland. From 1964 to 1986, newly cultivated farmland hotspots were widely distributed in the pastoral areas of central and western Mu Us Sandy Land. Between 1971 and 1986, a few concentrated cultivation hotspots emerged in the agricultural areas of eastern Mu Us Sandy Land. From 2007 to 2020, newly cultivated farmland hotspots were mainly concentrated in the east, central agricultural areas, and the southern region. (3) Between 1964 and 1986, large-scale farmland cultivation and abandonment, driven by policy factors, led to severe land desertification in the Mu Us Sandy Land. The area of fixed sandy land surrounding abandoned farmland decreased by 99.9%, while the area of shifting sandy land increased by 358.2%. From 2007 to 2020, no significant trend of desertification was observed around newly cultivated farmland; however, the degree of desertification surrounding newly cultivated farmland showed an increasing trend. Future agricultural and animal husbandry management policies, as well as desertification prevention and control plans, should carefully balance agricultural development with the preservation of fragile sandy ecosystems. Additionally, attention should be given to the potential desertification risks associated with land reclamation and abandonment.

Key words: newly cultivated farmland, abandoned farmland, spatio-temporal pattern, desertification, Mu Us Sandy Land