Dynamics of soil wind erosion in the Mu Us sandy land (in northern China) affected by cropland reclamation from 2000 to 2020

In recent decades, the wind speed displayed an obvious declining trend in northern China. Under this background, large amounts of grassland and sandy land have been reclaimed into cropland in the Mu Us Sandy Land (MUSL), and whether cropland reclamation will cause an increase in wind erosion has aroused widespread concern. Additionally, there are two reclamation patterns including croplands reclaimed by herdsmen and enterprises in this round of cropland reclamation, whether the different reclamation patterns will induce differential wind erosion is also a scientific question. These questions have influenced the policy of cropland reclamation. Consequently, the Revised Wind Erosion Equation (RWEQ) validated by field observations was applied to simulate the wind erosion of the MUSL from 2000 to 2020. Furthermore, by simulating the wind erosion modulus (WEM) under different scenarios, the climatic fluctuations and cropland reclamation effects on the WEM were distinguished. The results showed that the WEMs of the MUSL decreased during the simulated period. Moreover, the average annual WEM of croplands reclaimed by herdsmen was higher than that reclaimed by enterprises by 18.49% and 12.85% during the 2015 phase (during 2013 to 2017) and 2020 phase (during 2018 to 2020), respectively. The average WEM of the newly reclaimed croplands (reclaimed after 2013) increased 42% relative to the old croplands (reclaimed before 2013), but compared with the original land use types, the WEM of newly reclaimed cropland decreased by 134.55 and 158.94 t/km2/a (annum) during the 2015 phase and 2020 phase, respectively. During the fallow period of the cropland reclaimed by enterprises, the WEM was two times as high as that during planting, so corresponding measures to reduce wind erosion during fallow should be implemented. This study resolves the question of whether cropland will lead to an increase in wind erosion and provides valuable information for reclamation in the MUSL.