Soil surface roughness (SSR) is an important factor affecting soil erosion and soil nutrient transport. Human tillage leads to increased instability in SSR, and the characteristics of SSR caused by different tillage practices await further study. This research utilizes terrestrial laser scanning (TLS) to measure the SSR of six farmland plots (25 m x 25 m) and analyzes the characteristics of SSR under different tillage practices (plowing, harrowing, ridging, crusting, etc.). The study results show: 1) Different agricultural tillage practices lead to significant differences in SSR. The plowed and harrowed plot corresponds to the maximum (2.49 cm) and minimum (1.5 cm) root mean square height (RMSH), respectively. Correlation length (CL) is more affected by different tillage practices than RMSH. The difference in CL between the ridged and harrowed plot is 2.6 times. 2) Ridging and crusting caused significant directional variation in SSR. The SSR anisotropy of the harrowed plot can be disregarded. 3) Under the condition of measuring soil profile in 12 directions and randomly sampling 70 times in each direction, the profile length must be at least 3 m to ensure that the measurement error of SSR is better than 5% compared to the true value. TLS can measure two-dimensional SSR. Therefore, it is only necessary to ensure that the measurement range is at least 3 m x 3 m. The study results provide a reference for the high-precision measurement of SSR (RMSH and CL) under different agricultural tillage practices.

High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small- and medium-sized mountain glaciers. In this study, we use a high-precision local remote sensing technique, long-range terrestrial laser scanning (TLS), to measure the evolution of Urumqi Glacier No. 1 at an annual scale. We found that the dense point clouds derived from the TLS survey can be used to reconstruct glacier surface terrain, with certain details, such as depressions, debris-covered areas, and supra-glacial drainages can be distinguished. The glacier experienced pronounced thickness thinning and continuous retreat over the last four mass-balance years (2015 - 2019). The mean surface slope of Urumqi Glacier No. 1 gradually steepened, which may increase the removal of glacier mass. The glacier was deeply incised by two very prominent primary supra-glacial rivers, and those rivers presented a widening trend. Extensive networks of supra-glacial channels had a significant impact on accelerated glacier mass loss. High-precision measuring is of vital importance to understanding the annual evolution of this type of glacier.