Estimation of farmland soil wind erosion using RTK GPS measurements and the 137Cs technique: A case study in Kangbao County, Hebei province, northern China

Soil wind erosion in northern China has become a serious environmental problem, especially on cultivated soil, but data on soil loss by wind erosion are scarce due to limitation in effective measurement methods. The objective of this study is to introduce differential global positioning system (GPS) measurements into studies of wind erosion and obtain field measured data of soil wind erosion rates during previous decades in Kangbao County, a representative area suffering from serious farmland wind erosion in northern China. Vegetative banks that were maintained between farmland plots after the original grassland had been cultivated into stripped farmland were assumed to have experienced little erosion or deposition. As a result, these banks offer a useful reference for GPS measurements in estimations of soil loss by wind erosion in the adjacent farmland plots. Differential GPS and real-time kinematic (RTK) measurement show that almost a half centimetre of top soil has been blown away in this area every year since the soil had been cultivated in the early twentieth century. To examine the reliability of the GPS measurements, average wind erosion rate in this area was derived from the 137Cs model in 30 farmland plots, which was 0.55 cm a−1 or 89.5 t ha−1 a−1. Results of both methods show the study area has been experiencing severe wind erosion, which has caused serious local environmental problems and made this area an important source of blown sand and dust that threatens the Beijing and the Tianjin metropolitan area. Both methods have advantages and limitations and generally each of them cannot be replaced by another; however, this paper presents an example that a combination of applying RTK GPS measurements in special plots with using 137Cs techniques on the regional scale produces very helpful results of regional wind erosion.

Research highlights▶ GPS measurement and 137Cs model estimated soil wind erosion on farmland reliably. ▶ Farmland wind erosion in Kangbao caused local and off-site environmental problems. ▶ RTK GPS measurement and GIS methods can quantify wind erosion produced topography.