Gully erosion is the destructive and dramatic form of land degradation in Northeast China. The region is the grain production and ecological security base of China where the fertile and productive Mollisols are distributed. Though the region was agriculturally developed relatively recently, it went through high intensity cultivation and fast succession processes within short-time scales. Coupled with irrational farming practice choice and land use, hillslope erosion and gully erosion are seriously threatening agricultural production and environmental stability in the region. The awareness of gully erosion by the local governments started in the 1970s, and conservation measures were thus implemented. In this paper, based on our survey, communications with local farmers and stakeholders as well as investigation for gully erosion for the past three years, we summarize the practical and efficient practices to manage gully erosion developed by researchers and farmers in Northeast China during the past 50 years. These practices include various drop structures, soil check dams, masonry check dams, gabion check dams, wicker check dams, continuous live wicker, a shrub plant enclosure, and an arbor plant enclosure. We specifically expound how a gully erosion practice is set up and identify the site conditions for which they are well-suited. The application of these practices depends on topography, gully size, and local economy. Bioengineering techniques in Northeast China, such as continuous live wicker, a shrub plant enclosure, and an arbor plant enclosure, are highly effective in controlling gully erosion. Problems and challenges are also presented.
Gully erosion stands out as one of the worst aspects of farmland degradation, which induces the loss of arable soil and tractor operation. Most of the gully erosion studies focused on the influence of precipitation erosion, slope erosion, and the freeze–thaw cycle on soil characteristics. Few studies discussed the effect of snowmelt on gully development. In this paper, the gully development induced by snowmelt was observed in a typical gully in Hailun City, the center of the Mollisols area of northeast China. The results showed that, during the snow melting period of 2017, the soil loss induced by snow melting was 0.22 t at the gully head + 0 m, 14.27 t at the gully head + 77 m, and 7.63 t at the gully head + 239 m, while 98.1% of the sediment was from the gully erosion. The horizontal projected area of the observed gully increased by 56.96 m2, and the gully head advanced 2.3 m during the snow melting period. About 92.2% of the total runoff occurred in the initial snow melting period. The discharge runoff and sediment concentration had a significant correlation with the air temperature above 0 °C, and the same relationship existed between the discharge runoff and sediment concentration in the initial and middle snowmelt stages. The results indicate that the gully development induced by snowmelt should not be ignored in the area.