Background Soil and water loss is widely distributed in mountainous and hilly areas of the west Guangdong province, and its potential danger is relatively large, meanwhile the causes of soil and water loss are complex and diverse. In order to lay out targeted prevention and control measures for water and soil loss, to clarify the overall layout of water and soil conservation in small watersheds and the arrangement of key control tasks, and to implement differentiated regional water and soil loss prevention and control strategy, this paper selects Junxu River small watershed in Gaozhou city of western Guangdong province as research area, analyzes the characteristics of soil and water loss and its dynamic change, and puts forward relevant prevention and control measures of water and soil loss.

Methods Using GIS & RS technology, taking the domestic high-resolution satellite remote sensing images of 2017 and 2021 as fundamental data, the single factor and current situation data of soil and water loss in small watersheds of 2017 and 2021 were analyzed and calculated. Combined with the current land use map, based on the average soil erosion modulus and high-intensity erosion structure index in the small watershed, the loss map of soil and water flow was determined, the dynamic changes of soil and water loss in small watershed were analyzed and evaluated, and then the prevention and control strategy of regional soil and water loss was proposed.

Results 1) According to the calculated results, the areas of water and soil erosion in the basin in 2017 and 2021 was 55.72 km² and 31.75 km² respectively, the area reduced by 23.97 km² and the reduction rate was about 43.02%. The intensity and area of water and soil loss lightened or reduced at varying degrees. However, various types of soil erosion still exist widely, which needs to be combined with the characteristics of water and soil loss of the basin, and to adopt the prevention and control strategy of water and soil loss in different areas to control water and soil loss. 2) By analyzing the current situation of soil and water loss in Junxu River small watershed of two stages, combined with the regional land spatial planning, the watershed can be divided into 3 types of areas: ecological protection area, treatment and development area and key regulation area for carrying out zoning prevention and control for three zones. Control strategies were proposed, such as strengthen prevention, promote natural ecological restoration, carry out dynamic monitoring and accurate control of water and soil loss, and promote the control strategies of sloping farmland, high-quality prevention and control of water and soil loss.

Conculsions The research results may provide data and technical support for the implementation of comprehensive management of soil and water loss in small watersheds in hilly areas of western Guangdong.