Background Rainfall is the main cause of hydraulic erosion, and the geographical differentiation pattern of rainfall is the main cause of the difference in hydraulic erosion characteristics of various regions. Therefore, it is of great significance to study the characteristics of rainfall time variation for regional soil and water conservation. Tang-Qin region is one of the areas with the most serious soil erosion in Hebei province. Soil erosion has varying degrees of impact on the agricultural production and development of the region and the formulation of soil erosion control measures. Thus, the analysis of the rainfall change trend in the Tang-Qin region will reduce soil erosion, and the protection of downstream water sources is of great significance.

Methods This paper mainly applied the change trend and mutation analysis method (Mann-Kendall test) to analyze the annual rainfall and erosive rainfall changing trends and mutations of the rainfall data at 5 stations in the Tang-Qin region from 1960 to 2015. Data are from China Meteorological Network.

Results 1) The average annual rainfall in Tang-Qin region was 639.19 mm, showing a downward trend of fluctuations, with an average annual decrease of 1.46 mm; the average annual erosive rainfall was 443.78 mm, showing a downward trend of fluctuations, with an average annual decrease of 1.58 mm. 2) The seasonal rainfall was characterized by the most rainfall in summer, with an average rainfall of 466.15 mm, accounting for 72 % of the annual rainfall, followed by spring and autumn, and the least in winter; summer rainfall showed a declining trend, with a climate tendency of -3.001 1/a. The rainfall in the spring, summer and winter showed a rising trend, with climate tendency rates of 0.508 3/a, 0.458 6/a, and 0.207 5/a, respectively. 3) In summer, erosive rainfall showed a declining trend, with a climatic tendency rate of -2.227 5/a, and erosive rainfall in the spring and autumn showed a volatile fluctuation trend, with a climatic tendency rate of 0.194 6/a and 0.536 1/a, respectively. 4) Sudden changes in annual rainfall occurred in 1996 and 2011, and sudden changes in annual erosive rainfall occurred in 2012. Seasonal changes, sudden changes in the spring and erosive rainfall in 1965 and 2013, and sudden changes in the summer and erosive rainfall in 1989 and 2012, the sudden change point of autumn rainfall was 2003, the sudden change year of erosive rainfall was 2006, and the sudden change year of winter was 1984.

Conclusions The terrain in the Tang-Qin region is complicated, the pattern of rainfall changes is variable, the summer rainfall is heavy and the erosive rainfall is large, and the prevention and control of soil erosion needs to be strengthened. Meanwhile, this pattern may provide a basis for monitoring soil and water conservation in the Tang-Qin region.