Background In recent years, due to the improvements of landuse transfer policies, the development of agroforestry activities had been enhanced significantly. However, the increasing of agroforestry activities aggravated soil and water loss, especially in hilly and mountain areas. Therefore, it became very important to understand the patterns and relationships between the agroforestry activities and its related soil and water loss.

Methods Rongcheng, the Key Control Area of Soil Erosion in Shandong province, was selected as the study area. In this area, remote sensing, field investigation, and soil erosion simulation were used to analyze the spatial and temporal distribution patterns of agroforestry activities. In addition, the effects of agroforestry activities on soil and water loss and its related environmental factors were quantified in this study.

Results 1) From 2014 to 2017, there were 36 plots (>2 hm², max.=62.5 hm², and min.=2.58 hm²) disturbed by agroforestry activities with a total area of 591.33 hm² involving 11 administrative districts. 2) Within the disturbed 36 plots, agroforestry activities resulted in the changes in engineering practices, micro-topographies (slope and slope length), and understory vegetation cover. Among those changes, the low-standard terraced farmland was transferred to high-benefit economic forest such as orchard with higher slope (mainly 2°-5°, followed by 5°-8°, and >8° accounting for 12%, and max.=19°), and longer slope length (avg.=300-500 m and max.=750 m). The vegetation coverage changed from high coverage to low coverage, and then steadily increased. 3) The agroforestry activities aggravated the severity of soil and water loss in those disturbed plots, and the intensity of soil erosion jumped from slight level to light and medium levels. Moreover, the erosion modulus of post disturbed plots increased 6-11 times than prior disturbed plots, and the disturbed plots did not recover to the original conditions even after a 4-year recovery period.

Conclusions Therefore, the increasing of agroforestry activities may accelerate the soil and water loss through destroying the understory vegetation cover and modifying local micro-topographies, especially in hilly and mountain areas. This research revealed the realistic situations and difficulties to restore the disturbed areas of agroforestry activities. Moreover, for the disturbed areas, more practical managements and policies need to be implemented to control agroforestry activities and soil erosion.