Intra-annual dynamics of soil conservation features in Huanghua City

China is one of the countries in the world with the most severe soil erosion. Mastering various changes in regional soil erosion, soil conservation and ecological dynamics is critical for prioritization of regional soil and water conservation in time and space to combat soil erosion for sustainable development. At present, research on long-term soil conservation has ignored the erosion force of rainfall and the dynamic changes in vegetation coverage. Using GIS and Universal Soil Loss Equation (USLE), we calculated soil erosion and soil conservation amounts in a typical coastal saline soil region, Huanghua City of Hebei Province. Furthermore, using market value and soil opportunity cost, we calculated monthly soil conservation value in the study area. The dynamic characteristics of soil conservation in coastal land ecosystems were important for ecological security and the maintenance of China’s coastal areas. The results showed uneven monthly distribution of soil conservation values that was in agreement with the seasonal dynamics of soil conservation amount which peaked in August. The soil conservation value was zero for January, February, March, October, and December, while it increased from May to August. Soil conservation value from May to September accounted for 82.47% of the total of the year. Among different ecosystems, grassland showed the highest soil conservation value per unit area in August (128.87 Yuan·hm^-2). The soil conservation value per unit area of water body was minimum in September (11.23 Yuan·hm^-2). For different functions of soil conservation, the order of value contributions to soil conservation value per unit area was value of reducing soil fertility loss > value of reducing silt deposition > value of reducing land abandonment. The soil conservation values of different ecosystems in the study area changed obviously with season. In the rainy season, the heavy short-durational rains increased soil loss, when the soil conservation functions of ecosystems were more important for combating soil loss.