Changes in soil erosion in cropland in northeastern China over the past 300 years

Abstract

Accelerated soil erosion in cropland is a major threat to food production. However, northeastern China (NEC) is one of the most important food production areas in China, and soil erosion in this region has attracted little attention because of its flatter terrain and smaller sediment load than other regions in China. To obtain a clear understanding of cropland soil erosion in northeastern China on a historical basis, data on cropland area over the past 300 years and a 2012 national water conservancy survey were used to quantify the temporal and spatial changes in cropland soil erosion in northeastern China from 1653 to 2012. From 1653 to 2012, a total of 44.28 Gt of soil eroded from cropland in northeastern China at an average rate of 0.12 Gt yr−1, and 53% of this erosion occurred after 1950. Controlled by the intensity of the opening up of waste land, the average cropland erosion rate was low from 1653 to 1949, it increased dramatically between 1950 and 1980, and it decreased after the implementation of ecological policies after 1999. The annual soil loss was 0.01 Gt yr−1 for 1653–1739, 0.04 Gt yr−1 for 1740–1791, 0.09 Gt yr−1 for 1792–1910, and 0.15 Gt yr−1 for 1911–1949, whereas the values were 0.37 Gt yr−1 for 1950–1999 and 0.46 Gt yr−1 for 2000–2012. Cropland erosion mainly occurred in Liaoning (Liao) Province before 1780 but has expanded to Jilin (Ji) and Heilongjiang (Hei) Provinces since then. By 1980, 42% of the land in NEC had been cultivated, and 78% of that land was being eroded at an erosion rate higher than the tolerance soil loss (T); these proportions became 46% and 82%, respectively, by 2012. Hei Province contained the largest eroded cropland area after 1950. The exponential increase in the cropland soil loss resulted from the increase in the cropland acreage in the steep slope area.