Abstract: To clarify the pollution load of adsorbed nitrogen of the Yellow River Delta in the nonpoint source pollution, we estimated soil erosion and adsorbed nitrogen pollution loads every five years from 1991 to 2020 in Yellow River Delta, based on the Chinese Soil Loss Equation and pollution load model, combined with the data of precipitation, land use, and nitrogen content in soil surface. The results showed that from 1991 to 2020, the average adsorbed nitrogen load modulus in the Yellow River Delta decreased from 701.94 to 361.51 kg·km^-2·a^-1, and the overall pollution load presented the fluctuation to descend. The result of the adsorbed nitrogen pollution load in 1995 was greater than 0. The area having a pollution load was 1317.29 km², accounting for 45.1% of the study area. By 2020, the area with pollution loads decreased to 765.31 km², accounting for 26.2% of the study area. Rainfall and changes of cultivated land area had a significant positive correlation with the adsorbed nitrogen pollution load, and were important driving forces for the changes of pollution load, consistent with the characteristics of the area where the high non-point source pollution load was located in the study area.

Key words: non-point source pollution, adsorbed nitrogen load, soil erosion, Yellow River Delta.