Abstract:Through the method of outdoor artificial rainfall simulation, the effects of different slopes (5°, 15°, 25° and 35°) and different planting patterns of Prunus humilis (one row, two rows and three rows) on nitrogen loss and runoff production in gneiss hillsides were studied. The results showed that:(1) The runoff yield time was advanced with the increasing of the slope gradient, and the average runoff yield time was delayed by 59.23% from three rows planting to one row planting, and it was delayed by 32.28% from two rows planting to one row plant, and the runoff yield intensity and fluctuation range of the different planting patterns followed the order of one row > two rows > three rows. (2) During the rainfall process, the nitrogen loss and the loss concentration of different planting patterns were sequenced as one row > two rows > three rows. Under the different slopes, the nitrogen loss and the loss concentration were sequenced as 5° < 15° < 25° > 35°, and the critical slope gradient was 25°. (3) On the same slope, the loss of nitrate nitrogen was the largest when the planting pattern was two rows to three rows, which decreased by 16.78%, 44.71%, 41.33% and 41.89%, respectively. (4) During the nitrogen loss process, nitrate nitrogen loss accounted for 40.35%, ammonium nitrogen loss accounted for 10.13%, and nitrate nitrogen was the main form of loss. (5) In the same planting pattern, there was a quadratic function between the loss amount and the loss concentration of the nitrogen and the slope, the correlation coefficients (R2) ranged from 0.531 to 0.999. On the same slope, the loss amount and the loss concentration of the nitrogen had linear relationship with the planting pattern, and the correlation coefficients (R2) ranged from 0.102 to 0.999. (6) Planting pattern was negatively correlated with nitrate nitrogen loss and ammonium nitrogen loss, which was the main factor affecting nitrogen loss. In the gneiss hillsides, planting P. humilis in multi-row staggered way could significantly reduce nitrogen loss.