Through simulating artificial rainfall in sloping land

this study investigated the impact of soil surface crust on runoff

sediment

and phosphorus and potassium losses from the different lands with no crust

light crust or heavy crust.Results showed that

heavy curst decreased runoff discharge and sediment loss.The declining process of phosphorus and potassium losses with runoff and sediment was a power equation

and the losing velocity of phosphorus and potassium was the fastest for no crust land.With the different development status of soil crust from no crust to heavy crust

the dominant position of the sediment extractable potassium loss was replaced gradually by the dissolved potassium loss

but the extractable phosphorus loss was dominant all the time.As compared with no crust land

the total amount of phosphorus and potassium loss was decreased by 20% and 9% for light crust land respectively

and reduced by 52% and 77% for heavy crust land respectively.It implies that soil crust may decrease soil nutrient loss and control soil quality degeneration tendency.