To effectively control soil erosion and non-point source pollution of slope-farmland in purple hilly

the paper mainly studied the effect of different conservation measures on runoff

sediment and nutrient loss at natural rainfall conditions and crop yield of slope farmland by runoff plots location observation method

which deeply revealed the effect of biological carbon

poly propylene amide and straw mulching measures on controlling soil nutrient loss from slope farmland. Results indicated that: (1)Compared with the background value

the increase of soil nutrient content showed as SM (straw mulching)>PAM (polyacrylamide)>BC (biological carbon)

which indicated that the corn straw mulching measures could improve soil nutrient best

followed by polyacrylamide. (2)The effects of different soil management measures to control the runoff and sediment yield changed in order as SM>PAM>BC. Measures of BC

PAM

SM could reduce runoff 0.00%-54.55%

0.00%~85.79%

0.00%~92.39%

respectively

and the amount of sediment yield decreased by 2.67%~47.78%

5.87%~77.90%

11.47%~90.17%. In the medium and heavy rain

the effect of protective measures on reducing runoff and sediment was significant

but it was waked in rainstorm. (3)The effect of soil management measures on controlling nitrogen loss was in order as SM>PAM>BC. Compared with CK

under medium and heavy rain conditions

the total nitrogen loss of protection measures was reduced by 16.24%~76.29%

and hydrolytic nitrogen loss was reduced by 6.21%~81.93%; under the rainstorm condition

nitrogen loss was reduced by （-11.74%）~11.99%; hydrolytic nitrogen loss was reduced by （-9.87%）~17.39%. The results showed that corn straw mulching was the best method to control nitrogen loss. (4)The effect of different soil management measures on controlling the phosphorus loss was different. Protective measures of BC

PAM and SM under middle and heavy rain conditions could control total phosphorus loss effectively (15.00%~81.44%)

and the effect weakened ((-6.68%)~10.98%) under rainstorm condition. Compared with CK

the effect of protection measures on increasing corn grain yield was in order as SM (29.43%)>PAM (19.01%)>BC (12.66%). The soil management measures of biological carbon

polyacrylamide and straw mulching controlled soil nutrient loss from slope farmland effectively

and straw mulching measure controlled the best.