Under the conditions of three different types humic acid on erosion and nutrient loss on loess slope experiment above the same amount of 18 L/min in the Chinese academy of sciences agricultural ecological experimental station of the loess plateau

analyzed the impact of different types humic acid (NHA

FA and BFA) and humic acid in different amount on soil erosion and nutrient loss. Results showed that the different amount of NHA treatment

runoff increased with time. Compared with the slope runoff of 500 g/㎡

NHA content of 150 g/㎡ and 300 g/㎡was 1.14 times

1.08 times respectively. Sand content and concentration of Br- both decreased with the increase of time

cumulative runoff

sediment accumulation

the cumulative loss both decreased with the increase of dosage

slope cumulative runoff of 150 g/㎡

300 g/㎡was 2.16 times

1.87 times as much as 500 g/㎡

Br- cumulative loss was 1.38 times

1.23 times as much as 500 g/㎡. Dosage of 500 g/㎡ NHA to prevent soil erosion and nutrient loss was the best. Under different concentrations of FA

runoff increased with time

the cumulative runoff of concentration of 0.1%，0.03% was 1.19 times，1.33 times of 0.05% concentration

Br- concentration and rate of sand containing substantially reduced with increasing time

cumulative runoff

accumulated sediment and cumulative loss decreased firstly and then increased with increasing concentration

the sediment loss of the concentration of 0.1%

0.03% was 3.03 times

4.09 times as much as 0.05%

cumulative Br- loss was 1.1 times，1.26 times to the total loss of 0.05%Br-

and the effect of 0.5% FA concentration on soil erosion and nutrient loss was the best. Under different concentrations of BFA

runoff increased with time

slope cumulative runoff of BFA concentration of 0.1%

0.05% was 1.15 times

1.1times as much as 0.03%

sandy rate and Br- concentration decreased with increasing time. Cumulative runoff

sediment accumulation increased with the increase of the concentration

?however

cumulative runoff increased firstly and then decreased with the increase of concentration

the cumulative sediment of concentration of 0.1%

0.05% was 1.36 times

0.49 times as much as 0.03%. The total loss of 0.01%Br- and 0.03% Br-was 4.06 times

3.5 times as much as 0.05%Br-

and the effect of 0.5% BFA concentration on soil erosion and nutrient loss was the best. Comprehensive consideration of the effect of three different types of humic acid to prevent erosion and nutrient loss on the slope was BFA>FA>NHA.