In order to understand the effects of planting modes and agriculture drainage ditches

nitrogen and phosphorus concentration

and suspended solids characteristics of the runoff in different types of agriculture drainage ditches from different planting area (vegetable area

corn field and greenhouse area) in the Chaihe watershed were analyzed based on the survey and monitoring of water samples under natural rainfall. The main results are as follows: (1) The average total nitrogen(TN) and total phosphorus(TP) contents (27.16 mg/L and 17.18 mg/L) in runoff were much higher than class V surface water quality standard limits in China

and the dissolved nitrogen (DN) and particulate phosphate were the main pollutants; (2) Rainfall was one of the most important factors influencing runoff pollutant contents

and planting mode also had the significant effect on TN

DN

and dissolved phosphorus (DP) (P＜0.05); (3) When the rainfall was the same (18.05 mm)

the higher contents of nitrogen in runoff from vegetable area and greenhouse area (TN: 32.26 mg/L

29.02 mg/L; DN: 21.33 mg/L

17.46 mg/L) and the higher phosphorus contents from vegetable area (TP: 17.46 mg/L

DP: 2.16 mg/L) were found. In addition

we also found that natural ditches would significantly decrease the contents of total phosphorus

dissolved nitrogen

and dissolved phosphorus (P＜0.05). In conclusion

planting mode was one of the main factors influencing non-point source pollution in the same rainfall. Though ditch can decrease effectively non-point source pollution

the contribution of ditch was less than the planting mode. Based on the above results

the planting structure of the watershed should be optimized at first

and then the transform of the existing ditches and the promotion of the ecological level are also needed to increase the control efficiency of the non-point source pollution.