Effects of man-made ditch on eco-environment:A research review.

Man-made ditch is the artificial channel excavated for drainage and irrigation.As the corridor of drained and irrigated water,it can improve soil structure,promote crop growth,and thus,improve crop output.The existence of man-made ditch also has great effects on the environment around,among which,hydrological effect is the most available and acceptable one.Observations during and after rain events showed that man-made ditch contributes effectively to the runoff at the outlet.Some of the ditches can collect water and transfer it towards river,and the others can collect water and make it slow down.In this paper,the effects of man-made ditch on hydrology,element geochemistry,organisms and their habitats,and whole eco-environment were summarized,and suggestions on its further study were put forward,with the aim of exerting the effects of man-made ditch to benefit eco-environment.