Research On The Construction Theory Of Ecological Irrigation District And Its Key Technology

Irrigation district plays an important role in development of nation's agriculture, society and economy. To construct ecological irrigation district, which be able to coordinate the water resources allocation better than traditional one and implement the sustainable development of agriculture, is the main orientation of irrigation district construction.Based on studying on the present state, main problems and perspectives of the irrigation district construction home and abroad, this paper analyzed the seriously effect the traditional irrigation district does to ecological environment, defined the conception of ecological irrigation district and summarized the fundamental theory applied in irrigation district construction.According to the construction principles of ecological irrigation district, this paper discussed on the construction mode of ecological irrigation district including water cycling use mode in irrigation-drainage system, landscape layout, canal structure form construction, canal cross-section style construction, canal impervious element technology, ecological canal forms, ecological canal revetment, pond and reservoir form construction and so on.Studying on the state of ecological canal construction technology home and abroad, this paper constructed the ecological canal technology system according with the characteristics of irrigation district, discussed on the basic ecological canal forms, the technology features and the application conditions, which provided the technology support to the ecological irrigation district construction.By means of field investigation and observation and interior examination, experiments were applied to study on the retention effect and purification law to N and P of different scales of canals, different cross-section styles of canals, different scales of ponds. The results showed that:(1) The retention and purification effect to N and P of canals has close relationship to the sort and number of hydrophytes, canal scale, velocity of flow etc. The sort and number of hydrophytes take the first place, followed by canal scale and velocity of flow. Under the condition of more hydrophytes with high enrichment ability, low velocity of flow and greater canal scale, the retention and purification effect will be better.