Research On The Dynamics Of Soil Water And Salt Of Purple Medic Grassland And Its Ecological Optimal Irrigation Control In Qinwangchuan Irrigated Regions In Gansu

On the basis of experiments a new thought and concept of ecological irrigation was posed in this paper. In the support of purple medic ecological irrigation idea, taking ecological irrigation system of purple medic in Qinwangchuan irrigated region in Gansu for example, the physiological influence of dynamics of soil water and salt upon purple medic was analyzed. The water production functions of purple medic and its optimal ecological irrigation pattern was then posed. With the method of systems engineering, the optimal distribution conclusions about purple medic's ecological and economical irrigation quota for the harvest of purple medic during early anthesis was obtained as well. The article figured out the transforming benefits of water—photosynthesis—yield in pasturage irrigation , and an innovative harmonious water and salt—grass—ecosystem ecological optimal irrigation system adapted in the interior arid irrigation area.The results showed that seedlings emergence decreased sharply under high soil salinity of 0.279%. And it almost stopped when the salinity went up to 0.428%. Along with the increasing of soil salinity strength during bearing period, ground biomass of purple medic underwent more inhibitory action than the underground part gradually, while the WUE reduced obviously. Under the joint water-and-salt stress, the conductivity and soil moisture content changed reversely after irrigation. The suitable concentration of sodium salt and magnesium salt could increase the proline content of purple medic, but the Cl existed suppressed the synthesis of amino acid. The condition that 8g/L and 15g/L of NaCl, NaHCO₃ and MgSO₄ showed that high salt strength corresponding high protein and the result above became one of the basic theories of ecological irrigation to achieve ideal quality through limited regulated deficit irrigation in purple medic vegetative stages. The conductivity showed a quite obvious partition function characteristic under different soil temperature gradients,...