Study On The Mechanism Of Water-Saving, Increasing Rpoduction And Its Effect Under Moisture Conserving Irrigation(MCI)

This paper is based on the new idea of water-saving named moisture conserving irrigation brought forward by professor Wu and Professor Wang. As a brand new water-saving concept, there is much to research on moisture conserving irrigation. This paper concentrate specially on three soil moisture conserving technologies such as plastic mulch, straw mulch and chemical controlling (Polyacrylamide—PAM).We researched theprocess of soil-plant interface, water-saving and yield incensement applied by applying these technologies to ground irrigation,combined with the laboratory tests on field experiment. The conclusion has been drawn as follows:1. Foundation of the temperature-forecasting model by analyzing the effect of temperature, humidity in the field.(1) Simulated the temperature function of soil surface and 5cm underground with time, and there are linear correlativity between soil temperature 5cm underground and air temperature in different treatment such as plastic mulch, straw mulch and PAM treatment.(2) Confirmed the representative time of soil temperature at different soil depth under MCI in a day. Based the soil temperature data tested at different time in the field, found the connection model soil profile temperature at the characteristic time, opened out the changing rules of soil temperature, soil water, air humidity 5cm above soil surface and the connection among them under the MCI of straw mulching. Furthermore, we found maximal soil temperature at the soil profile changes exponential descending with the depth increasing.(3) Based on the BP ANN, the forecasting model of soil temperature was founded and takes better forecasting result.2. Different effect of depositing water and preventing soil moisture evaporation under different MCI.(1) The main difference of soil water content is embodied in the soil 0~50cm and decreased with the depth incensement.(2) Before routing stages, the order of water consume from lager to lower CK, chemical control, straw mulch and plastic mulch. Later the order from lager to lower is plastic mulch, straw mulch, CK and chemical control. The total water consumes from lager to lower are CK, chemical control, straw mulch, plastic mulch respectively.(3) The analysis showed that there can save irrigation water from 500m3 to 800 m3 when implement irrigation under plastic mulch or straw mulch, and still 150 m3~450m3 when adopts MCI under chemical control with PAM.