Effects Of Plastic Film Mulching And Seed Rate On Water Use Efficiency In Maize/Sunflower Intercropping System

For the issues such as the significant consumption of water, low per unit water production efficiency, etc.of the traditional intercropping in northwestern oasis irrigation area, this thesis discusses the effects of differentmulching patterns and the seeding rates forsunflower on the output of composite populations consisting of theintercropped maize and sunflower, yield of maize as well as water production efficiency and analyzes the basicmechanism for water production efficiency of maize intercropped with sunflower by field experiment. Themain conclusions obtained are as follows.1. Compared with the solo maize, the water production efficiency can be greatly improved by theintercropped maize and sunflower. Under the low, moderate and high seeding rates of sunflower, the waterproduction efficiency for the intercropped sunflower and maize covered by mulching film is respectively12.4RMB/m3,13.3RMB/m3and12.8RMB/m3; while that for the intercropped sunflower and maize withoutmulching films is respectively up to12.3RMB/m3,12.6RMB/m3and12.8RMB/m3, which is obviouslygreater than that of solo maize. Compared with the solo maize, the total output of the intercropped sunflowerand maize covered by mulching films is respectively increased by104.7%,104.9%and111.2%while the totaloutput of the intercropped sunflower and maize without mulching films is99.6%,104.6%and101.3%. Theoutput of the intercropped maize has been up to85.62%~93.95%of that for solo maize.2. The water consumption during the whole growth period of composite populations is not obviouslyincreased by the intercropped maize and sunflower. Compared with the weighted average of the waterconsumption for the solo maize, the water consumption of the intercropped maize accounts for97.39%~103.10%of that for the solo maize. Among the intercropped populations, after the cut-flower of sunflower, the waterconsumption of intercropped maize will be greater than that of solo ones and the water consumption of theuncovered sunflower is obviously higher than that of the solo maize.The weighted average E/ET of thecovered intercropped sunflower and maize is decreased by10.92%~11.46%compared with the covered solosunflower and that of the uncovered intercropped sunflower and maize is decreased by9.84%~18.02%compared with the uncovered solo sunflower..Mulching film reduces invalid use of water after sunflower cut.3. The film mulching increases the emergence rate and cut-flower number of the sunflower and shifts thecut-flower of sunflower to an earlier time while decreasing the commodity rate of sunflower; the filingmulching increases the dry matter accumulation rate and the height, stems as well as diameter of flower disc of covered sunflower plant are6.4%~12.3%,8.0%~12.5%and5.4%~7.3%greater than those of uncoveredsunflower.4. The main causes of water production efficiency increased by the intercropped maize and sunflowermainly lie in that the LAID has been increased by intercropping and a gradient difference of soil moistureappears in the sunflower zone and the corn zone after cut-flow of intercropped sunflower which decreases theaccounted proportion of water consumption by the evaporation amount (E/ET) of the individual plant andincreases the ground temperature. Under the low, moderate and high seeding rates of sunflower, the LAID ofcovered intercropped sunflower and maize is increased by69.73%~80.43%than the weighted average LAIDof the covered solo sunflower, and the LAID of uncovered intercropped sunflower and maize is increased by166.92%~177.28%than the weighted average LAID of the uncovered solo sunflower. After cut-flower ofsunflower, the average soil moisture of the covered intercropped sunflower zone is4.26%~4.61%higher thanthat of corn zone and the average soil moisture of the uncovered intercropped sunflower zone is7.37%~7.83%higher than that of corn zone after cut-flower of sunflower; The increased ground temperature of coveredintercropped sunflower and maize is1.52℃~1.57℃than that of uncovered ones. For the intercropping pattern,the ground temperature of the sunflower zone is lower than that of corn zone during the whole growth period;The temperature of covered sunflower zone is respectively1.52℃~2.68℃lower than that of the corn zonewhile the temperature of uncovered sunflower zone is respectively3.00℃~3.45℃lower than that of the cornzone.