Study On Water Consumption Rule During The Fallow Period And Sowing With Water Technique Of Spring Wheat In Arid Area

The paper was based on the field experiment in Wu wei Irrigation Experiment Station in Gansu province from August 2007 to July 2008. According to different storage irrigation quato and different sowing and tillage mode, it designed four different treatment.Through the observation and analysis of water soil content, soil water evaporation, physiological and ecological index and field of spring wheat, water evaporation rule in fallow period and Sowing with water technique of spring wheat was Studied, the main results as follows:1. With the technique of water-saving storage irrigation and no-tillage soil water evaporation could be decreased effectively. The storage irrigation quota of 900 m3/hm2 could reduce water deep percolation of 35mm and soil water evaporation of 15 mm. Compared to CI, Soil water storage variation of LI in 1m depth only decreased 10 mm during fallow period. Soil water evaporation under the two treatments of no storage irrigation was descreased by 60mm more or less than CI.2. Sowing with water and of Water Retaining Agent to ANSW and SNSW could increased and keeped soil water content of 20-30cm depth, and reach Suitable soil water condition for spring wheat seedling. The emergence rate of ANSW and SNSW were both reach 91%, and There were no obvious difference amongthe four treatments. At later seeding stage, the Soil water storage of ANSW and SNSW were limited, so the irrigation time of the two treatment should be advanced to meet the water demand of spring wheat.3. At booting stage, the daily water consumption of ANSW and SNSW were lower than CI and LI obviously. The irrigation of ANSW and SNSW at jointing stage was almost consumed by crop growth, and it didn't increase the soil water storage actually. Crop water requirement of spring wheat at booting stage is relatively great, the irrigation couldn't meet the requirement for crop growing normally, so the crop growth was retarded to some extent and the daily water consumption was descreased. This phenomenon could be named as late effect or hysteresis effect of the model of No irrigation-Sowing with water. So the irrigation cycle of the two treatment should be shorted to meet the water demand of spring wheat at the vigorous growth period .4. Because of short of water at booting stage, the increasing trend of LAI and plant height under ANSW and SNSW treatment slowed down. The growth Rate of ANSW and SNSW improved sharply after rewatering at filling stage, and the gap of LAI and plant height between four treatments is deflated gradually, but compared to CI and LI the peak of ANSW and SNSW still had certain gap.5. Compared to CI, the field of ANSW, LI and SNSW descreased by 10.87%, 5.02% and 6.16% respectively, but WUE of them improved 0.36kg/mm·hm2, 0.20kg/mm·hm2 and 0.63kg/mm·hm2 respectively, And IWUE of ANSW, LI and SNSW increased by 1.03kg/mm·hm2, 0.41kg/mm·hm2 and 1.30kg/mm·hm2. These Water-Saving technique could improve WUE efficiently.6. According to Analsis Hierarchy Process(AHP), the comprehensive adaptability of four treatments was evaluated from three aspects(moisture index, physiological and ecological index and economic index). The results showed that although the physiological and ecological evaluation value of CI and LI was higher than ANSW and SNSW, but the moisture and economical evaluation value of CI and LI was far lower than ANSW and SNSW. The size order of the comprehensive evaluation value under different treatment was SNSW>ANSW>LI>CI. The results showed that the comprehensive adaptability of SNSW was highest, ANSW and LI is lower, CI was lowest in shiyang river basin.