| A field experiment was carried out under different irrigation rate at the oasis experimental station of Gansu Agriculture University, in Huangyang Urban,Gansu Province.Water use characteristics and influence factors of alternative irrigatted wheat corn intercropping and sole wheat, sole corn were investigatting, and high possible mechanism of water efficient utilization of intercropping system was discussed.The main results showed as following:1.Alternative irrigatted wheat corn intercropping could increase the land utilization efficiency,crop yield and WUE.At the irrigation rate of low, medium, high respectively, the LER of intercropping system was 1.30,1.35,1.38, the LER of intercropping was higher than that of sole cropping.In actual site area,the wheat yield of alternative irrigatted wheat corn intercropping was increased by 20.96%,28.34%,33.11% compared to sole wheat, the yield of corn was increased by 38.30%,41.65%,41.98% compared to sole corn, yield increasing effect of intercropping was significant. At three irrigation rate, WUE of alternative irrigatted wheat corn intercropping was increased by 55.97%,63.87%,68.47% and 8.29%,12.72%,14.02% compared to sole wheat and corn,the difference of intercropping and sole wheat was significant, the difference of intercropping and sole corn was significant only at medium,high irrigation rate. The effect of intercropping to wheat and corn economic yield were very significant, the effect of irrigation rate to wheat economic yield was not significant, the effect of irrigation rate to corn economic yield was significant; the effect of intercropping and irrigation rate to wheat WUE were very significant, to corn WUE was significant, the interaction effect of intercropping and irrigation rate to wheat,corn economic yield and WUE are all not significant.Intercropping was the main way which affected yield and WUE of crop.2.In Oasis area,the main influencing factors of wheat,corn WUE were LAI-D, whole growth stage rainfull and total irrigation amount.The correlation between LAI-D, rainfull of whole growth stage, total water consumption, soil moisture, yield, water consumption and WUE were not significant, but the correlation between LAI-D and yield was very significant(r=0.99388), the correlation between whole growth stage rainfull and yield was significant(r=0.98159), the correlation between total irrigation amount and water consumption was also significant(r=0.95825), the correlation between LAI-D, rainfull of whole growth stage and water consumption were not significant, the correlation between total irrigation amount and yield was not significant, too. Thus, LAI-D,whole growth stage rainfull and total irrigation amount were the key factors to determine WUE of crop, which affect WUE by affecting yield and water consumption.3. The main causes which increased WUE of alternative irrigatted wheat corn intercropping were: The economic yield increased with the improvement of LAI-D, whole growth stage rainfull,but water consumption was not increased significantly; in whole co-growth stage, the difference of soil moisture gradient between wheat and corn band was beneficial to optimize soil moisture environment of intercropping wheat band.At the irrigation rate of low,medium,high respectively,LAI-D of intercropping was increased by 54.18%, 54.49%, 60.04% compared to sole wheat,by 2.74%,1.52%,-0.10% compared to sole corn, the difference between intercropping and sole wheat was significant, but was not significant with sole corn.Whole growth stage rainfull of wheat corn intercropping was increased by 24.37% compared to sole wheat,which increased the yield of crop.Water consumption of alternative irrigatted wheat corn intercropping was increased by 5.38%,4.71%,4.19% compared to the average of sole cropping systems. At the irrigation rate of low, medium, high respectively, the difference between intercropping and sole cropping systems was not significant. In addition, absorption and utilization of soil moisture of intercropping system was higher than that of sole systems. The temporal and spatial distribution of soil moisture was sole wheat>sole corn>intercropping system, at the irrigation rate of low, medium, high respectively,in whole growth stage, soil moisture of sole wheat and corn were increased by 3.77%,7.20%,9.62% and 2.21%,2.89%,1.17% compared to intercropping system; as for spatial distribution, it was increased by 1.15%,3.43%,6.63% and 3.73%,2.45%,1.70% compared to intercropping system.Before wheat harvesting, soil moisture average of corn band was increased by 17.31% and 9.12% compared to intercropping wheat band and intercropping interlaced zone, this soil moisture gradient was good for the growth of intercropping wheat before wheat harvesting. |
