Effects Of Irrigation Frequency And Planting Patterns On Grain Yield And Water Use Efficiency Of Winter Wheat

As a basic natural resource and strategic economic resources, the water is a controlled factor of ecological environment. Long-term accumulated environmental problems of water resources, has become an important restricting factors of economic development and social development, especially the development of agriculture. As a main winter wheat producing area, under the limited water resource how to guarantee or even improve the food production became a problem to be solved.The study area was located at the Agronomy Experimental Station of the Shandong Agricultural University during the winter wheat growing seasons of 2013-2014 and2014-2015. The effects of planting patterns and irrigation frequency treatments were quantified according to tiller number, grain yield, and water use efficiency(WUE). The two planting patterns applied were wide-precision and conventional-cultivation. Each planting pattern had three irrigation regimes, i.e., 120 mm irrigation only at the jointing stage, 60 mm irrigation at both the jointing and heading stages, and 40 mm irrigation for each of the jointing,heading, and milking stages. The results were as follows:(1) Reduce the irrigation frequency has a significant influence on winter wheat waterconsumptionIn the both growing seasons, whether wide-precision planting pattern or conventional-cultivation planting pattern, soil water consumption of winter wheat significantly decreased with decreased irrigation frequency. In the both growing seasons,Compared with 40 mm irrigation for each of the jointing, heading, and milking stages, the soil water consumption in 120 mm irrigation only at the jointing stage and 60 mm irrigation at both the jointing and heading stages was significantly decreased. Under the same irrigation frequency, there were no significant differences in the soil water consumption between the two planting patterns. Since all the treatments had the same irrigation amount and precipitation, the differences in total water consumption among different treatments were mainly determined by soil water consumption. Hence, the differences among total water consumption were similar to the soil water consumption. There were no significant differencein temperature and humidity between the two planting patterns; however, in the late winter wheat growth stages, I1 and I2 had a higher canopy temperature, which could reduce the evaporation amount. Also, in the late winter wheat growth stages, I1 and I2 had a higher transpiration rate, which could improve the effective water consumption. Under the wide-precision planting pattern reducing the irrigation frequency is a more effective way to realize the effective use of water, so as to improve water use efficiency.(2) Under the wide-precision reducing the irrigation frequency has a significant influenceon winter wheat grain yield.Grain yield was significantly higher in the wide-precision planting pattern than in the conventional-cultivation planting pattern in both winter wheat growing seasons. For the total120 mm irrigation amount, irrigation frequency had a significant influence on 1000-kernel weight and spike number. Reducing the irrigation frequency could improve spike number, and reduce 1000-kernel weight. I3 had the highest tiller extinction rate, followed by I2, followed by I1, which could determine the spike number. Under the wide-precision reducing the irrigation frequency could increase LAI, CCI and PAR canopy capture, which could promote the photosynthetic rate, thereby increased the grain yield.(3) Under the wide-precision reducing the irrigation frequency has a significant influenceon winter wheat water use efficiency.In both growing seasons, WUE were significantly higher in wide-precision planting pattern than in conventional-cultivation planting pattern, and WUE were significantly higher in I1 and I2 than in I3. Under the 120 mm irrigation amount, reduced irrigation frequency could significantly increase WUE in the both planting patterns. Under the wide-precision planting pattern, WUE of 120 mm irrigation only at the jointing stage and 60 mm irrigation at both the jointing and heading stages were much higher than the other treatments.Considering that there are no significant differences between WI1 and WI2 in grain yield,water consumption, or WUE of winter wheat, I2 could significantly increase grain yield. We propose that wide-precision planting pattern irrigated with 60 mm at the jointing and heading stages of winter wheat should be widely applied in the North China Plain.