| Due to unique phenological conditions and geographical advantages,the Hebei Plain has become an important producing area of high quality wheat in China,and has made outstanding contributions to China’s economic construction,social development and national food security.However,the growth season of winter wheat is misaligned with the rainy season seriously,and the rainfall can not meet the water demand of growth.The yield and water use efficiency of winter wheat can be improved effectively by adjusting water distribution in the growing season of winter wheat.The growth process of winter wheat in the North China Plain is divided into two stages: pre-winter and spring.In order to solve the problem of winter and spring drought and ensure passing winter safely,normal greening and late growth of winter wheat,this study conducted a winter wheat irrigation experiment at the Experimental Station of dry farming and water-saving Agriculture of Hebei Academy of Agriculture and Forestry Sciences from 2021 to2022.The experiment adopted a two-factor split zone design,and the main factor was overwintering water treatment,which was divided into overwintering water(M)and no overwintering water(N).The secondary factor was irrigation time in spring,and irrigation was carried out twice in spring,among which the first irrigation time was divided into irrigation at the beginning of jointing stage(J0)and irrigation at the 10 th day of jointing stage(J10),and the second irrigation time was divided into irrigation at the beginning of anther stage(F0)and irrigation at the 10 th day of anther stage(F10).There were 8 irrigation treatments in total.By exploring the effects of different irrigation combinations on soil water distribution,wheat growth and development characteristics,yield formation process,water consumption and water use efficiency of winter wheat,the high yield and water saving and efficient irrigation system of winter wheat was determined.The experimental results are as follows:(1)The effects of different irrigation combinations on soil moisture in wheat fields were expounded.Winter irrigation water can effectively increase the moisture content of 0-200 cm soil layer during the growth period of winter wheat,especially during the rise period.Spring irrigation mainly affected the soil moisture content of 0-80 cm soil layer in the root zone of wheat from heading to maturity stage.The combination of delayed irrigation jointing water and normal irrigation flowering water increased the soil water consumption in the root zone of wheat from filling to maturity stage,which could make full use of soil water storage and promote grain enrichment.Compared with J0,soil moisture content in 0-80 cm soil layer under J10 treatment decreased by 6.32% on average during wheat maturation stage.Compared with F0,the soil moisture content of 0-80 cm soil layer in F10 treatment increased by 15.05% on average.(2)The effects of different irrigation combinations on the growth and development of winter wheat were clarified.Overwintering water treatment increased plant height,leaf area index,above-ground dry matter accumulation,flag leaf chlorophyll content and relative content,net photosynthetic rate,transpiration rate and other physiological and ecological indexes of winter wheat.Compared with no overwintering water treatment,the maximum plant height,maximum leaf area index and final dry matter mass increased by 0.62%,7.88% and 13.11%,respectively.Delaying irrigation at jointing stage reduced the maximum leaf area index,but promoted plant height elongation,decreased the decline rate of flag leaf chlorophyll content,improved photosynthetic performance,and had higher dry matter accumulation.Compared with J0,the maximum plant height and final dry matter mass increased by 1.89% and 5.23%,respectively,and the maximum leaf area index decreased by 8.36%.Normal irrigation of flowering water had significant effects on physiological indexes of wheat flag leaves,which was conducive to maintaining relatively high net photosynthetic rate and chlorophyll activity,promoting the accumulation of photochemical organic matter,and thus increasing the accumulation of dry matter in the above-ground part.(3)The effects of different irrigation combinations on grain filling characteristics and yield of winter wheat were revealed.Overwinter water treatment had a significant effect on grain yield,spring irrigation had a very significant effect on grain yield,but the interaction of the two had no significant effect on grain yield.Compared with no overwintering water,irrigation overwintering water treatment extended the duration of wheat filling,increased the 1000-grain weight and grain yield by 2.80% on average.Delaying irrigation of jointing water for 10 days increased the grain filling rate,prolonged the filling duration,increase the 1000-grain weight,and increased grain yield by 5.05% on average.Normal irrigation of flowering water is beneficial to prolong the filling duration,increase the 1000-grain weight and grain yield.Under the two overwintering water treatment conditions,the highest grain yield in spring irrigation treatment was J10F0.(4)The effects of different irrigation combinations on water consumption and water use efficiency of winter wheat were clarified.Compared with no overwintering water irrigation,the water consumption of winter wheat treated with overwintering water increased significantly by15.68%,and water use efficiency decreased significantly by 11.18%.Compared with normal irrigation jointing water treatment,the water consumption of winter wheat was significantly increased by 3.67% after 10 d delay.The highest water consumption and water use efficiency in spring were J10F0 and J0F0 for overwintering water irrigation treatment,and J10F0 and J10F0 for no overwintering water irrigation.(5)In this study,MJ10F0 was the irrigation combination with the highest grain yield.The yield of NJ10F0 was not significantly different from that of MJ10F0,but irrigation water consumption was reduced by 33.33% and water use efficiency was increased by 9.37%.The irrigation combination with NJ0F0 had the highest water use efficiency of wheat,but its grain yield was significantly decreased by 6.56% compared with MJ10F0 treatment,and there was no significant difference in water use efficiency between NJ0F0 and NJ10F0 treatment.Comprehensive consideration of the growth and development,yield,irrigation amount,water consumption and water use efficiency of wheat in the experimental year,the high-yield,watersaving and high efficiency irrigation mode during the growth period of winter wheat in the experimental area was no overwinter water irrigation + irrigation at the 10 th day of jointing stage + irrigation at the beginning of flowering stage,and the irrigation water quota is 75 mm. |
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