| The Guanzhong Plain is a typical irrigated area located in the middle of Shaanxi Province,the main area for winter wheat production within northwestern China.The intensification of conflicts in water use has seriously decreased the yield of winter wheat on the plain,restricting the efficient and sustainable development of agriculture.Irrigation can alleviate the impact of drought on winter wheat yield,but the use of surface irrigation methods and excessive water consumption in agricultural production translate to especially low water-use efficiency(WUE)in northwestern China.The activation treatment of irrigation water(magnetization,oxidation and their mutual coupling treatment)has improved the activity of irrigation water and the physiological characteristics of some crops.But the regulation effects of increasing production and promoting WUE remain unclear,which limits the promotion and application in agricultural production.Based on the current situation that the yield of winter wheat in Guanzhong Plain is restrained and the WUE is low,and the activated treatment of irrigation water can increase the activity of irrigation water and promote the growth of crops.Therefore,it is necessary to deepen the research on the application of activated water and clarify the action mechanism of activated water on the growth,yield and WUE,which provides a new way to ensure the stability yield and improve water-use efficiency of winter wheat.During 2018-2020,the determination of physicochemical properties of activated water and infiltration experiment,hydroponic and field irrigation experiment of winter wheat were carried out in the greenhouse and Caoxinzhuang experimental farm of Northwest Agricultural and Forestry University.The objective of this study was to:(1)analyze and compare the variation distinctions and maintenance time of physicochemical properties of groundwater and brackish water after activation treatment,and clarify the infiltration characteristics of activated water in the soil and the transport regular of accompanying water and salt,(2)explore the effects of hydroponics and field irrigation water activation treatments on the physiological growth characteristics of wheat,(3)measure and quantify soil water under different irrigation treatments,(4)discuss and evaluate the relationship between the yield and water-use efficiency of wheat with different irrigation amount and irrigation water activation methods.The main conclusions of this research are as follows:(1)Groundwater and brackish water were used as raw water for activation treatment(magnetization,oxidation and their sequential coupling).It was found that the p H value and dissolved oxygen concentration of the groundwater and brackish water activation treatment increased,while the surface tension and viscosity coefficient decreased.The surface tension of groundwater after magnetization and oxidation treatment decreased by 15.4%and 7.4%,respectively,and the difference before and after magnetization treatment was significant(P<0.05).The effects of different activation treatments on the surface tension and viscosity coefficient of groundwater and brackish water gradually disappeared after 10 h and 2 h,respectively.The generation of·OH(an important active oxygen)in magnetized water and oxidized water directly proved that the oxidation ability of groundwater by magnetization and oxidation treatment was enhanced,which was the improvement of activity.The cumulative infiltration amount of magnetization and oxidation treatment of groundwater at100 min were significantly reduced by 89.3%and 153.6%,compared with groundwater(P<0.05).Moreover,the infiltration rate of groundwater and brackish water decreased after activation treatment,and the wetting front depth(at 100 min)of groundwater after magnetization and oxidation treatment was significantly lower than that of groundwater by49.2%and 59.1%,respectively(P<0.05).At the end of infiltration,the average soil salt content at the wetting front of magnetized water and oxidized water was 13.3%and 37.8%higher than that of untreated groundwater,respectively,and the effect of oxidation treatment was more significant(P<0.05).(2)Soaking seeds in groundwater and brackish water after activation treatment could increase the germination rate by 24.8-78.9%and 20.9-10.9%,respectively.The results showed that the germination rate of wheat treated by magnetization and oxidation significantly increased by 24.8%and 31.1%,respectively(P<0.05).The leaf chlorophyll content of wheat cultivated in groundwater and brackish water after activation treatment increased by 12.6-25.9%and 13.1-22.5%,respectively.The effect of magnetization was similar to that of oxidation treatment,and the chlorophyll content was significantly increased by 26.1%and 26.8%,respectively,compared with untreated groundwater(P<0.05).The root vigor of wheat cultivated in groundwater treated with magnetization,oxidation and the combination of magnetization and oxidation significantly increased by 101.2%,253.7%,100.5%and 166.3%,respectively(P<0.05).The root weight density of wheat with groundwater by activation treatment was increased by 25.1-75.8%.The magnetization and oxidation treatment enhanced the root length density by 67.6%and 79.4%,respectively.The field irrigation experiment showed that the net photosynthetic rate of leaves during the filling stage under the treatments of magnetization,oxidation and the combination of magnetization and oxidation increased by 15.1%,18.9%,14.3%and 14.9%,respectively,compared with groundwater irrigation.In addition,magnetized water and oxidized water irrigation could increase the root length density and root weight density of winter wheat in 0-20 cm soil layer at flowering stage by 22.7%and 24.0%,9.8%and 26.0%,respectively.(3)The soil-water content in 0-100 cm soil layer in the winter wheat growing season fluctuated greatly under the influence of irrigation.The average soil-water content of the0-100 cm soil layer under groundwater irrigation 180 mm was 18.2%higher than that of the control(irrigation amount was 0 mm).The average soil-water content of the 0-100 cm soil layer under the irrigation of magnetized water and oxidized water was decreased by 4.3%and 8.4%,respectively,compared with groundwater irrigation.The average soil-water content of 120 mm and 180 mm magnetized irrigation treatments in 0-100 cm soil layer increased by 7.6%and 15.0%,respectively,compared with irrigation 60 mm.The soil-water storage of 0-100 cm soil layer at the jointing stage under the magnetized water and oxidized water irrigation was decreased by 6.2%and 9.3%,respectively,compared with groundwater irrigation.Under the treatment of magnetization and oxidation,the soil-water storage in0-100 cm profiles at the mature stage of winter wheat was reduced by 1.7%and 8.1%,while soil available water storage during the greening-maturing period of winter wheat significantly increased by 61.1%and 66.7%(P<0.05),respectively,compared with groundwater irrigation.During 2019-2020,the soil available water storage(from greening to mature stage)of 0-100 cm profiles of groundwater,magnetized water and oxidized water irrigation reduced by 49 mm,34 mm and 42 mm,respectively.(4)In the growing season of winter wheat in 2018-2019,the grain number per spike of the irrigation treatment was 8.1-21.0%higher than that of control(irrigation amount was 0mm).Under the same irrigation amount,the grain number per spike of irrigation with activated water was 2.1-7.3%higher than that of groundwater irrigation.When the total irrigation amount was 120 mm,the 1000-grain weight was increased by 5.9%compared with the total irrigation amount of 60 mm,but the 1000-grain weight reduced when the irrigation amount was 180 mm.The grain yield of winter wheat by irrigation of magnetized water and oxidation water increased by 21.0%and 11.1%,respectively,but the difference has not reached a significant level(P>0.05).During 2019-2020,the water-use efficiency of magnetized water and oxidized water irrigation increased by 21.0%and 13.8%,respectively,compared with groundwater irrigation,and there was significant difference between magnetized water irrigation and groundwater irrigation(P<0.05).The water productivity of the magnetized water and oxidized water irrigation during sowing to jointing stage increased by 16.2%and 6.0%,respectively,compared with groundwater irrigation.The irrigation water use efficiency under the 120 mm and 180 mm treatments of oxidized water irrigation were64.9%and 66.7%lower than that of the 60 mm irrigation treatment,respectively.The average grain yield and WUE were 11.47×103 kg ha-1and 10.56×103 kg ha-1,27.45 kg ha-1mm-1and 25.81 kg ha-1 mm-1,respectively,when magnetized water and oxidized water irrigation with the total irrigation amount was 120 mm in the growing season of winter wheat from 2018 to 2020.According to the relationship equations between grain yield and WUE of winter wheat with irrigation amount,it could be concluded that the average irrigation amount of 116 mm in the growing season of winter wheat in Guanzhong Plain was the most favorable to obtain grain yield and improve water-use efficiency. |
PDF Full Text Request