Effects Of Aerated Irrigation At Different Growth Stages On Nitrogen Absorption And Transformation Of Processing Tomato Under Drip Irrigation

Object:Xinjiang is currently the largest processing tomato production area in China.The typical climate environment in Xinjiang is very suitable for the growth of processing tomatoes.At the same time,combined with the efficient drip irrigation planting mode under the film,it has promoted the rapid development of processing tomato industry in Xinjiang.At the same time,because the film mulching hinders the gas exchange between soil and air,destroys the dynamic balance system of soil O₂production and diffusion,and changes the water and heat conditions of soil,It intensifies the phenomenon of crop root zone hypoxia.Process tomato is one of the most sensitive crops to the lack of soil oxygen supply.Root zone hypoxia will affect root growth,hinder the absorption of water and fertilizer,and then inhibit the growth and development of plants and the formation of yield.The drip head is easy to be formed near the sub irrigation area due to lack of oxygen,but it is easy to form the drip head near the sub irrigation area.At the same time,crop root growth and development,root water and nutrient absorption and aboveground transportation are easy to have negative effects due to hypoxia in the root zone,which will affect crop metabolism and crop yield and quality.Aerated irrigation is developed on the basis of subsurface drip irrigation.It is an irrigation method that uses venturi aerating equipment to suck air into irrigation water to form water air mixture.The effects of aerated irrigation in different growth stages and under different nitrogen application rates on the growth and development of processing tomato fruit yield,irrigation water use efficiency,partial productivity of nitrogen fertilizer and fruit quality were studied.The experimental treatments were comprehensively evaluated by combined evaluation method,and the aerated irrigation mode suitable for the whole growth stage of subsurface drip irrigation Processing Tomato in Northern Xinjiang was selected.Methods:Two crop experiments were conducted in the Key Laboratory of modern water-saving irrigation,Shihezi University,Shihezi City,Xinjiang Uygur Autonomous Region,China from April 2019 to September 2019 and from April 2021 to September 2021.Two factors are set in the 2019 test.The amount of irrigation and the level of aeration;The irrigation volume is 4950 m³hm^-2（W1）,4750 m³hm^-2（W2）,4500 m³hm^-2（W3）,4050 m³hm^-2（W4）.Aerated irrigation is set at two aerated levels:0（A1）and 17%（A2）.The experiment was a two factor completely random design.In 2021,the experiment set two factors.Aerated irrigation in different growth stages and nitrogen application level:no aeration in the whole growth stage（A0）,aeration in the whole growth stage（A1）,aeration in the flowering stage（A2）and aeration in the fruit expansion stage（A3）.The nitrogen application rate is set at three levels:150 kg hm^-2（N1）,210 kg hm^-2（N2）and 270 kg hm^-2（N3）.The experiment was a two factor completely random design.Results:（1）Under the condition of aerated irrigation,the cumulative yield of processing tomato was 9.7%higher than that of conventional irrigation,and the yield per plant of A2W1,A2W2,A2W3 and A2W4treatments were 10.3%,9.9%,8.9%and 9.5%higher than that of conventional irrigation,respectively.IWUE is further increased on the basis of subsurface drip irrigation.The effect of aerated irrigation on processing tomato quality was better than conventional irrigation.The average Vc content and soluble solid content under A2W1,A2W2,A2W3 and A2W4 treatments increased by 4.0%and 4.4%respectively.（2）The plant height,stem diameter,net photosynthetic rate,stomatal conductance and transpiration rate of tomato treated with A1N2 were higher than those of other treatments.Aerated irrigation in the whole growth period and fruit expansion period can promote the improvement of the yield and quality of processing tomato,while aerated irrigation in flowering period has no significant change on the improvement of the yield and quality of processing tomato.（3）The combined treatment of aerated irrigation in different growth stages and different nitrogen application levels had a very significant effect on the total nitrogen content in stems,leaves and fruits of drip irrigation tomato（P<0.01）.In the combined treatment of aerated irrigation and different nitrogen application levels in different growth stages,the total nitrogen content in fruit was the highest,followed by leaf and stem.The total nitrogen content in fruit accounts for 45.5%～50.7%of the total nitrogen accumulation of processing tomato,the total nitrogen content in leaf accounts for 26.7%～30.1%of the total nitrogen accumulation of processing tomato,and the total nitrogen content in stem accounts for 22.2%～24.8%of the total nitrogen accumulation of processing tomato.（4）Based on the comprehensive analysis of the effects of different treatments on yield indexes（yield per plant,fruit number per plant and fruit weight）,water use efficiency and fruit quality indexes（Vc,soluble sugar,soluble solid,organic acid and sugar acid ratio）,the comprehensive scores of each treatment were obtained by comprehensive evaluation method.The treatment scores of aerated irrigation were higher than those of non-aerated irrigation.A2W2 is the first treatment in 2019 test and A1N2 is the first treatment in2021 test.Therefore,the aerated irrigation treatment with irrigation level of 4500 m³hm^-2and nitrogen application rate of 210 kg hm^-2can better take into account the triple objectives of high yield,water saving and high quality of processing tomato,and provide a theoretical basis for the practical application of aerated irrigation of processing tomato in Northern Xinjiang.Conclusion:According to the analysis results of fuzzy Borda comprehensive evaluation method,it is concluded that the combination of aerated irrigation and medium fertilizer treatment in the whole growth period and fruit expansion period can achieve the dual objectives of improving tomato yield and quality and improving irrigation water use efficiency,and provide some theoretical guidance for the planting mode of processed tomato in Northern Xinjiang.