Effects Of Regulated Deficit Irrigation On The Growth Physiological Characteristics And Water Use Efficiency Of Maize In Northwest Liaoning

The sandy soil area in the northwestern part of Liaoning Province has a dry climate,low total precipitation and uneven distribution over time.The soil is mainly composed of sand soil and poor water retention capacity,which seriously affects the production capacity of the main local crops.In order to alleviate the water shortage problem in the aeolian sandy soil area in northwestern Liaoning and improve the utilization rate of agricultural water resources,the corn production is guaranteed to be stable and the water use efficiency is improved.In this study,the sub-film drip irrigation technique was adopted in the Alxiang Desert Ecological Park in Zhangwu County,Liaoning Province.The corn was used as the research object.The method of measuring the pit was used to study the growth and physiological traits and dry matter of corn in the arid sandy soil area in northwestern Liaoning.Distribution and transfer,soil nitrate nitrogen content,corn yield,water demand,water use efficiency and quality.In2017 and 2018,three water deficit levels were set in the maize seedling,jointing and heading stages:mild?65%?70%?_??,moderate?55%?65%,?_??and severe?50%?65%,?_??,9 water deficit treatment,and set the appropriate soil moisture content?70%?80%,?_??for the whole growth period as a control.The mechanism of the effects of regulated deficit irrigation on the growth and physiological regulation of maize in different growth stages was revealed,and the water regulation standard for maize green yield in the aeolian sandy soil area in northwestern Liaoning was proposed.The results of the two-year trial show:?1?Regulated deficit irrigation at different growth stages has a significant impact on maize growth.The more severe the control of the underwater line,the more severe the inhibition of maize plant height and leaf area.Mild regulated deficit irrigation at seedling stage showed a certain lag in corn growth performance.After rewatering at jointing stage,the growth rate of maize plant height was 60.7%which was 17.8%higher than CK treatment.The rehydration at jointing stage had a compensatory effect on the growth of maize plant height.Regulated deficit irrigation at jointing stage had the greatest impact on maize plant height,decreasing by 14.69%to 32.4%.Regulated deficit irrigation at heading stage had little effect on plant height.?2?During the seedling stage,the SPAD value increased by 3.14%compared with CK during the filling stage;the net photosynthetic rate increased by 9.01%compared with CK;the transpiration rate increased by 9.43%compared with CK treatment.After the jointing stage,the chlorophyll relative value,net photosynthetic rate and transpiration rate were not much different from CK.It is conducive to the accumulation of photosynthetic products in corn during grain filling.?3?The dry matter accumulation and distribution of maize in different growth stages were different,and the distribution amount was spike>stem>leaf.Logistic model has a good linear relationship between the simulated and measured values of dry matter accumulation for two years,and R² was between 0.97 and 0.99?P<0.01?.Mild water lossed treatment during seedling and jointing can prolong the accumulation of dry matter and increase dry matter production.In the late growth stage,the dry matter accumulation after T1?seedling period,65%???and T4?jointing stage,65%???was 35.51 and 52.11 kg·hm^-2 higher than that of CK,respectively.The contribution rate of grain was 5.19%and 13.33%higher than that of CK treatment.?4?Regulated deficit irrigation at different growth stages reduced the ear length,ear diameter,ear weight,grain number per ear,and 100-grain weight of corn,and increased the length of corn abalone,which eventually led to a decrease in corn yield after regulated deficit irrigation.The severely regulated deficit irrigation treatment at each growth stage had the most obvious effect on yield reduction.The yield of severe regulated deficit irrigation in the seedling,jointing and heading stages decreased by 16.7%,19.35%and 19.75%,respectively.Although the yield of T1 was 3.74%lower than that of CK,the difference was not significant.?5?Regulated deficit irrigation can reduce the water consumption of corn during the whole growth period and increase the water use efficiency of crops,but also reduce the yield of corn.At 2017 and 2018,the water use efficiency of maize under mild drought-regulated irrigation was the highest,2.06 kg·m^-3 and 2.24 kg·m^-3,respectively.The TOPSIS method based on entropy weight with two-year data,the comprehensive benefits of maize under T1?seedling period,65%???and T4?jointing stage,65%???were the best.The resulted showed that mild regulated deficit irrigation?65%???at the seedling stage and mild regulated deficit irrigation?65%???at the jointing stage reduced the plant height and leaf area of the maize,and reduced the corn.The vegetative growth,but promoted the reproductive growth of corn.The photosynthesis rate and transpiration rate of maize during grain filling period were improved,which was beneficial to the distribution of photosynthetic producting to corn ear,reducing crop water consumption,improving water use efficiency,ensuring stable yield of corn,and realizing corn planting and water saving in stable wind and sand area in northwestern Liaoning.the goal of upgrading quality.