Experimental Study On Water Consumption Rule And Water Use Efficiency Of Maize Under Regulated Deficit Irrigation Model

Because of the spatial and temporal cross-distribution state of water resources in Heilongjiang Province, combined with seasonal droughts, the development of agricultural production was limited and influenced. Contrapose the natural resources and disastrous situation of Heilongjiang Province, the pots experiments on regulated deficit irrigation were conducted in Beian Red Star Farm of Heilongjiang Province in 2013. By using contrastive analysis, statistic analysis, and model optimization algorithm, they analyzed the influence of maize’s biological properties, water consumption and yield caused by water deficit treatment. They also optimized and analyzed the different processing modes of regulated deficit irrigation, in order to save agricultural water and provide theoretical basis for high yield of maize in black soil region. The preliminary conclusions were as follows:(1) Being watered again, the height of maize will recover differently, the higher level of regulated deficit irrigation processing, the bigger degree of compensative growth during the single parenthood period. But re-watering had little effect on the plant height during filling period, the stem diameter during tasseling period affected by the degree of water deficit was relatively large. The light water deficit at seedling stage would lead the shortest length of barren ear tip. However, the length was relatively larger during tasseling period. The 100-grain weight at jointing stage was less than other single-regulated deficit growth stages, the root weights of mild regulated deficit growth were small at single parenthood stage, the root-shoot ratio at tasseling stage was maximum.(2) The growth indexes were the worst under the serious water deficit at the whole growth stage regulated deficit irrigation. During that period, the plant was short, the length of barren ear tip was the highest, and the yield was lowest. Therefore, the serious water deficit treatment was not suitable for crop at growth stage.(3) During different growth stages, there were different water requirements for maize. Among those, the water consumption was the largest during seedling growth period and the smallest during seeding period, and the water consumption was most sensitive during tasseling period. The water consumption was the largest during the single parenthood period with light water deficit. During the whole growth stage, provided with sufficient irrigation, water consumption would be 44.04kg/pot. The total water consumption was the highest at the jointing stage, followed was the tasseling stage, the proportion were 37.73% and 31.75% respective. When the maize was in the jointing and tasseling stage, the normal irrigation was needed, in order to meet their normal needs of water requirements.(4) During tasseling stage, the yield was influenced largely under serious water deficit condition. But the yield was not obviously influenced by water deficit at seeding stage. The yield was dropped obviously because of the water deficit at filling stage and elongation stage. When the water deficit treatment was below 60% of field water, the final maize yield would be influenced greatly.(5) At whole growth stage, water use efficiency was almost same between the suitable irrigation treatment and the sufficient irrigation treatment. They were 4.67g/kg and 4.63g/kg relative. The water use efficiency could be increased at seeding stage under medium water deficit condition. Compared with the normal irrigation treatment, water use efficiency of every treatment had no significant changes under the filling stage.(6) Analyzed from the whole growth stage, we found that the relationship between yield and total water consumption could be described with a quadratic parabola. When irrigation water was 46.93kg/pot, yield was the highest with the number of 206.98 g/pot. Jensen water production function model was established. Water consumption and yield data were fitted during the whole growth period, so as to obtain the sensitivity indexes at different growth stages, and the sequence from high to low was: tasseling stage, jointing stage, filling stage and seeding stage.(7) The projection pursuit model based on real-code accelerating genetic algorithm(RAGA) was established in order to analyze the different regulated deficit irrigation in the experiment. According to the results, they found that the best regulated deficit irrigation scheme is to keep the water at 60% of the field capacity during seeding period. Compared with the normal irrigation treatment, the yield and the water use efficiency were increased by 2.11% and 6.42% respectively.