Regulating And Controlling Mechanism Of Regulated Deficit Irrigation And Nutrient Regulation On Yield And Quality Of Wheat

How the soil moisture and nutrients work together to realize the high-yield,high-quality and efficient of winter wheat,which has become a hot research topic today.In order to ensure the needs of national food security,and sustainable development of soil,the regulation effects of Regulated deficit irrigation(RDI)and nutrient regulation on the yield and quality formation of winter wheat was carried out in areas with insufficient water resources such as the Huanghuaihai Plain.This research has an important theoretical and practical significance.In this paper,winter wheat(Triticum aestivam L.)was used as experimental materials.Different treatments of different water deficits and fertilizers were set up under a rain-shelter and field,and a series of plots and field trials such as potting,tube planting and lysimeters experiment,were conducted with the advanced equipment.The main research contents include:1)the effects of regulated deficit irrigation on the growth and physiological characteristics of winter wheat;2)the effects of regulated deficit irrigation and nutrient regulation on yield and quality characteristics of winter wheat;3)effects of water and nutrient synergy on nitrogen uptake and utilization as well as dry matter translocation of winter wheat;4)establishing the mathematical model for optimized combination of regulated deficit irrigation and nutrient regulation;and 5)the simulation of soil temperature and water consumption of winter wheat and summer maize.Through conducting above research contents,the following conclusions can be drawn:1.Alternate furrow irrigation and regulated deficit irrigation of alternate furrows reduced the photosynthesis of flag leaves to some extent,but the higher leaf water use efficiency could ensure the gain-filling process to the greatest extent,so that the yield did not reduced greatly.Under the condition of sufficient soil moisture before wheat seeding,appropriate water stress in the returning green-jointing period did not cause a significant reduction in grain yield and could significantly increase water use efficiency(WUE).Therefore,from the perspective of water saving and high efficiency,it is feasible to combine regulated deficit irrigation and alternate furrow irrigation.The soil moisture of 55%-65%field capacity(FC)during the returning green-jointing period is the right choice for water conservation and food guarantee under the regulated deficit irrigation of alternate furrows.2.The effect of RDI combining with nutrient regulation on the metabolism of C and N in winter wheat plants showed that under high nutrient levels,moderate water deficit regulation could promote pre-flowering storage substance of wheat vegetative organs re-transport to grains.Under the moderate nutrient level,the re-translocation amount of storage assimilates pre-flowering was the highest with mild water deficient.At a low nutrient level,the re-translocation amount and re-translocation rate of pre-flowering storage assimilates of various vegetative organs increased with water deficit.Under different nutrient levels,the contribution rate of total translocation of storage assimilates in vegetative organs to grain yield increased with the intensity of water deficit.It indicated that regulated water deficit increased the ratio of the storage material from the pre-flowering vegetative organs to grains.The results of 15N labeling study showed that the combination of water deficit regulation and nutrient regulation could effectively regulate the absorption and accumulation of fertilizer nitrogen by wheat plants.3.The effects of regulated deficit irrigation and nutrient regulation on grain yield and quality characteristics of medium and strong gluten wheat showed that light water deficit during returning green-jointing stage and grain filling stage did not affected grain yield obviously,but significantly improved WUE.The grain yield loss showed an increasing trend with the increase of water deficit.Water deficit regulation at returning green and jointing stage reduced the content of essential amino acid,proline,tyrosine,amino acid and protein in wheat grains,and the decrease intensity of the content increased with water deficit.However,water deficit regulation at jointing-heading stage significantly increased the content of essential amino acid,proline,total amino acid and protein in wheat grains.Severe water deficit during grain filling period increased significantly the content of amino acid,proline,tyrosine,total amino acid,and protein content,as well as falling number in wheat grains,while the mild and moderate water deficit had an insignificant effect on protein content of wheat grain.4.According to data from the four-factor and five-level combination design,three mathematical models with the objective function of yield,quality and water use efficiency were established respectively,and the multi-objective joint simulation of the model was optimized to obtain the optimization program for water-saving,high-yield and high quality with RDI combined with nutrient regulation under different decision targets.5.The soil heat flow equation was improved by means of coordinate transformation.The simulation result of improved soil heat flow equation was much closer to the actual value of soil temperature.The simulation equation of water requirement process in winter wheat was established based on the comprehensive factors of meteorology,biology and soil.6.With the help of ridge planting and furrow irrigation method,this paper integrated the theory and technology of Regulated Irrigation Deficit(RDI)and Alternate Furrow Irrigation(AFI).Using the ideas and methods of system engineering,we not only consider the time(growth period)of water regulation,but also consider the space(root zone)of water regulation so as to seek for the interaction mechanism and synergistic effect with the space and time of water control,thus a new non-full irrigation implementation technology,namely Spatial-temporal Regulated Irrigation(STRI)with water saving high yield,high quality and high efficiency has been created.The suitable technical elements included:1)specifications of ridge and furrow were that the ridge height was 20cm,ridge width was 50cm,the bottom width of ditch was 20cm,the top width of ditch was 60cm,and the slope was 1:1;2)in the ridge planting winter wheat,three rows of winter wheat were planted on one ridge with 15cm row spacing;and 3)light water deficit(55%-65%FC)at returning green-jointing stage of winter wheat and at seedling stage of summer maize could be implemented,and alternate furrow irrigation was adopted at other growth stages of crops.The experiment and demonstration results show that spatial-temporal regulated irrigation technology in farmland can achieve the goal of improving irrigation water efficiency and farmland water use efficiency.This research results have an important scientific and practical significance to establish the comprehensive indicators and models of RDI for optimizing the relationship between crop yield and quality,to enrich and perfect RDI theory,as well as to deepen and enrich the physiological and biochemical basic research of crop quality.