Interactive Effects Of Water And Nitrogen Under Drip Fertigation And Simulation Growth Of Maize In Hetao Irrigation District

There is a seriously lacking in theoretical basis and application in technical support by application with drip irrigation under mulch in the currently croping of system in hetao irrigation area.There are lots of study in developing irrigation system and the mulching effect in the technology of drip irrigation of water and fertilization integrality in hetao irrigation area,however,the mutual effect between water and fertilizer and the water-fertilizer optimum management have not been mentioned.Based on discussion above,the study is taking corn under mulching drip irrigation for an example,combained field experiment and CERES-Maize model,analyse the growth and development process,water and nitrogen use efficiency,soil-corn nitrogen balance and water and nitrogen optimize combination of maize in different hydrologic year under the condition of water and fertilizer integration with drip irrigation.Put forward the technical measures of optimizing management of water and nitrogen with drip irrigation,and provide theoretical foundation of popularization and application.1.There are notable interaction of water and nitrogen to maize grain yield under the effect of water and nitrogen interactions with drip irrigation.Appropriate water and nitrogen treatment can obtain higher grain yield by improving the line number,enhancing hundred-grain weight.But it is limited in gaining good harvest through boosting hundred-grain in consideration of maize hereditary character So,try hard to increase line number is an effective way to improve corn yield in the process of corn production in hetao irrigation.2.Pearson correlation analysis among corn birth index shows that there are extremely positive correlation between corn LAI,dry substance mass,relative chlorophyll content and the grain yield.Canonical correlation analysis results shows that increasing plant height can contribute to the grain yield while the too high corn LAI and dry substance mass can lead to reduction of output.Grey relational analysis indicate the high relevance of corn LAI and overground part dry substance with yield,which might relate to the photosynthetic rate date which is at the stage of waxy corn.3.The results of the Richards growth equation fitting show that:Irrigation mainly increased the leaf area index by increasing the growth rate of LAI,increased plant height by prolonging the growth period of plant height,and affected the accumulation of dry matter by affecting the accumulation rate of maize biomass.Fertilizer nitrogen can increased the leaf area index by adjusting the accumulated temperature and growth rate of LAI.The plant height was increased by adjusting the accumulated temperature of plant height,and the accumulation of dry matter was affected by the number of days affecting the growth period of maize.In addition,increasing the active period of maize plant height growth can increase the 100-grain weight,and increase the number of corn ear rows to improve grain yield.Increasing the maximum dry matter mass and the active phase of dry matter growth can increase the number of rows and grains,thereby increasing the final grain yield.The influence factors of the maximum yield were as follows:maximum maize LAI value and plant height growth period,in which the effect of maximum LAI on yield was less than that of plant height growth.4.The fuzzy comprehensive evaluation of nitrogen uptake of maize plants by water and nitrogen interaction showed that W3N4 treatment index was the largest.However,Excessive plant nitrogen uptake will have a negative effects on maize grain yield.So due to the corn grain yield and yield components of the fuzzy comprehensive evaluation.Combined the results of fuzzy evaluation and nitrogen use efficiency under different treatments.Choose the W2N3 treatment,control soil martic potential at-20kPa and the amount of nitrogen applied was 262.5 kg/hm2,as the optimal combination of water and nitrogen in drip fertigation under local maize production.5.The CERES-Maize model was used to study the management system of irrigation amounts and nitrogen fertilizer amounts under drip irrigation in different hydrological years.The maize yield and nitrogen use efficiency under different treatments was used as the evaluation index.In the rich water year,the optimal combination of irrigation water and nitrogen was control the lower limit of irrigation level at-30kPa and nitrogen fertilizer amounts is 260kg/hm2.In the normal year and dry year,the optimal combination of irrigation water and nitrogen was control the lower limit of irrigation level at-20kPa and nitrogen fertilizer amounts is 260kg/hm~2.