Study On Deficit Irrigation Schedule For Maize Under Agronomic Management

This research was based on the climate condition of WuWei City and district border irrigation planting model, JingSui NO.1 of spring maize was the test crop. By designing straw cover and film mulching, four irrigation treatments, this paper analyzed the different irrigation schedules under different covering ways influenced to soil temperature, soil water content, water consumption, biological characteristics, yield and water use efficiency, and worked out the water production function of spring maize, and the original irrigation schedule has been optimized. The research conclusions were as follows:(1) Film mulching had positive effect to soil content and soil temperature, which made seedling emergence early and shortened the growth stage of spring maize, and comparing to straw cover and bare land, seedling emergence was early 15 days and 7 days respectively. Straw cover had good cooling and bufferaction in lately growth stage of spring maize, which can delay the root senescence and prolong the growth stage.(2) The height of spring maize and spike height were increasing with the growth of spring maize and the irrigation amount. The height of spring maize under straw covering was relatively large, and the spike height under film mulching was relatively high. The effect of covering on the leaf area was great different in the earlier stage of spring maize, and little difference in the later stage. The maximum value of dry matter weights underground by film mulching appeared at the heading stage, and by straw covering was at the filling stage. The relationship between individual biomass and time was an unconspicuous S-type curve.(3) The effect of covering ways on yield component factors were different, and the difference of the effect on yield was significant (P<0.05). The effect of each irrigation treatments on yield and yield component factors were significant(P<0.05). The effect of grain number per spike by film mulching on yield was the minimum. The effect of spike length, grains per spike and kernels per row under straw covering on yield were less. Film mulching more improves the yield than straw covering.(4) The soil water content increased with the increasing of irrigation amount, however, the irrigation water was greatiy effected in the depth of 20~80cm, and the difference of irrigation water was the most obviously. The difference of soil content among different treatments in 0~20cm was no significant, and in 80~120cm was basically keep steady.(5) The soil evaporation was mainly controled by the surface soil water, the proportion of the soil evaporation account to the total evapotranspiration quantity changed with the growth of spring maize and the soil water content, and the trend was big-small-big. Straw covering was more beneficial to reduce ineffective evaporation. In the growth stage, the soil evaporation became small with the increased leaf area index. E and LAI under the surface soil humid condition has good relativity. There was a linear correlation between the change trend of total evapotranspiration quantity of spring maize and the change trend of soil content in depth of 0~60cm .(6) The total water consumption of spring maize in the whole growth stage increased with the increasing of irrigation quota. And the water consumption intensity of each treatment was a bimodal curve, the two peak were from seedling stage to jointing stage and heading stage to filling stage respectively. Meanwhile, water stress impeled the peak of water consumption in different treatments.(7) The relationship between water consumption and yield was a quadratic parabola, through solving stage water production function by using Jensen model, we got that the critical period of water requirement of spring maize bu straw covering was at heading stage, and that by film mulching was before heading stage.(8) The high efficient water use irrigation quota of spring maize by film mulching was 653.19mm, which has a higher economic benefit. The treatment f3 was recommended as the optimal irrigation planting pattern, which meet the water requirement of spring maize from jointing stage to heading stage, meanwhile, can properly reduce irrigation water before jointing and after wax mature.