| This experiment was carried on in the different places in 2004-2006.A study on field water consumption law and water use efficiency of winter wheat and summer corn by field trial and controlled trial under a rainshelter was conducted,the result as follows:1 Annual soil-water dynamics change and water consumption law was researched on winter wheat and summer corn in a yearAnnual soil-water dynamics change and water consumption law on winter wheat and summer corn in a year were studied based on field trial and lysimeter trial under a rainshelter.The result showed that,the annual soil-water dynamics change in the continuous cropping on a plot between winter wheat and summer corn can be divided into three stages.They are slow consumption stage,rapid consumption stage and water supplement stage.In the whole growth stage,soil moisture was obviously different in vertical changes.For instance,in the layer of 0-20 cm,due to the sensitivity of the irrigation and rainfall,the changes of soil moisture was violently;in 20-60cm,it was relatively smaller;in 60-100 cm,soil moisture was most stable.The soil water in the winter wheat season hardly had an effect for summer corn growth,but the deposited soil water in the summer corn growthing period played an important role in later effect for the winter wheat growth.By researching the daily water consumption and modular coefficient,the critical period of water requirement of winter wheat was for the booting stage to florescence and the critical period of water requirement of summer corn was about 40 days before and after tasseling-anthesis stage.2 The effect of different water supply conditions on growth and physiological characters of winter wheat and summer corn.Soil water deficit on the effects of irrigation at different growth stages growth and development and physiological characteristics of winter wheat and summer corn.The results showed that,the adequate period and amount of winter wheat irrigation was favourable to the dry matter accumulation,but water sufficient was not propitious to dry matter transfer from stem and leaf to sheath and spike,late irrigation was propitious to increase the amount of dry matter transporting to the sheath and spike.In a certain range with the increase in the amount of irrigation,leaf area index increased.Water deficit had adverse impact on growth of summer corn,its leaf area,plant height was lower than that of order water treatment,especially drought at jointing stage and tasseling-anthesis stage.Adequate moisture in late winter wheat grain-filling stage made flag leaf for a longer period to maintain high photosynthetic rate,and transpiration rate,higher stomata conductance,higher leaf water potential and lower canopy temperature,But leaf soluble sugar content reduced,and appropriate irrigation had higher Fv/Fm and Fv/Fo,Chlorophyll in flag leaf increased.Winter wheat and summer corn suffering from water stress,had a series of reactions,which was reflected in that leaf water potential, photosynthesis,transpiration rate and stomata conductance decreased.Physiological signals were affected by the intensity and duration of water deficit.Various physiological indicators have obvious diurnal variation.In fine weather conditions,the trend of the photosynthetic rate,transpiration rate changes was essentially consistent,all began to rise after7:00,photosynthetic rate peak occurred earlier than the transpiration rate,photosynthesis and transpiration rate of the maximum value was in between 10:00 and 14:00,then decreased a gradually,but the change of stomata conductance was not quite the same as the photosynthetic rate,its maximum value occurred at about 10:00.3 The effect of different water supply conditions on yield and quality of winter wheat and summer cornIrrigation obviously increased the yield and yield character,with the irrigation quantity increase wheat yield improved;irrigation at re-greening stage and before winter period increased the wheat ears,irrigation at jointing stage and booting stage obviously improved wheat grains and irrigation at heading stage affected 1000-grain weight.Summer corn yield increased with irrigation and the effect of irrigation at later stage was higher than reproductive effects of irrigation later than early irrigation that at early stage.The water deficit in each stage of winter wheat effectively reduced the number of spikes,drought at the jointing and booting stage mainly reduced the valid ears,grains,and increased invalid ears,drought at filling-grain stage mainly affected grains and 1000-grain weight,with the extent of drought,1000-grain weight significantly reduced;Drought at Seedling stage had less effect on vavious traits. Drought occurred at different growth stages of summer corn had shorter ear length, longer bald length,smallerear diameter,reduced the number of row and 1000-grain weight,and the more severe drought was,the greater impact;Drought at tasselling stage influenced greatly the ear length,Bald length,ear diameter and raw number and output reduced most,drought at jointing stage followed,drought at seedling had the smallest impact;drought at filling stage had a greatest impact on 1000-grain weight,next drought at tasseling-anthesis stag.Soil moisture had important implications to physical chemical properties of grain. Test results showed that:With the irrigation times increase,wheat grain density and falling number gradually declined,theological parameters performed better,tensile parameters expressed poorly.From the irrigation period,jointing stage and heading stage for irrigation,improved the rheological parameters and tensile instrument parameters,But reduced grain density and falling number;irrigation at booting stage can increase grain density and falling number,But was unfavourable for dough development time and stability time.From the test results of summer corn,drought had adverse effects on starch content and improved the crude protein,fat and lysine content.4 Water use efficiency and the optimal allocation of limited waterIrrigation could increase the water use efficiency of single leaf at forenoon,but reduced leaf water use efficiency at afternoon;WUE of population level increased with field water consumption increasing,variety trend assumed quadratic,when up to a certain value of water consumption,the WUE of population level started to decline. During the growth of winter wheat,irrigation significantly reduced water use efficiency, but clearly increased water use efficiency of maize.From the effect of drought at different periods on winter wheat and summer corn yield respectively,the relationship between winter wheat or summer corn production and water consumption was good second parabolic curve.Output coefficients and Jensen model were used to analyze the relationship between crop yield and water consumption,water production function model that showed the relationship between winter wheat or summer corn yield and water consumption was established.Yield reduce coefficient and sensitive index water deficit of for winter wheat and summer corn were obtained,thus it can be seen that the key stages of winter wheat were from jointing stage to heading stage and heading stage to filling stage,the key stage of summer corn was from jointing stage to filling stage. |
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