| As the world’s population increases, water resources for agriculture become more restrictive and efficient water use takes on greater importance. In2012-2013experiment, Irrigation treatments were (II):Irrigation before sowing (60Liter),(12):Irrigation before sowing (30Liter)+before freezing (30Liter);(13):Irrigation before sowing (30Liter)+before freezing (30Liter)+Irrigation in the beginning of erecting stage (60Liter)+Irrigation at flowering stage (60Liter);(14):Irrigation before sowing (30Liter)+Irrigation before freezing (30Liter)+Irrigation at the booting stage (60Liter)+Irrigation at flowering stage (60Liter). The weighing lysimeter system is located in National Precision Agriculture Demonstration Station in Xiaotangshang Town of Beijing. The maximum and the minimum LAI was achieved in13(5.96), and11(5.25), which had meaningful difference with each other (P<0.05). Both of the mentioned irrigation treatments had not significant differences with12and14(P>0.05). The highest final plant height was achieved in13(69.40cm), followed by14,11and12. The highest grain yield, harvest index, potassium percentage and ash percentage of forage wheat at flowering stage was obtained by14. The maximum total biological yield, forage protein percentage, seed phosphorus percentage and seed potassium percentage was related to13, but it had no significant differences with14(P>0.05). The maximum and the minimum grain yield was obtained by14(4.86t/ha), and11(2.87t/ha), which had significant differences with each other. The difference between11and12was not meaningful.13also had not significant difference with14, but, not only13, but also14had significant differences with11and12. The higher a thousand seed weight was obtained by14(34.85g), followed by13(31.93g),12(30.33g), and11(28.76g).14had significant difference with11, but there was not any meaningful difference between14and12and13. All differences among11,12and13were not meaningful. The maximum and the minimum number of seed per spike was related to13(22.75) and11(17.98), which had significant difference with each other. The results from the study indicate that irrigation winter wheat throughout the booting stage and flowering stage increased grain yield, harvest index, potassium percentage, ash percentage of forage wheat at flowering stage, seed and forage protein percentage. Therefore it is important to irrigate winter wheat throughout the booting stage and flowering stage in order to achieve higher yield. In all figures, from October to June, evapotranspiration trends increased steadily, especially in last four months, in which the lysimeter fields were covered by winter wheat completely. The highest total dry matter, was obtained for14in smaller lysimeter. Determination of coefficient for a thousand seed weight and mean evapotranspiration in April and May was0.858, and0.850, respectively. The maximum evapotranspiration value in March, April and May was obtained for lysimeter10(12)(558.70kg), lysimeter11(13)(467.25kg), and lysimeter10(12)(488.68kg), respectively. Knowledge about changes of soil water changes during successive growing seasons from planting to final ripening is a necessary tool for an effective planning of irrigation programs, in order to improve both quality and quantity of crop. In2013-2014experiment, Irrigation treatments were (II) no irrigantion,(12) irrigation only at jointing stage(60L),(13) irrigation at jointing(60L) and flowering stage(60L),(14) irrigation at jointing stage (April8th,60L),100%flowering stage (April30th,60L), and grain filling period (May lOth,6OL). The highest spike number per lysimeter was related to full irrigation (14), but it had no significant differences with other treatments (P>0.05).14had obtained the highest grain yield which was7.55ton/ha.14had no meaningful differences with13(P>0.05), but both13and14had significant differences with11and12(P<0.05). Grain yield in11and12was4.49ton/ha and4.65ton/ha, respectively. The maximum and the minimum harvest index was related to14(44.79%) and12(37.97%), which had significant differences with each other (P0.05). Harvest index in13was42.84%. Both irrigation and rainfall increased KC and after that it decreased gradually. Before irrigation KC was low and exactly after irrigation, it increased and then it decreased gradually day by day.R2between evapotranspiration which is on the basis of hourly weather data and daily weather data with measured ET in big lysimter was0.962and0.953, respectively. Evapotranspiration and crop coefficient almost exactly match according to R2of the regression. In conclusion, evapotranspiration and KC give a closer idea of the value of research on relationship between evapotranspiration and crop coefficient. |
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