Study On Influence Of Irrigation Timing And Quantity On Alfalfa Seed Yield

Through different irrigation treatments, we studied on the change of soil water and therelationships between one-year-Alfalfa growth, fructification, seed yield component, seedproduction and the change of soil water. Irrigation treatments were done during budding stageand pod stage. And three irrigation levels were designed: 75mm, 120mm, 180mm. Results showed that during Alfalfa growth stage to branching stage when the soil watercontent was relatively high, irrigation was not carried out. In the budding stage, Alfalfaneeded to be irrigated as the soil water content reduced at 50% of field capacity. Irrigationinfluenced the soil water content in 0-50 cm soil. Damp soil was increased with adding waterso 180mm water can saturate 70 cm soil. In the pod stage,the ratio of soil water loss waslessen. Alfalfa growth and fructification was influenced by the time and the quantity of irrigationand the time is important. When the irrigation was done at budding stage, alfalfa can flower,fertilization and pod in a centralized time. Pod stage irrigation did not much influence theheight of plant and growth speed but it caused the reproduction stage delayed and the moreabortive pods. The number of pods per plant, the number of pods per shoot and the number of pods perinflorescences had significance difference among different irrigation treatments. T7 wastreated by 180mm irrigation water at budding stage, which of the number of pods per plantwas the most: 103 pods per plant. Moreover, which seed yield of T7 was much more thanother treatments was 400.64Kg/hm2. The seed components of T7, such as the number of podsper plant, the number of pods per shoot , the number of pods per inflorescences and the seedproduction per plant was also much more than others. Irrigation-water use efficiency (WUEi) was increased by added water amount. For theequal amount the efficiency had relation with the time of irrigation. While it was at buddingstage WUEi was high. Under certain climate, the proper time of regulated deficit irrigation isin the pod stage for alfalfa..