Research On Key Time Of Water Supplement Of Typical Artificial Grassland Of Inner Mongolia Xilinhaote City

Combining two-year sampling observation (2013-2014) about typical artificial grassland of Inner Mongolia Xilinhaote city, the survey investigated on varation of soil moisture, plant growing situation and biological forage yield according to different irrigation treatment. According to integrated analysis towards different growth indexes, the experiment therefore determine the best irrigation frequency and water supplying period of various forage grasses, in order to provide a scientific basis for determining a better water-saving irrigation system, and to improve the economic benefits of forage grasses of high yield and efficiency.The main conclusions are following:1、During the budding period (5-6 months), surface soil evaporation is faster and water loses quickly, irrigation is needed, and will mainly affect the fluctuation of the irrigation of shallow soil; during the flowering period (mainly July), the rainfall will reduce the evaporation, soil moisture can be maintained at a certain level, therefore the irrigation cannot play a key role; during the podding period (mainly August), deep soil can maintain a relatively high humidity, while the forage yield decreased, therefore, irrigation during that time will be of little significance.2、The experiment started from May and ended in August, measuring the sample every half a month. During the flowering period (late in July), as all irrigation treatments and all kinds of forage grasses yield reached the maximum value, irrigation after that period will not significantly increase the forage yield of that year.3、For Bromus inermis and Agropyron cristatum, irrigation during early in growth season (5-6 months) is the key time to maintain a larger plant growth, and is conducive to form a relatively steady and high forage yield. During this time, irrigation for once, the plant utilization rate will be relatively high and the production efficiency reaches the peak. The irrigation amount during that time was 52.5mm.4、As to Medicago sativa, due to its characteristics of low water usage efficiency and high water consumption, high yield can be obtained when the water is sufficient, so during the whole growing season, irrigation should be conducted for 3-4 times to ensure the adequate moisture and stable growth of grass.5、For Elymus nutans, increasing irrigation frequency cannot significantly improve the forage yield, so taking on the rain-fed (no irrigation) can also achieve the same production efficiency in order to reduce costs.