| Sprinkler possess good points on saving water and raising yield. Now there is up to 2 million hectare in china. But when designing a sprinkler system, the basic parameter to be used, for example evapotranspiration, is got by experiment under surface irrigation condition. For not accounting for sprinkler points, the parameters of irrigation quota on each application irrigation duty and irrigation time used in practice under sprinkler condition are different to some extent with those under surface irrigation. Accounting for these points, the major objectives in this paper are to research sprinkler droplet evaporation, to study microclimate changes under sprinkler condition, to develop the model of soil water movement , to study the growing characteristics of winter wheat and summer corn as ~vel1 as to determine the sprinkler irrigation duty arid irrigation quota on each application. And then this paper can provide date which is used to achieve high yield.Sprinkler water breaks into different-sized droplets and different size causes different evaporation. By statistic analysis, sprinkler droplets show up-limitedlog-normal distribution (ULLN). Droplets evaporate during the flying process in the air, and the flying trace can be modeled by the trajectory differential equation. Single droplet evaporation can be got by comparing the difference of drop size between at the nozzle outlet and at the site near field. Combining the trajectory differential equation and the model of droplet distribution, the changing process of droplet is modeled. And then the evaporation is computed by using mean statistic diameter. The modeled data show that the date predicted conforms to the date measured, and about sixty percent of the difference between the predicted and the measured lessens than one percent. By using this model the sprinkler evaporation of nozzles with diameter 6.0/3.1mm and 8.0/3.1mm operating at different conditions ranges from 2.06% to 7.57%.Sprinlder evaporation causes microclimate changes of the field. Air temperature dropping and humidity rising can be measured in the sprinkling zone. When operating under a single-line condition, the changes of air temperature and humidity of different point in the sprinkling area are not same . Especially working under wind condition, the variance is more distinctive. The difference of air temperature and the difference of humidity downwind is greater than that deadwind. When Operating under multi-line condition, spraying zone of sprinklers overlap, which can lessen the impact of wind on thechangCs of temperatUre and humidity. SprinkIer still influence the microclimate after irrigation,and the lower temperatUre and higher humidity will last for a few days. Soil watercontent will be high aller sprinkler which affects the changes of soiltemperatUre. When sprinkling in winter, the added ex-temperatUre in the upper layer ishigh but will lessen when going deeper layeL At the point of the tendency of multi-daythe range of added ex-temperatUre will decrease whi1e time going on.During sprinkling, field gets water discontinuously, which means the pIot gets wateronly when sprinkler water wall reach the fieId, and during the other time during a rotatingcircle, the soil water in the same plot evaporates and diffuses. Soil water movement ismodeled at tWo facts: instantaneous sprinkler rate and common mean sprinkler rate.According to the curve of soil water distribution on the profile and the calculation of waterequilibrium, the data predicted by instantaneous sprinkler rate are more conform to themeasured than that by common mean sprinkIer rate.The affect of sprinkler on microclimate impacts the crop's growingprinciples. As for winter wheat, the available tiIlering is high, more root lies inupper lnyer and crop water productivity is high, etc. Experiments show that the properirrigation quota on each aPplication for winter wheat is 45mm or 52.5mm, irrigation duty is0.83ET.; for summer com, proper irrigation quota on each application a...
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