Regulation of field environmental condition by sprinkler irrigation and its effect on water use efficiency of winter wheat

A field experiment was carried out to study the effects of sprinkler irrigation on air temperature and humidity near ground surface, field evaporation potential (water surface evaporation measured using 20 cm standard pan on the top of canopy) and water use efficiency of winter wheat under different climate conditions. A cooling treatment by spraying a little amount of water using sprinkler irrigation system was also conducted. Its effect on canopy temperature against the dry hot wind was studied. Experimental results show that sprinkler irrigation significantly decreased the maximum and average daily air temperature and increased the minimum and average daily relative humidity when it was dry. Field evaporation potential in sprinkler irrigation field was greatly lower than that in surface irrigation field. Cooling treatment showed that spraying little amount of water can greatly decrease canopy temperature. Decrease of field evaporation potential is positively related to spraying water quantity and the maximum daily temperature, and negatively related to the minimum relative humidity and wind speed. Winter wheat yield and water use efficiency under sprinkler irrigation condition were higher than that under surface irrigation condition.