Evaluation Methods of Sprinkler Water Nonuniformity

Overlapped sprinkler water distributions were tested to determine the relationship between Distribution Uniformity (DU) and Christiansen Uniformity Coefficient ( CU ). The results demonstrated that DU increases linearly with an increase of CU. The value of DU approximates 66% when CU equals the required value of 75% by the standard. Field experiments were conducted to observe the spatial distributions of soil water content under sprinkler irrigation. We found that the water was more uniformly distributed in the soil than that measured on the ground surface. The influences of corn canopy on sprinkler water application pattern were also studied by field experiments. Sprinkler water pattern may be modified by crop canopy and the water uniformity below canopy is usually greater than that above canopy.