Evaluating the water application uniformity of center pivot irrigation systems in northern China

The use of center pivot irrigation systems to irrigate large fields has gradually been increased in China. Water application uniformity is usually regarded as the most important parameter to quantify irrigation quality. Field tests of six center pivot irrigation systems in northern China were conducted to evaluate the water application uniformity. Coefficient of uniformity ranged from 60.0% to 89.0%. The system with high inlet pressure and large discharge of end gun resulted in low water application uniformity and high application depth at the area irrigated by end gun. And the system with low inlet pressure had a downward tendency of the water application depth along the lateral. Small height between sprinkler and crop canopy also resulted in poor application uniformity. The system equipped with the rotating spray plate sprinklers had higher water application uniformity than the systems with the fixed spray plate sprinklers. The long length system had higher water application uniformity than the short length system with the same sprinklers. High water application uniformity occurred in the middle spans. These findings are expected to draw the attention of farm managers to the factors influencing the water application uniformity during system operation. © 2019, Asian Association for Agricultural Engineering. All rights reserved.