Evaluation of Drip Fertigation Uniformity Affected by Injector Type, Pressure Difference and Lateral Layout

The effects of three injector types (differential pressure tank, Venturi injector and water‐driven piston proportional pump), three pressure differences (0.10, 0.15 and 0.20 MPa) and two lateral layouts (longitudinal and transversal) on drip fertigation uniformity were comprehensively evaluated through field experiments. No statistically significant differences in water uniformity were found between injector types or pressure differences, while the influence of lateral layouts on water uniformity was significant ( α = 0.05). All affecting factors showed an extremely significant influence on fertilizer uniformity ( α = 0.01). Water uniformity was better than fertilizer uniformity, both of which generally decreased with increasing pressure differences. The differential pressure tank produced a lower water and fertilizer uniformity than the Venturi injector and proportional pump. The longitudinal lateral layout produced lower fertigation uniformity than the transversal lateral layout. To ensure both high water and fertilizer uniformity in fertigation systems, a Venturi injector and a proportional pump with relatively constant fertilizer concentration are recommended. When a differential pressure tank is used, the differential pressure should be minimized to mitigate the decrease in fertilizer concentration. The differential pressure tank can give high fertigation uniformity (≥ 90%) comparable to the Venturi injector and proportional pump if the transversal lateral layout is further applied. The research provides scientific guidance for the design and operational management of drip fertigation systems in greenhouse vegetables or field crops.