Effect of dynamic pressure and emitter type on irrigation and fertigation uniformity of drip irrigation systems

Abstract

Enhancing the anti-clogging efficacy of emitters within drip irrigation systems through dynamic pressure (DP) is gaining attention. However, DP may affect the irrigation uniformity and fertigation uniformity. The laboratory experiment on irrigation and fertigation uniformity was conducted using the Non-axisymmetric Venturi Injector and urea. The amplitude, cycle time, and waveform of DP were utilized to establish pressure schemes and compared with the constant pressure (CP) of 100 kPa, to evaluate the irrigation and fertigation uniformity of three types of drip tapes. Results indicate that the type of drip tapes has a very significant effect on irrigation uniformity (p < 0.01) and significantly affects the fertilizer application rate uniformity (p < 0.05). The amplitude, cycle time, and waveform of DP don't significantly affect the irrigation uniformity. The irrigation emission uniformity under DP relative to CP exhibited variations from −3.118 % to 1.055 %. Only 4/27 of DP schemes failed to achieve a WEU that classified as 'Excellent', but were still classified as 'Good' when CP was rated as 'Excellent'. DP has a slight effect on the flow rate. The cycle time, and waveform of DP significantly affect the uniformity of fertilization concentration and application rate (p < 0.05). DP enhanced the concentration emission uniformity by 49.885 % and the fertilizer application rate emission uniformity of by 51.629 %, albeit requiring 4.612 % more fertigation time. DP can enable drip systems to maintain good irrigation uniformity while achieving superior fertigation uniformity. To achieve a more uniform irrigation and fertilization, utilizing appropriate parameter combinations of DP tailored to different drip tape types is recommended.