Effects of Chemical Clogging on Drip-Tape Irrigation Uniformity

ABSTRACT The following four management schemes were evaluated for lessening the chemical clogging effects of high calcium content water in drip-tape: 1) above ground day-time water application, 2) above ground night-time water application, 3) subsurface placement of drip-tape, and 4) lowering the pH of the irrigation water. Calcium, magnesium and bicarbonate ions were injected into the water source to evaluate water qualities with electrical conductivities of 0.59, 1.12, and 2.02 dS/m. Irrigation duration for each management scheme was four hours daily over the 100-day investigation. Volumetric flow rate and emission uniformity were monitored. Partial and full clogging due to chemical precipitation occurred in all management schemes for the water with the highest salt content. By the end of the study, daily flow values in the laterals had decreased between 20 and 40% for this water. Corresponding flow reductions for the lowest salt content water varied between 3 and 15%. Of the management modes evaluated, reduction of water pH from 7.6 to 6.8, by sulfuric acid injection, provided the least clogging for all three water qualities.