DETERMINATION OF DESIGN INFLOW RATE IN FURROW IRRIGATION USING SIMULATED ADVANCE AND RECESSION CURVES

Abstract

Advance and recession curves were simulated for three stages of maize growth in furrow irrigation. The selected stages were: the emergence stage, two weeks after planting; the development stage, about two months after planting; and the maturing stage, about one month to harvest time. The advance and recession times were predicted for successive points along the furrow lines for various inflow rates at the development stage of the crop growth using three models. The simulated advance and recession data were used to compute the intake opportunity time distribution along the furrow line. The infiltrated depth distribution and hence the water application efficiency and distribution uniformity were computed for the inflow rate, which gave 87% and 89% for the maize emergence stage: 75% and 60% for the maize development stage and 95% and 89% for the maize maturing stage. The design inflow rate for each furrow was taken as the minimum inflow rate which gave rise to a minimum water application efficiency of 60% and a minimum distribution uniformity of 75%. It is recommended that the procedure described in this work is useful for the modification of existing furrow irrigation systems and the establishment of new ones. Also, the design procedure presented can be used for any field that is suitable for furrow irrigation system by making use of the relevant parameter estimates that can be obtained from the field.