Fertigation guidelines for furrow irrigation

Abstract

A mathematical model was developed to simulate the application efficiency and uniformity of water-soluble fertilizers through furrow irrigation. The model simulates solute mass balance and transport for one-dimensional unsteady flow during the advance and post-advance phases of a furrow irrigation event. The model was programmed to determine the best timing and duration of fertilizer injection using two performance indices: solute application efficiency and solute application uniformity. The results from the model were compared with two sets of field data and were found to be in close agreement in terms of advance trajectories and surface water solute concentrations. Nearly 50,000 simulations were performed with the model and the results were analyzed in terms of best injection start and end times for fertilizer application efficiency and uniformity. It was found that the best injection duration time was from 5 to 15% of the time of cutoff for a complete irrigation. Most of the cases showed that the injection should take place in a relatively short time span, and at a relatively high injection rate.