Using the step by step models to evaluate field application uniformity of subsurface drip irrigation systems

Abstract

Compared to other irrigation methods, drip irrigation systems (DI) are considered one of the most efficient form of irrigation. Subsurface drip irrigation allowed reducing water losses by evaporation, runoff, and deep percolation comparing to other irrigation systems supplying water on soil surface. Field evaluation of Uniformity of water applications and its stability, however, are still a matter of controversy and deserve more investigation, since the collection of water discharged needs to excavate the soil around the emitters. Experiments carried out at the Department of Rural and Agrifood Engineering of Polytechnic University of Valencia allowed describing a methodology to assess the performance of drip irrigation through hydraulic characterizations and an emission uniformity coefficient, using the step by step models. Calculations evidenced that operating pressures on emitters ranged between 127.6 kPa and 131.7 kPa, whereas the corresponding flow rates varied from 4.00 L/h and 4.07 L/h, with an average value of 4.02 L/h. Variability in the emitters’ flow rate resulted very limited due to the short length of the lateral (25.6 m). However, more attention should be paid to this for a longer field dimensions. Consequently, the value of emission uniformity coefficient was equal to 96.3%, testifying the uniform water distribution within the sub-plot.