Design Nomographs for Trickle Irrigation Systems

Nomographs relating discharge rate, plant uptake and soil water potential at a reference point are developed for trickle irrigation systems. The hydraulic conductivity K is assumed to be related to pressure head h by $K_0$ exp (αh) in which $K_0$ and α are empirical constants representative of the specific soil. Point or disc sources located at the soil surface as well as arrays of line sources located at the soil surface or buried at depth d are considered. For point or disc sources, the plant water uptake is from a cylindrical volume or a buried horizontal disc. For line source arrays, however, a one‐dimensional uptake is assumed. The reference point for line sources is chosen at depth $Z_M$ midway between the line emitters. For disc or cylindrical uptake, the reference point is located at the outer edge of the maximum depth of withdrawal. The nomographs are easy to use and provide answers without performing tedious computations.