EFFECTIVENESS OF BORDER IRRIGATION - A CASE-STUDY

A method for the evaluation of adequacy, distribution and application efficiencies of border irrigation is proposed. A mathematical model fo r the simulation of surface runoff and infiltration is applied in orde r to analyse the waterings carried out according to traditional practi ce in the lower Po valley and according to systematic, full and defici t irrigation, on plots cropped with clover ley and spring maize. In th e application of the model, it is assumed that the water stored in the root zone may be identified with the readily available water. The com putations make it possible to analyse the traditional parameters and t o find their optimal values for a selected adequacy, i.e. for a select ed percentage of the length-of-run adequately irrigated. The model sho ws that the traditional practice causes an over-irrigation and that si gnificant water savings of nearly 11% may be made in comparison with t he experimental values. (C) 1997 Silsoe Research Institute.