Irrigation Management Evaluation And Hydrosalinity Balance Within Kalaat El Andalous Irrigation District, North‐East Tunisia

Abstract

AbstractDuring 2005–2010 the annual water balance was calculated within Kalaat El Andalous irrigation district and recorded values ranged from −0.77 million m3 (−257 m3 ha−1) to +3.64 million m3 (+1210 m3 ha−1). Monthly analysis of the water balance revealed two distinct phases. Through the first phase (September–May), the water balance showed a highly variable tendency due to erratic rainfall and irrigation water inflows. However, during the second phase (June–August) the water balance remained positive, reflecting farmers’ tendency to over‐irrigate. Analysis of water productivity confirmed this result mainly during the full irrigation period (June–August). Therefore, the average annual drainage fraction was 26%. The assessment of salt balances during 2005–2010 indicated a general tendency for soil desalination (average annual salt balance: −25 600 t (−8.5 t ha−1)). Monthly analysis revealed the succession of three distinct phases. The first phase occurring during September–November is characterized mainly by salts leaching and secondly by salts accumulating. The second phase spanning December–April is characterized by salts leaching, while the third phase spanning May–August is characterized by salts accumulating. Thus, 95% of accumulated salts were recorded during May–August and 5% during September–November, while 91% of leached salts were recorded through December–April and 9% during September–November. © 2018 John Wiley & Sons, Ltd.