Solving Over-Irrigation in Tunisia’s Citrus Sector 

This research, conducted as part of the Water Livelihood Initiative (WLI), would not have been possible without the financial support of USAID and CGIAR’s Research Program on Policies, Institutions, and Markets (PIM). The authors would also like to acknowledge our partners in this research,  namely the Faculty of Economics and Management, Tunis El Manar University, the Higher Agronomic Institute of Chott Mariem, University of Sousse, and the Faculty of Economic and Management Sciences of Nabeul, University of Carthage. 

-----------------

Across the drylands, managing water resources reasonably and sustainably is an absolute priority for agricultural sectors. In Tunisia, rainfed agriculture remains prevalent in the northern and central regions of Tunisia, but as climate change disrupts precipitation patterns, timing, and quantity, irrigated agriculture is expanding.  

With it comes the necessity to utilize available water resources sparingly in a country where the annual per capita renewable water allocation hovers around 400 cubic meters - a stark 100 m3 under the UN benchmark of absolute water scarcity.  

Tunisia-based ICARDA Agricultural Economists Boubaker Dhehibi and Aymen Frija collaborated with researchers from the universities of El Manar, Sousse, and Carthage to study the effectiveness of establishing a water pricing mechanism on citrus farmers to decrease over-irrigation.  

They surveyed a sample of 147 citrus farms in the Nabeul Governorate, a large peninsula in the northeast that concentrates most of the country’s citrus production. 

As rainfall falters and the irrigated perimeter expands, irrigation water use must be closely monitored to ensure that all farmers can access that resource, albeit sustainably. 

The researchers reached this benchmark by calculating the difference between the total water requirement for citrus and the efficient precipitation during one growing cycle – which spans from January to December. 

“Some farmers are equipped with a flow meter, which helped us assess their water consumption at the field level. For others, we relied on estimates provided by the water supply manager, based on irrigation duration and flow,” Dr. Dhehibi points out. 

The paper analyses farmers’ ability to pay a fine if they exceed the 5,000 m3/hectare threshold. “The fine itself would be costly enough for farmers to want to stay under the limit but low enough that they could pay it without hurting their income too badly,” explains the agricultural economist.

The study also recommends establishing a reward mechanism for those who safely remain under that limit.  

Water over-consumption in Tunisia concerns everyone: large landholders and smaller farms are guilty of it. To drive more sensible water use and protect farmers’ welfare, the authors recommend increasing farms’ technical efficiency and improving farmers’ knowledge of water.