Impact of deficit irrigation strategies on water use and productivity of vegetable crops in a semi-arid context of Tunisia

• Published in: Desalination and water treatment 2022-07, Vol.263, p.109-115
• Main Authors: Yacoubi, Samir, Slatni, Adel, Azzi, Raouia, Oueslati, Taoufik
• Format: Article
• Language: English
• Subjects: Deficit irrigation; Irrigation simulations; Relative yield loss; Water productivity
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2022.28212

Irrigated agriculture in arid and semi-arid environments is characterized by acute imbalance between rainfall and evapotranspiration and tough competition for water. It is against this backdrop that water use efficiency is becoming a must. This study is targeted to evaluate the effect of deficit irrigation on water requirements, yield and water productivity of potato and tomato crops under average and very high climatic conditions of 2016 and 2017 respectively. The case study is the Cherfech irrigation district located in the northern of Tunisia. For this purposes, the FAO/ CROPWAT irrigation scheduling and simulation model was used to identify appropriate deficit irrigation strategies for improving water conservation with acceptable impacts on yields. Deficit irrigation strategies were evaluated through parameters of irrigation, relative crop evapotranspiration, relative yield loss as well as water productivity and economic water productivity. Results indicate that deficit irrigation is practicable under average water demand for both potato and tomato crops. For tomato, adoption of deficit irrigation is less feasible particularly under very high demand. For a relative yield losses threshold of 25%, results show that for potato, optimal season irrigation could be reduced by 43.3% and 31.6%, respectively for average and very high climatic conditions. For tomato crop, optimal irrigation requirements could be reduced by 33.3% for average demand and 31% for very high water demand. Regarding the water use indexes, results show that water conservation due to deficit irrigation strategies improves water productivity under the average water demand more than the very high demand. This improvement was more noticeable for potato than tomato. Furthermore, economic water productivity is more affected by the difference in potato and tomato prices for average (2016) and very high (2017) water demand conditions.