Literature review on Water Productivity of date palm trees in Tunisian agro systems

The sustainability of agricultural productivity is closely related to the optimal exploitation of natural resources, namely the efficient water resources management. The evaluation of the effectiveness of the adopted strategies and the applied practices and systems relies on a number of criteria and parameters of which water productivity indices represent the most relevant criteria. In this context, the present study aims to assess the water productivity for date palm cultivation in Tunisia based on an accurate literature review of the previously published scientific papers and reports related to the different studies carried out in these agro-oases regions of the country for the evaluation of the different indices of water productivity. This review represents the main baseline document highlighting in an exhaustive way the challenging features related to water productivity for date palm agro-systems. The outcome of this review indicates that (i) the cultivated date surface is expanding, covering more than 58.000 ha with a total production of 355.000 tons in 2021(ii) the distribution of irrigation water is variable and irregular. iii) The reported water supply for date palm range from 20,000 to 30,000 m3/ha while a number of scientific-based calculations estimate the crop water requirements for regular date palm production is between 10,000 and 18,000 m3/ha (iv) the efficiency of water conservation techniques is related to numerous in farm factors related to the old traditional surface irrigation systems, to the soil salinization, alkalization and permeability loss and to the overexploitation issues of water resources that reaching is growing and may impact the productivity of date palms and sustainability of the production system (v) the estimation of the biophysical water productivity based on the reported data reaching barely 0.66kg/m3. This overview highlights the need for an accurate evaluation of the ecological efficiency of the used management measures to a clear appreciation of the new strategies and policies to face the current constraints with regard to all different driving forces influencing water productivity both at the macro and micro scale.