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An integrated agro-economic model for land and water use optimization

11 Jul 2019

A specific MADFORWATER task was dedicated to the development and implementation of an integrated agro-economic model that can be used to optimize land and water use in agriculture.

Built and calibrated in the three case studies area of MADFORWATER – the irrigated farming system in the Kafr-El- Sheikh Region in Egypt, the citrus farming system in the Souss-Massa region in Morocco and the Nabeul Governorate in Tunisia – the developed decision support tool has been structured to simulate treatment and irrigation technological solutions as well as related economic and regulatory instruments identified and tested in MADFORWATER. Given the representativeness of the case studies and the generality of the model, the developed tool can be up-scaled and replicated in order to support the definition of strategies and the identification of economic instruments for basin-scale water resource management in agriculture.

Indeed, it can include different types of crops, intensification levels, use of fertilizers, chemicals, labor use, tillage operations, water delivery periods, as well as different types of water sources. Further, the possibility to input the data and to export the results through a data sheet will make easier the use of the model in other case studies and by non-expert decision makers.

The developed model allows to identify the optimal allocation of water of different qualities that can be made available to agriculture by treating a larger amount of wastewater. Ultimately, the model is capable to assess the convenience to adopt in each specific context the wastewater treatment and irrigation technologies developed by MADFORWATER.

The reuse of treated wastewater is expected to reduce the amount of freshwater consumed as well as fertilizer crop requirements, with a positive impact on the cost of cultivation. On the other side, the modernization of irrigation systems that in some cases can be associated with the reuse of treated wastewater can affect the irrigation system performance in terms of efficiency, uniformity and/or adequacy. The impact of the adoption of innovative treatment and irrigation technologies as well as of water policies and economic instruments is analysed, by assessing their impact on the most relevant parameters:

  • Land use, cropping pattern, crop production
  • Water use: consumption from different sources, water productivity, water marginal value, water price
  • Fertilizer use
  • Drained water
  • System performance index, defined as the ratio between water supplied and water demand
  • Socio-economic variables: farm income, labor use, public subsidies for innovation.

In the first step of model application, for each case studies area of MADFORWATER, the set of model parameters associated to an optimized cropping pattern as close as possible to the current one has been identified. As an example, some representative model parameters relative to the current situation are reported below for the three study areas.

Tunisian case study (Nabeul Governorate): water use  in the current scenario in three representative farms

Egyptian case study (irrigated farming system in the Kafr-El- Sheikh Region): drained and used water in the current scenario

Moroccan case study (citrus farming system in the Souss-Massa region): fertilizer use in the current scenario

In the second step of model application, that will be implemented during the last year of MADFORWATER, the current values of the relevant parameters will be compared to the corresponding values relative to several future scenarios, characterized by the inclusion in the model of several factors, such as a higher availability of treated wastewater, more efficient irrigation technologies, different cropping patterns or economic instruments. Thus, the upgraded version of the model will allow to evaluate the impact of the different policies and strategies aimed at enhancing the reuse of treated wastewater in agriculture in the framework of broader water and land management strategies that countries could implement to ensure the long-term sustainability of the water resource.