Saving Water in Irrigation

A. Vargas, R.J. Hogeboom & J.F. Schyns

 

Background

 

Freshwater scarcity is a major global concern and irrigation is a key piece of the puzzle. Irrigation is crucial in dry climates where precipitation is regularly insufficient for plant growth, and it is typically required to maintain crop productivity during dry periods elsewhere.  Irrigated agriculture plays a fundamental role in the provision of food worldwide, generation of renewable energy, and economic development.  Simultaneously, irrigation is also one of the key drivers behind the depletion of freshwater resources, contributing to water scarcity.

In the European context, water scarcity affects 11% of the population and 17% of the territory (European Commission, 2007). The proportion of water withdrawals due to agriculture within the EU territory is around 45%, most thereof used for irrigation, where the southern European countries claim approximately two-thirds of the total (Eurostat, 2019). Figure 1 displays the concentrations of irrigated areas, expressed as percentage of irrigated area in relation to the total utilised agricultural area, where the highest, noticeably, are located in Southern Europe.

In the EU, irrigation practice is mainly governed by the Water Framework Directive (WFD) and the Common Agricultural Policy (CAP). Where the WFD provides a basis to ensure the long-term sustainable use of water bodies across Europe, the CAP decidedly shapes the course of agricultural practices in Europe. The CAP seeks to integrate objectives of the WFD, and both policy documents have a clear bearing on water use in agriculture. However, a comprehensive integration of the two policies has not been fully achieved and the water challenges prove persistent. The major question that still stands, therefore, is how the EU can effectively save water in irrigated agriculture?

In this study, we set out to assess the consistency of a number of innovations that influence water savings in irrigation with various narratives in which they are embedded, within the context of the EU agricultural sector.  

 

Figure 1. Share of irrigated areas in utilised agricultural areas (UAA). Source: Eurostat (online data code: ef_poirrig).

 

Dimensions of water savings

 

To better understand water savings and how to achieve them, we highlight three different dimensions of water savings, following Hoekstra (2020) (see NEXUS TIMES publication in related work below), namely, production, trade and consumption. The nexus originated by irrigated agriculture in Europe requires solutions from all dimensions as it is expected that irrigation will continue to fulfil all of its functions while still sustainably managing Europe’s freshwater resources.

The production dimension focuses on the supply side. For crop production, it considers the intensity of application of inputs. Water-wise, it encompasses how water is applied to crops and its consequent impact on production.

The trade dimension focuses on the international trade in crop products, where water is traded in virtual form. Trade is an opportunity to release the pressures imposed on the water bodies, when production patterns are adapted by looking at where we can best produce certain crops from a water point of view.

A consumption dimension looks at the demand side, focusing on consumption patterns. It leaves the food supply behind and targets the consumers with the aim to reduce water consumption. There are two main strategies employed to reduce the water footprint considering a consumption dimension: dietary changes and reduction of food waste.

 

Innovations to achieve water savings

 

There are many innovations that have been developed with the potential to achieve water savings in agriculture. In the first place, agricultural management practices can significantly influence both crop water use and water productivity. In the second place, smart irrigation strategies can promote reductions in the application of water in the field - without significantly lowering yields. Moreover, there are efficient irrigation techniques and technologies that facilitate crop water uptake and reduce water use. Lastly, particular socio-economic responses can support water savings in irrigation as well, by steering changes in behaviour among producers and consumers.

It is worthy to keep in mind that while these innovations can achieve water savings, the potential to do so varies greatly, both in particular and combined. For example, on average, drip sub-surface irrigation and deficit irrigation are associated with the most considerable reductions on the BWF (Chukalla, 2015). However, a combination of the innovations thereof along with the practice of mulching is associated with even larger reductions, especially if the mulches are of synthetic origin. Figure 2 displays the potential reduction of the water footprint of a crop for different combinations of innovations.

 

Figure 2. Change in water footprints in different management practices. SSD stands for sub-surface drip, FI for full irrigation, DI for deficit irrigation, NoML for mulching practice, OML for organic mulching and SML for synthetic mulching. Source: Chukalla et al. 2015 (see related work below).

 

Effective adoption of particular water-saving innovations, nevertheless, depends on more than their water-savings potential alone. Uptake and acceptance varies as a function of the narrative or perspective one holds on the way crops should be produced and which role irrigation ought to play therein. Given the inherent complexity of interlinked water systems and the wide spectrum of narratives that exist, a careful understanding of both is crucial or order to make informed policy choices.

 

The five narratives of European crop production

 

Our analysis identified five overarching narratives that govern crop production in the EU. Each narrative assigns a specific role to water and irrigation, and hence promotes uptake of different water-saving innovations. The five narratives and their preferred broad innovation categories to save water in EU agriculture are:

  1. Food Security – Irrigation is a means to meet EU food demand. Innovations that increase yield and water productivity of food crops are the focus.
  2. Market Competitiveness – Irrigation is a means to increase the global competitiveness of the European agricultural market and improve the EU economy. Innovations that enhance market opportunities and maximize profit are the focus.
  3. Environmental Protection – Irrigation is a primary cause of the degradation of natural resources. Innovations to reduce the use of water are preferred.
  4. Circular Economy – Irrigation is a means to support a low carbon economy based on the production of biofuels. Innovations that support reduced greenhouse gas emissions and increase yield and water productivity of energy crops are the focus.
  5. Technological Optimism – Irrigation is a technological challenge that may boost crop production. Innovations based on the use of technology that maximizes irrigation efficiency and crop water productivity are the focus.

 

Results and conclusions

 

Since each narrative assigns a specific role to water and irrigation, it promotes uptake of different (sets of) water-saving innovations. We assessed the consistency within the different narratives of the selected innovations and their feasibility (external constraints – natural limits), viability (internal constraints – processes under human control) and desirability (implications for stakeholders). Table 1 presents part of the results from the assessment for feasibility and viability. Hereto, we inventoried a large number of innovations and described their potential to achieve water savings in irrigation using Quantitative Story-Telling as a method. We used various case studies and scenarios from literature and the results of a second stakeholder engagement to support the assessment.

 

Table 1. Main results obtained from the feasibility and viability check on the five narratives.

 

The results confirmed that the main goals and assumptions behind each narrative exert a significant influence on the uptake of a given water-saving innovation. Moreover, it was found that there are trade-offs in selection of particular innovations between the different narratives and that socio-economic innovations form an important part of any innovation mix.

The path towards effectively saving water in EU agriculture requires both clarity on the goals sought (here framed through the lens of dominant narratives) and coherence between these goals and the innovations that support them. The broad spectrum of goals currently portrayed by the CAP and the incomplete integration with WFD objectives illustrate such clarity and coherence is still lacking in EU policy. The increased understanding through this work on viable narratives and their preferred innovations contributes towards drafting more effective EU policies that help solve the persistent environmental challenges related to water.

 

Related Work

 

Teams Involved