The importance of the agri water footprint

-
The importance of the agri water footprint
The agriculture industry is considered as one of the biggest water users internationally. Photo: Annelie Coleman

Please explain what a water footprint is.

A water footprint is an indicator of the degree of sustainability with which freshwater is used for economic activities, such as food production. It provides information on two aspects of water use:

  • The total volume of fresh water used to produce the food product and deliver it to the end-consumer, measured along the entire supply chain of the product;
  • The degree of sustainability with which the fresh water was used. The volume of water used to produce the product – for example, the litres used to produce 1kg of beef – is referred to as the volumetric water footprint indicator.

Importantly, in order to judge this indicator as good or bad, it is important to assess the degree of its sustainability.

The water footprint is considered sustainable if the volume used is less than the available amount. Available water refers to the water available for use after leaving sufficient water in the river system to sustain the ecosystem.

If the water footprint is unsustainable, users are under obligation to adjust their behaviour accordingly.

A distinction is made between the different types of water used – rainwater (green water footprint), surface and groundwater (blue water footprint) and fresh water needed to dilute polluted water to ambient water quality standards (grey water footprint).

Thus, the water footprint also shows the source of water used to produce food products and considers the impact of pollution on the freshwater resource.

Such information is important to inform water users, managers and policymakers about the sustainable use of our scarce freshwater resource.

Knowing the availability and water usage situation in a region enables managers to inform users timeously to guard against using water in an unsustainable manner.

Has the footprint of livestock production in South Africa been established yet? How many litres of water are needed to produce a kilogram of beef?

Scientists from the Water Footprint Network in the Netherlands have included South Africa in a global study exploring the water footprints of various animal products.

They reported that the volumetric water footprint indicator of boneless beef in South Africa is 17 387l/ kg, compared with the global average of 15 414l/kg.

It should be noted, however, that a water footprint on a national scale does not provide reliable information to effectively inform sustainable water users. Given the diversity in climate and the environment within South Africa, it is reasonable to expect substantial variations in the volumetric water footprint indicator for different regions.

Moreover, variation in water availability in different regions suggests that the degree of sustainability will also differ. Thus, local research is necessary to assess the water footprints for various regions and production systems.

To date, no water footprint assessments have been conducted for the various livestock production regions in South Africa.

As part of a research project for the Water Research Commission (WRC), the University of the Free State’s Faculty of Natural and Agricultural Sciences is assessing the water footprint of, among others, beef production in a case study in the Free State and dairy production in the Free State and Southern Cape. The results will be published in due course.

Is the water footprint of crop production also receiving attention?

Yes, as the water footprint of the livestock industry is being researched, the Water Footprint Network has also reported the water footprint of various crops in South Africa as part of its global assessment.

In order to generate more reliable, context-specific information in South Africa, the faculty is in the process of assessing the water footprints of maize and wheat as part of our WRC research project.

Dr Michael van der Laan of the University of Pretoria is leading another project for the WRC where the water footprint of selected horticulture crops in South Africa is being assessed. So, while limited research has been done until recently in the country, the topic is now receiving a considerable amount of attention.

What attention does the agricultural water footprint assessment receive elsewhere in the world?
There is increasing awareness of water footprints globally. Given that the agriculture sector is considered to be a major user of fresh water, a good deal of emphasis is placed on the sector’s water footprint.

The focus is on informing consumers on the water footprint of the respective foods in their diet. Important for agriculturalists in a country such as South Africa is the fact that consumers are advised to change their diet in order to decrease their pressure on the scarce freshwater resource.

For example, they are advised to change to a more vegetarian diet as producing animal products requires more water than growing vegetables and other crops.

This recommendation, however, is based mainly on the volumetric water footprint indicator, while limited attention is given to the sustainability assessment.

It is important to provide consumers with this figure too, so that they can make properly informed decisions when considering changing their behaviour to decrease its environmental impact.

Do you think the South African agriculture industry is sufficiently aware of the impact of its water footprint on local water supply? If not, what should be done to rectify the situation, and by whom?

While the industry does have a good understanding that it is a major user of the freshwater resource, the awareness of the water footprint is still rather limited.

The benefit of the concept is to interpret water usage in the context of water availability to get insight into the sustainability with which water is used.

Researchers and the media have to put special emphasis on raising awareness of the water footprint of a product as an indicator of sustainable use for food production.

However, as mentioned already, care should be taken not to misuse the information by placing too much emphasis on the volumetric footprint indicator at the expense of the sustainability of the water footprint.

Can or should water footprints be regulated and controlled through legislation? If so, how?
Water footprints do not necessarily have to be regulated through legislation. Consumers could be educated on the water footprint as a sustainability indicator.

They could then become agents of change by buying products that report a sustainable water footprint on their labels. Water users along the agri-food value chain should then be incentivised to report the footprint, and adjust their behaviour where needed to ensure that they use water sustainably.

There may even be a niche market for those leading the way in reporting the sustainability of the product’s water footprint. More research, however, is needed to determine the most effective way through which information can be communicated to the consumer.

How can the industry improve its water footprint?
It stands to reason that crops require a certain amount of water to grow. By maximising the use of rainwater, users can minimise the volume of surface and groundwater needed.

They should also take care to minimise pollution of the freshwater resource in the production of crops. By doing this, the grey water footprint can be reduced, decreasing the total water footprint of the product.

In more extreme situations, where a region is known to have little water available, farmers should consider changing to agricultural products that require less water.

What would the long-term impact be should the industry continue as it is?
At this stage, there is no evidence to judge the water footprint of the agriculture industry as unsustainable, so it’s unclear what the impact would be if we continue as is.

Given the scarcity of fresh water in the country, however, it’s crucial that we consider the degree of sustainability with which we use it. Assessing the water footprint of agri-food production is thus extremely important at this stage.

Water users and managers need reliable information on the degree of sustainability with which we use fresh water.

If the information is not available and too much water is used, the first impact will be on the ecosystem in the river system. Simply put, there will not be enough water to sustain it.

Ultimately, however, we need sufficient water to feed the growing population. We have to generate reliable information to inform users timeously to adjust their practices where necessary to ensure that we have sufficient water to produce food in future.

Southern Africa is suffering from one of the worst droughts in decades. Could an improved water footprint have mitigated its effect, and how?
The main benefit of knowing the water footprint is to have a good understanding of water use in relation to availability in a particular region.

If water use and availability are close to each other in a period with normal rainfall, there is a high risk that the usage will exceed availability in periods of drought. Agricultural practices associated with lower water requirement may thus may provide an additional buffer to water users to overcome the negative effect of a decrease in availability due to drought.

Adopting practices that minimise the amount of water required will reduce the effects of drought on the business.

It has to be recognised, however, that dryland agriculture is completely dependent on rainfall. Even after selecting, for example, crops or cultivars that require the least amount of water and strictly following practices to conserve moisture in the soil, a farmer will still need rainfall to meet the total water requirement of the crop.

Thus, while a smaller water footprint could mitigate the effect of drought, it would never eliminate the effect of severe droughts completely.

Phone Dr Henry Jordaan on 051 401 9648 or email [email protected].