dimanche 4 janvier 2015

33- Water and irrigation -2- Agriculture and water consumption


I read with great interest and shared on my social networks, because I agree with most, an article in the November 24 appeared in the French newspaper La Croix, on the division of water.

At the beginning of the article, a first question is asked, important and I join verbatim, on the main uses of water in France.

"What are the uses of water?

Three groups of actors draw water into the natural environment, communities to supply drinking water to homes, the nuclear industry to cool power plants, and farmers in irrigated areas. The first two uses are almost neutral in the natural environment. Indeed, the water used by homes or by power plants is discharged into rivers after use and depollution. It is quite different for agricultural use: irrigation water is completely "consumed" by the plant. In net consumption, farmers draw 50% of the volumes, a proportion that reaches 70% during the summer months.”

I want to make a comment about it. The article clearly states that domestic and industrial uses are neutral to the natural environment, but not agricultural use.
I do not agree with this view.

Water consumption does not exist. The water does not disappear. The amount of water available on Earth is virtually the same today than it was a thousand years ago.
The water is not consumed, it is used for drinking, washing, for irrigation, for the needs of industry, for the energy production, to make gas (oxygen and hydrogen), for dissolve all sorts of things.

Agriculture uses water for basic needs of plants and animals, but does not consume it.
Plants use water for their physiological needs, then reject it, either as evaporation or within the food product.
Water in excess reaches the water tables feeding them, or water courses participating maintain a sufficient level, even in summer.
The evaporated water joins the atmosphere as water vapor, feeding the air humidity and clouds, thus precipitation.
Water "exported" in food, ends up being consumed to be, as it says in the article, "discharged into rivers after use and depollution."
In short, this water is not consumed, it changes state. It is very different.
Water resources may change locally, but not globally.

Yet there is a form of water consumption. But here we only talk about fresh water and drinking water. Because the problem is there. Here we talk about something else. Terrestrial living organisms need, in their vast majority, freshwater and drinking.

But let's be clear, without fresh water, there cannot be any food production. In other words, we cannot produce food without water. Agriculture is, and will always be a freshwater demanding activity.

However, it would be wrong to deny the problem of water waste in agriculture. This is due to poor management of water available at a given time and a given place.
Indeed, agriculture needs fresh water, not necessarily drinking, but soft. Drinking water is especially necessary in the washing of the harvested product, before its marketing process, in order not to risk contaminating it, with unfit for human consumption water. In areas where fresh water is scarce, there may be competition in the use of the available water between the vital human needs (drinking), household (washing, bathing, watering gardens), industrial, energy and agriculture needs.
Here we enter a much more delicate zone, politics. Because the division of water is primarily a political problem. What are the activities that a given territorial community wants to focus on? At what point in local politics the debate intervenes? Are there secret interests?
Water is a political weapon, and even geopolitical. Some countries know this very well, when they built large dams on rivers that provide water to other neighboring countries, located downstream. Today, in developed countries, water is an important object of attention, and it is a powerful means of political pressure.
Whatever the political pressure, a local community must know how to balance the economic activities it accommodates.

Why must agriculture save water? Primarily to balance water availability across all uses. Agriculture is the largest consumer of fresh water in the world, and it's because it must make a special effort in this direction.

And here, there are several considerations that come into play.
- To save water in agriculture, it is necessary to have efficient irrigation systems. All these systems require energy, and a heavy investment in irrigation infrastructure. Everyone cannot afford to make this investment.
- Infrastructure investments must be accompanied by energy investments. The water pumps for irrigation do not run alone. Therefore, an electrical availability is needed, with necessary production and distribution networks, or heat engines, greedy and pollutants.
- Lots of areas or regions, have a water policy which does not encourage the farmer to make this investment. Only the water pricing by used volume will be motivating, because farmers will be encouraged to make the necessary investments in order to lower the water bill. Billing per hectare is still very (too much) prevalent, that is a fixed payment regardless of actual consumption.
- Traditional flood irrigation has the disadvantage of its high water consumption, but it keeps some ecosystems assets, around the water courses fed by water in excess. The reduction in water consumption can have very serious consequences for the survival of local plant and animal species.
- Reducing the amount of water used in agriculture also requires the creation of training networks, advice and monitoring, because it requires a significant technical change in the farms.

    Outflow of a coton plot, with flood irrigation

In short, the irrigation management in order to save fresh water is not neutral, nor on the cost of food, nor on the environmental impact of caused changes.
Agriculture has not only an indisputable role in food production, it also has a major role in maintaining ecosystems.

All reforms on agricultural production methods, systematically affect, not always in a well measured level, the surrounding ecosystems.

Many people tend to look at agriculture, primarily as a major source of pollution. It has been true, it is much less today. Not all is perfect, far from it. But beware of hasty political decisions without in-depth studies of the potential impacts at all levels, particularly in relation to water.

Never forget that without water, there cannot be agricultural production, so no food production.
Eat and drink will always remain the first basic needs of all living beings.

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