Irrigating and fertilizing crops from a single installation, this is how a fertigation system works. A more sustainable system that reduces costs and environmental impact and improves resource efficiency. The agricultural sector joins innovation to transform itself. One more impulse to take care of the planet.
Types of irrigation: towards a more sustainable and efficient system
Traditional irrigation systems such as furrow or flood irrigation have been giving way to sprinkler irrigation -which drops water on crops in a sort of rain-, and drip irrigation -the most efficient technology, since it involves applying the right dose directly to plant roots-. Find out more about irrigation types.
One in four people could face extreme water shortages worldwide by 2025, according to projections in the article Implementing sustainable irrigation in water-scarce regions under the impact of climate change, published in 2020 in the journal Agronomy. In it, Greek and Cypriot researchers review existing irrigation systems in both outdoor and protected crops and argue that the conversion of traditional methods (such as open ditches or giving "drink" to the fields from tractors) in pressurized pipes, and especially in drip irrigation would mean water savings of up to 90%.
"There are many types of irrigation, but the most sustainable, and the one that represents a major future trend is drip irrigation," says César Marcos, specialized journalist and coordinator of the Alliance for Sustainable Agriculture, ALAS. It is also known as precision irrigation (in fact, it is linked to the so-called precision agriculture), supplies water, in measured doses, directly to the roots of each plant, and is a technology encouraged both by the SDGs (Sustainable Development Goals) of the 2030 Agenda and by the FAO (Food and Agriculture Organization of the United Nations).
Israel was a pioneer
Starting in the 1950s, Israel began to innovate with drip irrigation (although some authors claim that it had already been tested in Australia in the 1940s). "It is the most advanced agricultural irrigation system in the world," describes the Israeli Institute for Export and International Cooperation. The Middle Eastern country, with desert in a large part of its territory and irrigation on half of its arable land, is also a pioneer in controlling this type of technology by computer, which "also makes it possible to supply fertilizers with water", says Marcos, referring to what is known as "fertilizer irrigation".
"It is more expensive and complicated to install, but much more sustainable, so it is being imposed, both above ground, at the foot of the plant, and buried, which further prevents evaporation," says Francisco Javier Sanchez de Molina Peñuela, head of Gardening and Green Spaces of the natural engineering consulting firm Sylvestris.
"It is said that subway drip irrigation does not work because the roots end up blocking it; it is not true, the problems are avoided by periodically renewing the pipes, which are made of polyethylene and, currently, 80% can be recycled," adds Sánchez de Molina Peñuela, who does see a drawback in the breakdowns, which are more difficult to detect and solve when they occur underground. "That is why it is not usually implemented in urban green areas," he points out. For the expert, the basic idea is that parks and gardens should use more resilient plants adapted to the environment, which require less water.
Surface irrigation mastery
"Most of the irrigated land in the world is surface irrigated", certifies the article published in 'Agronomy', which calculates the efficiency of traditional methods, by gravity, without mechanisms or pumping, such as furrow or flood irrigation, at around 40%, and highlights their "excessive losses". A next stage of efficiency - of between 50% and 70%, according to these researchers - would be sprinkling, defined as a method involving pressurized pipes, whereby the water reaches the plants in a sort of localized rainfall.
When the sprinkler is mobile instead of fixed, we are talking about an automotive mode, which is usually based on pivot mechanisms, consisting of a huge arm with sprinklers that rotates on its axis and irrigates a circular surface. "You can see it very well on Google Earth: a green circle in the middle of a dry land; that's a pivot irrigation system," Marcos explains.
Experts say that the crops that are usually irrigated using traditional techniques, by gravity, are cereals, fodder plants and home gardens; sprinkling is used "for tubers such as potatoes"; while pivot irrigation gives "drink" to leguminous plants and industrial crops (e.g. tomato). Finally, drip ir rigation is applied to woody crops, hectares under plastic and, in general, "high value crops, because they are the most profitable and those destined for export", according to Marcos.
Water needs for the field will increase
"Net crop water requirements will increase globally by 25% by 2080, despite increased irrigation efficiency," concludes the article Implementing sustainable irrigation in water-scarce regions under the impact of climate change. "Extreme weather events such as frost, hail, heat waves, precipitation and periods of drought will affect global food security, limiting the production potential of rainfed and irrigated agricultural crops," it warns.
In this context of climate threat, agriculture faces the challenge of increasing its productivity "between 60% and 70%" to feed the Earth's population in 2050, according to Marcos. "Irrigation is six times more productive than rainfed farming, but it must be sustainable irrigation," he points out. Digitized systems, which involve localization, personalization and control are, according to the expert, key to meeting the challenges.
To this end, it is also important for farmers or food production companies to incorporate irrigation systems with more precise water and fertilizer management.
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