Nutritious and tasty are the chard and cherry tomatoes that a team of engineers from our University managed to produce using seawater without desalination in the coastal sector of the Atacama desert, in the Antofagasta Region.
The development corresponds to a pioneering project that can revolutionize food production in the country, and transform this alternative into a new productive activity that will directly benefit the inhabitants of coves and populated areas in the north.
The particularity of the system is the use of seawater directly, that is, without eliminating the salt that incorporates the vital element from its oceanic origin. This achievement was possible thanks to a development carried out by a team of engineers from the Center for Technological Research on Water in the Desert (Ceitsaza) of the UCN, a center specialized in the management and search for solutions to problems related to water resources.
The idea, which was presented to the community and authorities of the area, consisted of a study of the technical feasibility of growing chard and cherry tomatoes with seawater, using capillary irrigation.
“Capillary rise is a property of liquids. The water begins to rise and the salts are retained in the substrate ”, says Natalia Gutiérrez Roa, Project Director, who explains the basic principles of the methodology used to grow the vegetables.
To carry out the study, which took place in coastal facilities of the UCN, two cultivation terraces were built for tests, with three levels of different heights each.
The first level considered 40 centimeters of substrate, the second 80 and the last 110 centimeters. Each terrace designed by the engineering team incorporated a seawater phreatic level at its bases.
In the case of chard, the best results were obtained in the first level (40 cm.), With plants whose growth was between 22 and 52 cm in height. Regarding cherry tomatoes, the outstanding results were at level 3 (110 cms.), With plants that reached 46 to 72 cms. Tall.
"We chose chard and cherry tomatoes for their tolerance to salinity, although a basic principle of this project was not to irrigate directly with seawater in a superficial way", clarified the agronomist Natalia Gutiérrez.
The development of the project had a total cost of 34 million pesos, contributed by the Foundation for Agrarian Innovation (FIA) and the UCN.
The harvested vegetables, in addition to a pleasant taste and texture, showed significant amounts of minerals beneficial to health, such as potassium, calcium and iron, among others, to which were added high levels of dietary fiber and proteins, mainly in the case of The chard.
Another of the singularities of the project is the use of accessible materials, such as waterproof plastic and concrete, those that have low cost and that are easy to obtain and install by potential users of this type of technology.
The development of technologies, the generation of knowledge and the use of the potential of seawater as an unconventional source of water for agricultural use, was one of the main achievements of the project.
Although the water obtained directly from the ocean shows a high content of salts, with an approximate salinity of 35 grams per liter, determined mainly by sodium chloride, which causes water stress in plants, the possibility of using this resource in agriculture is becoming more feasible every day.
According to the Business and Technological Development Manager of Ceitsaza, Yaneska Tapia Lineros, the idea is to continue with a second stage, which involves the installation of terraces and starting the production of vegetables in the Caleta Constitución sector, a fishing community located in the Mejillones peninsula, in the Antofagasta Region.
The idea of the researchers is to transfer this knowledge to the inhabitants of the place, so that they have the possibility of evaluating the system and adding another productive alternative to their traditional work related to the ocean. "This experience can be replicated in other coves and coastal areas of the region, as well as in other parts of the country," highlighted Yaneska Tapia.
He also raised the possibility of opening the productive field to other plant species, such as quinoa or basil, which could have good results in the area.
For the Ceitsaza team, growing agriculture on the region's coastline is a certain possibility that should be considered in a territory characterized by its extreme aridity.
Although the engineers argue that irrigation is one of the great pending issues in Antofagasta, mainly due to the water stress generated by the few existing sources of fresh water, the constant increase in demand for food and population growth make it essential to address alternatives not conventional. The above is essential to satisfy consumption and provide new alternatives to its inhabitants.
The Ceitsaza team of engineers highlights that although the use of seawater is already used in agriculture in nations such as Spain and Israel, in Chile its use is still very limited and is just in the testing phases, with the Antofagasta Region being the area that leads this line of research in the country.
They add that since 2011, the Center has developed projects in the agricultural field, to support producers in the area and contribute with solutions that benefit the community.
In the materialization of this work, the contribution of the thesis student of the Environmental Civil Engineering career, Alexandra Astorga Sánchez, who joined the female team of the project, also highlighted.
The contribution of the future professional constitutes a precedent, since it marks a growing interest of the new generations to participate and be part of investigations that were unthinkable a few years ago, and which will have a great impact on the development of the North of Chile in the coming decades.