Spain: Desalinated water to irrigate Almería greenhouses
Differences in agronomic and economic productivity of tomato, watermelon, pepper and zucchini were analyzed, according to the use of well water versus desalinated water, by researchers from the University of Almería.
Their main conclusion has been that it is profitable to use desalinated water for irrigation in greenhouses since it has caused increases in production, also improving the uniformity in the quality parameters of crops.
For decades, the Almería greenhouses have been the true engine for socio-economic and demographic development in many of its areas. Annually the 31,000 hectares of greenhouses produce more than 3 million tons of fruits and vegetables, generating a value of almost €2 billion; more than 76% of the production is exported.
The Almería model is a success story that, nevertheless, presents three pressing problems: downward pressure on prices, water and waste management.
The current study focused on the water problem in one of the most arid regions of Europe.
The efficiency in water use is high in the greenhouse area but however the average annual consumption per hectare is close to 5,000 cubic meters, of which 80% come from the subsoil; this causes an annual water deficit of 170 cubic hectometers. There has been a pressure on water resources causing problems of noticeable lowering of the water table and aquifers salinization.
The sustainability of the province water resources goes through the use of desalinated, reclaimed and runoff water.
Of these thee water sources, considering the available volume in Almería, desalinated seawater stands out. Almería has two desalination plants, one in Carboneras, with annual distribution capacity of 42 cubic hectometers, and the other in Campo de Dalías, with 30.1 cubic hectometers.
The main objective of the study was to analyze the differences in agronomic and economic productivity with the promised results above cited.
For an extended use of desalinated seawater, the authors indicated that the main problems lies in its price, which is 0.53 €/cubic meter. They consider 0.30 €/cubic meter a reasonable price.
Energy consumption is the main factor that contributes to such a high price of water. The study’s authors believe that, with technological improvement and the inclusion of renewable energies, the energy consumption for desalination can be considerably reduced.
Find full study in Spanish here