Friday, 22 August 2025, 19:46
The abundant rainfall so far this hydrological year has put an end to almost five years of extreme drought in Malaga province, which has been particularly severe in the Axarquia area. Hundreds of hectares of subtropical crops, especially avocados and, to a lesser extent, mangoes, were badly affected by the drought. Many farmers have opted to renew their crops now that the rains have returned and the farming outlook is once again promising.
The use of reclaimed water has made it possible to offset the drastic reduction in water resources to the area from La Viñuela reservoir, which was shut off from 1 October 2022 until last summer, when three million cubic metres were allocated for emergency irrigation.
This year, the situation is completely different, with 12.8 million cubic metres planned for the Guaro Plan irrigated area, which means some 2,000 cubic metres of water per hectare.
The project seeks the best formula to optimise the available water, whether from the reservoir, wells or reclaimed water
Given this difficult situation, the efficient use of water resources has become one of the major challenges for the governing authorities and farmers. In this context, the Malaga-based company Bioazul has spent several years designing applications and carrying out field studies to find the best formula for optimising available water, whether from reservoirs, wells or reclaimed water.
Specifically, in response to the challenges arising from climate change, Bioazul has set up a research laboratory, dubbed the ‘Living Lab’, a research and development space that has enabled it to create and test technological solutions to optimise water use and improve crop sustainability, with a special focus on the Axarquía area.
The so-called ‘sustainable Axarquía task force’, led by Bioazul together with Trops (the Vélez-based farming cooperative), the La Mayora institute of subtropical and Mediterranean horticulture (IHSM, part of Spain’s national research council – CSIC), the University of Malaga (UMA) and Algarrobo’s irrigation community, has completed its work, after 24 months of intense activity, and has now presented the main results of the project, which are available in the new section of its website https://axarquiasostenible.es .
Impact of climate change
The project was conceived with a clear objective: to promote the sustainable use of reclaimed water in agriculture in the Axarquía area, in a context marked by water scarcity, the impact of climate change and the need to improve the efficiency of irrigation and fertilisation.
By way of example, La Viñuela reservoir, the main source of water for irrigation in the area, was at 9.7% of its capacity in 2023, reflecting the seriousness of the problem for the sustainability of the agricultural sector in the area.
The task force’s proposal focused on harnessing the nutritional content of reclaimed water to reduce the use of mineral fertilisers, improve profitability and minimise environmental impacts, especially in subtropical crops such as avocado, mango, dragon fruit and passion fruit.
The main results of the project include the development and validation of a free application for the management of fertigation (injecting water-soluble fertilisers into the irrigation system), accessible at https://axarquiasostenibleapp.com/login. This application makes it possible to calculate the nutritional needs of avocado and mango crops, adjusting them according to the quality of the available reclaimed water and optimising the use of water and mineral fertilisers.
Irrigation with reclaimed water allowed the crop to grow without applying fertilisers and with virtually no physiological imbalances
They successfully implemented a precision irrigation system with sensors in a greenhouse and developed a digital platform for irrigation control adapted to the use of reclaimed water in dragon fruit and passion fruit crops.
“Monitoring the water and nutritional status of the crops has made it possible to verify that the established irrigation guidelines and the fertilisation used have been adapted very well to the plants’ needs,” said Bioazul in a statement.
Irrigation with reclaimed water allowed the crop to grow without the application of mineral fertilisers and with virtually no physiological imbalances, at least in passion fruit cultivation, thanks to its high content of essential nutrients, which represents a potential saving for the farmer.
The initiative has confirmed the “good adaptation of dragon and passion fruits to the grown-in-pots environment and the agronomic management implemented, especially regarding irrigation.” Thus, the plants showed no signs of water imbalance and drainage levels were adequate, according to those supporting the research project.
Absence of heavy metals
Specifically, in passion fruit, measurements of stomatal conductance (gas exchange of, for instance, carbon dioxide for oxygen) and water potential showed some water stress in plants irrigated with reclaimed water, although their development was not compromised.
At the nutritional level, foliar analyses did not detect any relevant deficiencies or harmful accumulations in passion fruit, highlighting the absence of heavy metals and an adequate concentration of key nutrients, even without the application of fertilisers in the reclaimed water treatment.
Similar analyses were carried out on dragon fruit, including the study of water and nutrient content in different sections of the cladode (the photosynthetic leaf). As with passion fruit, irrigation with reclaimed water “proved to be feasible without notable, negative physiological consequences”.
Comparative data analysis has shown that reclaimed water may contain certain ions such as sodium, which could be harmful to some plant species if not properly managed. The energy study conducted and the proposed solar photovoltaic installation on the experimental plot of land would allow for a 57% reduction in the regeneration system’s energy consumption, with a 46% saving in electricity costs and a payback period of between 5.7 and 7.7 years.
A cost-benefit analysis shows that the proposed model for urban wastewater treatment and reuse in the eastern part of the Axarquía “is technically, agronomically and economically feasible, provided that appropriate conditions such as scalability, price adjustments and incentives are in place”.
In other words, by scaling up treatment capacity to 150 cubic metres/day, the price per cubic metre would be significantly reduced to 0.27 euros/cubic metre. The researchers highlighted “the alignment of this strategy with the current regulatory frameworks (Royal Decree 1085/2024 and EU Regulation 2020/741) and with the principles of the circular economy and adaptation to climate change”.
The group carried out intensive communication, dissemination and knowledge transfer work
This research group also carried out intense communication, dissemination and knowledge transfer work, which included more than 1,000 website visits, over 460 social media followers, 128 publications in the media and on digital platforms, 15 networking events, five technical visits to the experimental plot of land, three technical workshops and two training workshops, with more than 150 participants. The promoters have also produced newsletters, training material and an EIP-Agri technical factsheet.
As part of the project, a video-report was produced and is available online. With these results, the task force believes that it “demonstrates that it is possible to move towards a more efficient, sustainable and profitable agriculture through the use of reclaimed water, technological innovation and the involvement of the local productive sector” in the Axarquía.
The technical reports, the digital tool, the cost-benefit analysis and all the materials are available on the project’s website, https://axarquiasostenible.es.
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