Inspirational ideas: Optimising irrigation in Spanish greenhouses

Sensor technology used to optimise an expensive and scarce resource: water

Sensors and irrigation control systems are a growing solution to manage water use in horticulture. These are proving to be particularly effective in Almería, Spain where you can find one of the largest concentrations of greenhouses in the world. In this arid area on the south coast, water is a very scarce and expensive resource. Francisca Ferrer, local tomato farmer, is testing a set of sensors to optimise the fertigation of her plants. This system was developed in a national project (HORTISYS) which received ERDF funding.

Francisca Ferrer and her partner have a 11,500 square metre multipurpose greenhouse where they cultivate tomatoes in soil. She collects rainwater that falls onto the greenhouse and stores it in a pond for irrigation, but as rainfall is rare, Francisca relies greatly on water from two irrigators’ associations, which is costly. The salinity levels in the water vary between the associations (electrical conductivity of 15 and 0.4 milliSiemens/cm), this adds a further irrigation challenge. “The high prices of water for irrigation also made us look into ways to optimise our use” says Francisca.

Francisca explains that the increase of agriculture in the area has led to the overexploitation of aquifers and the over-use of fertilisers, which is causing serious environmental impacts. “So we always work with the idea of improving yields whilst limiting negative effects on the surrounding environment. For this we try to be aware of the innovations available, and, when we can, we invest in them.”, says Francisca.

ParqueNat Cooperative, through which Francisca commercialises her tomatoes, was a project partner in the national experimental project HORTISYS - Remote control of greenhouse horticultural production and integration with demand-forecasting and marketing systems. Project partners also included experts in the design of greenhouses and technology companies specialised in IT and sensor systems for the agrifood industry. For 2 years, Francisca followed the tests on a sensor system developed by the project. These were carried out by ParqueNat at the experimental station of Cajamar ‘Las Palmerillas’.

Francisca Ferrer, and several other farmers, then invested in the sensor technology and are piloting its application on their own farms. The installation includes ambient sensors which record solar radiation, humidity and temperature and two types of sensors in the soil, one which measures conductivity, humidity and temperature and one which measures nitrates and potassium. “This station collects data every 6 minutes and sends this data every hour to the web. From this information online, we can identify patterns in the soil so as to meet the needs of the plant, avoiding wasting water and nutrients,” explains Francisca. In addition, she is testing fertilisers that facilitate the absorption of nutrients, another result of the project.

Francisca is happy with the results so far, “Having this data on the activity of the plants means that we can save expenses, improve production and respect the environment. We have achieved healthy and strong plants with homogeneous growth.” She goes on to say that “The sensor system proved economically viable within one growing season, and we have even gained extra revenues due to the improvement of the production”.

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