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Intelligent irrigation protects the environment

Farmers can save large amounts of water without adversely affecting crops during dry periods. A large, new EU project will develop technologies that make this a practical possibility on individual farms. The technology can also reduce the losses of nitrogen to the aquatic environment.

[Translate to English:] Vand er en dyrebare ressource og der kan spares meget på den ved at vande intellligent. Ny forskning viser vej. Foto: Janne Hansen

For weeks this summer, the sun baked the landscape to a crisp. Very little rain, combined with high temperatures and strong winds meant that in some places, the soil, animals and plants were thirsty for water. To avoid damage to their crops, farmers irrigated their fields - but during dry periods, water is a scarce resource that must be used carefully.


A large, new EU project, with researchers from Aarhus University among the participants, will enable water use on individual farms to be reduced considerably. This will be achieved by developing a system that will enable farmers to irrigate effectively and precisely, exactly and exclusively at the places where there is a need. Some of the tools are sensors that can measure whether crops are thriving, growth models, meteorological data and state-of-the-art irrigation systems.


The four-year project has participants from universities, research institutes, private industry, FAO, trade bodies and authorities from Denmark, Holland, Spain, United Kingdom, Portugal, Italy and Greece. The project has been awarded six million Euros (44.7 million Danish crowns) from the EU's 7th Framework Programme (FP7).


Measuring the water demand of crops


The project will develop a decision support system for use by individual farmers, so irrigation can be undertaken economically and effectively on single farms - that is to say, precisely where and when the crops need it.


The system will use information concerning the soil type, fertilisation and water quality, together with data collected from monitoring equipment and weather forecasts. Researchers in the different countries will work with selected water-demanding, high-value crops such as tomatoes, cotton, maize, grapes, citrus fruits and potatoes. Given the nature of countries participating in the project, a wide range of climatic conditions and soil types will be covered.


In the Danish part of the project, researchers will focus on potatoes. Researchers will combine knowledge  of the potato plant's need for irrigation at different stages, with measurements of the potato plant's growth to feed growth models with data, so that they can generate robust predictions and advise farmers.


Sensors will measure the condition of the plants, amongst other things by measuring leaf area. The data is sent electronically from the field to the computer or mobile phone - or satellite images of the field can be sent. On the basis of the leaf area, growth models can calculate the biomass of the crop and thereby judge whether the plants are growing better or worse than in an average year. Data from sensors measuring the water content of the soil and the local weather conditions will also be taken into account, to create a comprehensive picture of whether the crop needs water.



- Up to now, these sensors and models have only been used by researchers. Now we will see if these models work in practice, says professor Mathias Neumann Andersen from the Department of Agroecology at Aarhus University.


Measuring the nutrient demand

Love and spring water are not enough - not even for crops. They also need nutrients but farmers have to take care not to apply them in excess, as this can have negative effects on the environment. The project therefore includes experiments with demand-driven applications of nitrogen via the irrigation system.


- If one has knowledge of the crop's growth conditions and well-being, irrigation and fertilisation can be adapted to these conditions. This way, one can save water and nitrogen, without risking a loss of yield. All things being equal, a more targeted application of water and nitrogen will also reduce nitrate leaching, points out Mathias Neumann Andersen.


Sensor technology also plays a role here, via new tractor-mounted equipment for measuring plant growth and nitrogen content from the firm Agrosens. A type of sensor - a laser - scans the leaf area as described earlier in this article. Another type of sensor measures the light that is reflected from the leaves across a range of wavelengths, enabling the nitrogen content to be determined. The more blue-green the colour in the light reflected from a given leaf area, the greater the plant's nitrogen content.


More water-value for the money

It sounds very specious to be able to apply water and nutrients exactly there where the field needs it but this demands a precision irrigation system. That is normally more expensive to construct than a common raingun. Which solution is the most profitable, seen in the wider perspective?


Researchers will also answer that question in the project. At Jyndevad Experimental Station, a large field trial with potatoes has been established, where drip irrigation is compared with raingun irrigation under Danish conditions.


- Drip irrigation is more expensive to install but the cost might be recovered if one can irrigate less, apply nitrogen continuously according to demand and achieve a higher yield and a better quality. That could probably provide extra income, says Mathias Neumann Andersen.



Read more about the EU project “Flexible and Precision Irrigation Platform to Improve Farm Scale Water Productivity” (Figaro) here


Further information: Professor Mathias Neumann Andersen, Department of Agroecology, e-mail: mathiasn.andersen@agrsci.dk, Tel: +4587157739, mobile: +4522400742