From theory to practice
Irrigation research improves water productivity in Chile.
By Anna Mouton
Dr Samuel Ortega-Farias is the director of the Research and Extension Centre for Irrigation and Agroclimatology and a professor in the School of Agronomy in the Faculty of Agricultural Sciences at the University of Talca in Chile.
He specialises in modelling evapotranspiration, plant-water status, and irrigation management using remote sensing. His current projects focus on applying technologies such as drones and satellite-based sensors to improve sustainable water use and water productivity.
At the 2023 ISHS Irrigation Symposium in Stellenbosch, Ortega-Farias participated in a panel discussion about bridging the gap between irrigation theory and practice. He shared some of his views on the topic in a recent interview.
Q What are the current trends in irrigation in Chile?
A Many farmers are moving to drip irrigation. I think drip irrigation has big advantages, and in the future, much of our production will be drip irrigated.
New plantations for fruit or wine production are drip irrigated because we save a lot of water. Even corn, tomatoes and potatoes are moving to drip irrigation – I calculated that furrow irrigation of corn requires 21 000 m3
of water per hectare per season, but drip irrigation requires only 9 000 m3.
The other advantage of drip irrigation is that you can apply the right amount of fertiliser. And you save labour – you don’t need as many people in the fields.
Q How do you collaborate with industry?
A Our group works in applied research. We work very closely with companies [larger growers or groupings] to adjust and calibrate the technologies in the field, and then we give them to the [smaller] farmers.
Right now, in Chile, we are having a big drought. So, companies are moving very fast to adopt new technologies. For example, I’m working with Concho Y Toro, the largest winery in Chile. [Concho Y Toro has more than 10 000 ha under cultivation in Chile, Argentina, and the US].
They came to me to improve their irrigation management. I said we can use satellites, weather stations, and soil sensors, but who in your company is going to use the technology? So, the manager in charge of the irrigation is doing a PhD with me.
In one year, he applied some basic techniques to about 500 ha and reduced the water application by 30%. They have expanded it to 3 000 ha and developed a software platform – they can access all the irrigation requirements on an iPhone. I have another PhD candidate who is doing the same on cherries.
I’m also working with Ferrero [the world’s second-biggest chocolate producer and maker of Nutella] to develop an irrigation management system for hazelnuts. You need to have the right irrigation design and do studies to decide how many lines and drippers you need per tree. For example, we use four dripper lines for hazelnuts.
This collaboration strategy is good because we also learn a lot. I have a lot of scientific knowledge, but I don’t know the specific practical issues when growing a crop. It’s much better when you interact with farmers and agronomists from the companies.
Q What have been barriers to the adoption of new technology?
A During the past 20 years that I have worked here in Chile, we have introduced different types of technology in fruit and wine production, and we were able to reduce the water application by 30 – 80% without affecting yields. The big problem at first was that we would give the technology to the farmers, but they didn’t know how to use it. So, we had to do a lot of training.
When you move from furrow to drip irrigation, you reduce the water application, but the farmers didn’t use any techniques to estimate the amount of water they need to apply. And the government gave irrigation systems to the small farmers, but they didn’t teach the farmers how to use them. So, they used them for a month or two and then went back to furrow irrigation.
Another key issue with the small farmers was energy. When we told them to put in drip irrigation, they complained that they needed energy. Right now, energy is also becoming a big problem here. So now the government is funding drip irrigation with solar panels. But again, if the farmers have problems with electricity from the solar panel, they stop using it.
We have a problem with the small farmers because they are less educated, and it’s a little difficult for them to grasp the technology. The right strategy is to give farmers technology plus the right training.
Q What is the role of student training?
A You need to teach the students theory,but you also need to teach them how to use the theory. And sometimes, the university is one of our biggest problems.
We are lucky because our university is in the countryside in a region which produces wine, fruit, and other crops. So, we have the opportunity to take the students to the field. Some students like irrigation. I work with those students and teach them how to use sensors, weather stations, and drones and to analyse data from satellite images.
Q Do you think there is existing scientific knowledge that could be better applied?
A Absolutely. In Chile, we have all the latest technology. We have so much data in Chile now – you can go to the internet and get satellite images. But people aren’t able to transform the data into knowledge. Economically relevant knowledge – this is a key point.
And in my lab, we have done a lot of research in the past 20 years. Now, we must take this technology and try to develop some kind of software platform for irrigation management.
You can have pure research that gives you very nice data that you publish in scientific papers. However, it is crucial to transform these articles into technical tools that allow farmers to carry out sustainable irrigation management in their orchards and vineyards. This is the big challenge now.
BOX
Drip makes a comeback
Drip irrigation had a shaky start in the South African apple industry. But now, more and more growers are embracing its benefits, as illustrated by two case studies on the following pages. We also have two articles on irrigation that originally appeared in English in Fresh Quarterly, the Hortgro Science technical magazine. The relevant issue focuses on climate change and irrigation. For a free digital copy, visit www.freshquarterly.co.za.
Drup is terug
Drupbesproeiing het ’n wankelrige begin in die Suid-Afrikaanse appelbedryf gehad. Al meer produsente begin egter nou die voordele daarvan ontdek, soos beskryf in twee gevallestudies in hierdie uitgawe. Ons het ook twee besproeiingsartikels wat oorspronklik in Engels in Fresh Quarterly, Hortgro Science se tegniese tydskrif, verskyn het. Die betrokke uitgawe fokus op klimaatsverandering en besproeiing. Vir ’n gratis digitale eksemplaar, besoek www.freshquarterly.co.za.
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