Knowledge grows through sharing
In a real-world lab in Jurapark Aargau, researchers and the local community are testing out ideas for a sustainable future. Here, knowledge flows both ways.?
2 December 2024, 6.30 P.M.
It was already dark and pouring rain, but Leander Dalbert had to know if his experiment had worked. He jumped in the car and headed over to Hof Altenberg, a farm in the Swiss village of W?lflinswil. Thick raindrops collected on the brim of his hat as the farmer rounded the cowshed. With each step, his curiosity increased, and his tread grew heavier. Just below the meadow where the cattle graze, he had dug a keyline: a 30-centimetre-deep trench designed to divert rainwater from the gravel track and spread it across the pasture. Cut along a contour line with a gradient of between one and two percent, the trench was intended to stop heavy rainfall from washing away the access road.
Sure enough, the trench had done its job, slowing the flow and guiding the rainwater into the empty holes dug to plant pear trees. As well as miti?gating downpours and drought, keyline design also underpins a neat agroforestry system. Along the trench, saplings of hazel, cornelian cherry and almond have been planted among herbs and berry bushes, where they loosen compacted soil and promote rainwater infiltration. At the same time, this line of vegetation forms a fodder-tree hedgerow at the edge of the pasture, along with sundry vege?tables. The dense planting produces a diverse harvest and keeps the ditch behind from being overrun with weeds.
Sustainable by design
Out in the field
Inspired by keyline pioneers Philipp Gerhardt and Katja Degonda, Dalbert’s rainfall management experiment is part of the Jurapark Aargau Real-World Lab – a joint initiative between the ETH Domain and the Jurapark Aargau regional nature park, with funding from the ETH Board. In this real-world laboratory, researchers from ETH, the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and the Swiss Federal Laboratories for Materials Science and Technology (Empa) team up with the local community to trial practical ideas for sustainability in agriculture and beyond. Several workshops have given rise to four real-world experiments in water management, climate adaptation and the circular economy. Dalbert’s scheme is exploring the use of keyline design for smallholdings.
“I love how this project aligns so closely with local interests,” says WSL environmental engineer Anna Leuteritz. It’s now June, and she is here with WSL hydrologist Manfred St?hli and commu?nity service volunteer Laurin Nüesch to make an initial inspection of Dalbert’s keyline. Measurements will show whether it has improved the soil’s water-holding capacity. After a brief discussion about sampling locations, the three grab spades, mallets and a box of tools. Soon, energetic blows are ringing out across the meadow as Leuteritz hammers the hole-cutter into the turf. A skilfully inserted spade then frees the metal cylinder from the soil. Nüesch eases out the sample with a knife and stows it away in a plastic bag. This will be analysed later in the lab to determine moisture content and soil composition.
Ten days earlier, St?hli’s team had installed a weather station complete with 20 sensors, sunk to a depth of 10 or 50 centimetres. Every 10 minutes, these measure parameters such as soil water potential, moisture content, temperature and electric?al conductivity. Further instruments provided by Eawag record the groundwater level. In the shadow of the team vehicle’s raised tailgate, St?hli scrolls through smartphone graphs of soil water potential plotted against time and weather. “I’m really curious to see what impact the keyline trench will have,” he says. He too first encountered keyline design at the real-world lab here in Jurapark Aargau, and he’s now eager to explore its potential by setting up another keyline experiment this autumn on a test site near the WSL headquarter. While Leuteritz logs the GPS data for the soil samples, St?hli and Nüesch load the equipment into the car. For today, the measurements are complete. They jump in and head off to the next farm, 25 minutes up the road.
Graceful curves
On the way, they have time to take in the rich landscape of Jurapark Aargau. Traditional orchards, full of mature trees, are interspersed with vineyards and cornfields. Above, the hilltops are mainly crowned with woodland. Dalbert is not the only one here grappling with climate change and water-management issues. Because the region straddles the Table Jura and Folded Jura, Jurapark’s soils are generally shallow. They dry out quickly in hot weather and cannot absorb heavy rainfall fast enough to prevent surface run-off and resulting erosion. Keyline design is one way to prevent run-off and improve the retention, distribution and infiltration of rainwater.
Hof ?bertsmatt, a farm in nearby Ober?b?zberg, has already installed a larger-scale water management system. Here, the aesthetics of keyline design are immediately evident: rows of trees hug the hilltop in graceful curves, punctuated periodically by heaps of stones and branches that provide a habitat for small animals. In place of ditches, the Treier family uses embankments – 20 to 30 centimetres high and topped by fruit and forest trees – to retain rainwater. To ensure the land remains accessible to machinery, the embankments deviate slightly from the actual contour lines and are separated from one another by broad swathes of pasture.
Drone mapping
Arriving shortly after the WSL vehicle, a shiny metallic BMW pulls up noisily in the gravel yard. Two young men wearing baseball caps jump out and flip open the boot lid. Inside is a drone, 70 centimetres in height, its rotors neatly folded away in a padded compartment for safe transport. St?hli has asked Derek Houtz and Lars Horvath, co-founders of the WSL spin-off TerraRad, to fly their drone over the site. It carries a microwave radi?ometer that measures soil moisture to a depth of 10 centimetres.
After consultation with the team, Horvath plots the flight path on his laptop and picks up the remote control. In just 10 minutes, the drone has completed its job. Houtz then uses his mobile phone to view a detailed map of the soil’s moisture content, derived from data collected by the drone. A first look shows increased water content in the vicinity of the keyline, a finding that St?hli and Leuteritz hope to later confirm with other measurements. They are especially interested in what topographical patterns might emerge in the images.
TerraRad was founded in 2020, during the first wave of the Covid pandemic. Aerospace engineer Houtz had long cherished the idea of equipping a drone with the remote-sensing technology usually carried by satellites, the idea being to obtain images of a higher resolution than those available from space. So, using the enforced lockdown to his advantage, he set about building suitable instruments at home. After an initial publication on this topic, he was soon fielding calls from researchers keen to use the technology in their own projects. “Our job is to turn the drone into a trusted means of measuring soil moisture,” Houtz explains. Here, in the Jurapark Aargau real-world lab, TerraRad can explore how the drone might best be used for field work and agriculture. Alongside science and research, top clients include golf courses, which use the sensor technology for targeted irrigation.
Research for real life
In a real-world lab, knowledge flows both ways: while researchers learn about local needs and life in the field, farmers get access to valuable data and expertise. “We’re all equals here!” says Philipp Lischer from ETH Zurich. Together with Tim Geiges from WSL, he is head of the real-world lab. Barely a month goes by without the pair holding a site visit to one of the ongoing experiments to check on progress or discuss where fine tweaks might be made. These visits foster dialogue with the local community and ensure that the research projects dovetail neatly with practical real-?world needs.
These moments also illustrate how the real-world lab is forging new networks. With new contacts and the infrastructure firmly in place, St?hli will be able to offer doctoral projects in keyline design next year. In the meantime, this Autumn Semester will see ETH students of landscape architecture and agricultural sciences get involved in the current keyline project. They will draw up keyline designs for farms and other businesses in Jurapark Aargau and explore the political and social obstacles that stand in the way of such work.
Just as a keyline diverts rainwater along different routes, so the real-world lab is forging new paths in the production of knowledge. By bringing together the expertise of various ETH Domain institutes and applying it to real-life situations, it “can help reinforce trust in the academic world,” says Dalbert, reflecting on his experience with the lab. In the farming community, he often hears that studying is a waste of time. Yet the real-world lab can help debunk this myth – and perhaps encourage farmers to view collaboration with science and research as the route to success.