By Christoph Kersting

Climate test facility at the Helmholtz Center for Environmental Research in Bad Lauchstädt: The building looks like a greenhouse. (picture alliance / dpa / Sebastian Willnow)

Global warming is making the weather more extreme. Scientists are studying what this means for the agriculture of the future in a world-unique field trial in Saxony-Anhalt. There they simulate the climate for the years 2070 to 2100.

“So here we see the biological realm,” explains Martin Schädler. “Wheat is for next week, you can see a thistle in between, a little poppy in between. There are only regulations regarding cultivation, so we are not allowed here with herbicides. more colorful. “

Martin Schädler gently strokes with his hand the ears of wheat which reach up to the waist on a fragmented area. And what the soil ecologist reports seems as unspectacular as the area a 20-minute drive southeast of Halle an der Saale – if it weren’t for the steel scaffolding that towers several meters high on both sides of the wheat plot.

The construction has something of a greenhouse and serves as a support for the expandable side walls and an equally movable plastic roof.

“These roofs and side panels close every night and thus increase the temperature on the plots, which corresponds to the future climate projection,” explains Martin Schädler.

A journey through time to 2070

Temperatures will rise by about two degrees on average during the year – this is the scientific consensus for much of Europe from the year 2070. And it is precisely during this trip in while Martin Schädler and his team from the Helmholtz Center for Environmental Research UFZ in Halle send the plants to his test area on the outskirts of the small town of Bad Lauchstädt.

Closing roofs and sidewalls not only artificially increases the temperature, but the areas below also receive 20% less rain – in summer, because: “There can certainly be more precipitation in spring and autumn. We’re simulating that here with this sprinkler system that we see here. “

It increases the amount of rain before and after summer by ten percent. UFZ researchers have developed a total of five such plots, each measuring 16 meters by 24 meters, along an asphalt path: In addition to organic farming, there is an area with conventional cereals, a colorful meadow with 60 species, next to it. intensive forage grazing and sheep grazing.

Exactly the same five zones are on the other side of the road, except that the plants in these plots grow in real climatic conditions: the climate of today and the broad vision of the future, almost vis-à-vis the future. -vis, which, according to Martin Schädler, is ideal for him the direct comparison between today and tomorrow is.

Significant yield losses

The test area is seven hectares in total, the largest climate simulation of its kind in the world – and it has been providing clear numbers since 2013.

“In normal years, we have yield losses in grasslands and arable fields of around 20 percent, it can be ten, but it can also be 25, compared to the non-climate-manipulated variant. that the average future yield loss is moving around ten to 25 percent, and that’s basically exactly what farmers complained about in 2018, but where you think, this will be normal, ”explains Martin Schädler.

Martin Schädler studies the consequences of the climate expected from the year 2070. (Deutschlandradio / Christoph Kersting)

Less income is one thing. According to project coordinator Schädler, the changes are most severe where they cannot be immediately seen with the naked eye: in the soil on which the plants grow. There, the number of animals such as worms, mites and springtails on the handled areas has decreased significantly, and the remaining caterpillars are also smaller than their congeners on the control areas.

Yet biodiversity is crucial for healthy soil: “There is a saying among biologists: Soil is little man’s rainforest. Quite simply because you can find thousands of species and individuals there in a few square centimeters without having to go to the tropics for something very important in the soil, because they make it fertile. This means that when a plant dies, they break it down and turn it into nutrients.

Dying soil causes problems for plants

So humus, which in turn is important for plant growth. It’s not just drought caused by rising temperatures and decreased precipitation that will disturb plants in the future. “It may just as well be that this creeping soil death has even more drastic effects on the plant in the long term,” explains Martin Schädler.

Scientists here have been able to observe developments over the years that weren’t necessarily expected. Because when it comes to soil ecology, there are also clear differences within the five usable climate-manipulated zones, emphasizes Nico Eisenhauer of the University of Leipzig, who is also researching the Bad Lauchstädt facility. .

“If we measured after a few years: How does the soil work with intensive and extensive cultivation? One would have concluded: Yes, the soil actually works a little better with the more intensive variant, probably because there are just more organic inputs for a little while and then the soil gets a boost first. like that, ”he said.

“But the more we look at the system, we find that this extensive, that is, more sustainable way of cultivating the soil is getting better and better – and has in the meantime far surpassed intensive cultivation. , for example, with extensive cultivation, we have more fungi in the soil, and they are then much better able to fix carbon in the soil, but also to be more resistant during extreme weather events. “

Flexible and diverse – the agriculture of the future

There are therefore arguments in favor of a greater focus on sustainable and ecological management, explains Martin Schädler. Overall, according to the prognosis of the soil ecologist, agriculture will certainly be different in 50 years from what it is today.

A field robot in action (Deutschlandradio / Sven Kästner) High tech in organic farming – How robots pull weeds [Audio] Organic farmers do without synthetic sprays in order to protect the environment and produce healthy food. So far, that means they’ve done a lot more manual labor than their conventional colleagues. But that does not mean that organic farmers categorically refuse technical assistance. Young farmers in particular are tech savvy and interested in digitizing agriculture. Their hopes rest, among other things, in robots that could relieve companies of tedious manual labor – without any pesticides. Sven Kästner questioned research and organic farms on the current state and outlook.

“I think it will be less predictable, and it has a lot to do with the farmer, who today is often tied to long-term supply contracts or has an economic concept based on a fixed crop rotation, a focus on certain crops – it “will have to become more flexible, more flexible in the choice of crops it cultivates and in their diversity”, explains the soil ecologist.

“Well, he can’t rely on that one great crop anymore, he can’t predict the climate for the coming year either, but he will have to make sure that if I lose the spring barley completely, I could. fortunately still have this wheat winter, which is less affected by the summer drought.