The earth beneath（在……下面） our feet is the very foundation of life. It provides us and countless（无数的） other creatures with nourishment. Yet, we're destroying it. We poison it, pour concrete over it and exploit it. A third of all fertile soil worldwide is already lost. Building it back is a challenge for humanity（人性）.

  We have to think in terms of 30 to 40, maybe even 100 years. But the potential is massive, as soil is our best hope for saving the planet. All the CO2 in the atmosphere could be captured in our soil. Even in the middle of the city, we can free up and restore soil. We don't have to seal（封） all this ground, and we should be conscientious（认真的）. But can we learn to bring the ground back to life, rather than just trampling（ 踩坏） on it?

  Styria, the green heart of Austria. Jossef Nagel is the tenth（十分之一的） generation of farmers to till these fields. He's aware that his children will also have to live off this land. So he decided to radically transform the way he farms. We used to just work（使工作） with a plough. Now this is my machine.

  His machine is a cultivator. The prongs only comb the surface of the earth. A plough, on the other hand, penetrates deeper, bringing subsoil to the top and disturbing soil life. Jossef Nagel has switched from conventional agriculture to humus farming. That means not only planting grain, rapeseed and turnips（萝卜）, but also building up humus. Humus farming gives（做） the soil more than it takes and requires new techniques.

  We loosen and mix the earth. We don't turn it anymore. When I loosen it, I make sure I don't go too deep and that I work with the smallest possible quantities. The cultivator spares worms, bacteria and fungus（真菌）. It works crop residues（残余） into the soil and thus provides food for them. Like in a compost（混合肥料） heap, the microorganisms turn plant parts into valuable soil.

  In this sense, a humus farmer nourishes the soil rather than crops. Conventional agriculture is different. Crops consume nutrients from the earth. Artificial fertiliser is added as needed. And the soil is further damaged by regular ploughing, monocultures and pesticides（杀虫剂）. This is also what Jossef Nagel was taught and how he used to farm.

  Until one day something happened which changed everything. I had a serious accident which made me change my business pretty quickly. I survived. I had a lot of guardian（[法] 监护人） angels（天使）. It got me thinking and made me decide to change how I work. Jossef Nagel was almost killed by a tree while doing forestry work.

  He was in hospital, severely injured, for a long time and began to think about what he really wanted to leave his children. They would inherit dead soil if he continued to farm as he had been. The farmer decided that if he survived, his fields would get a new lease of life as well. He found help close to his farm, where three local communities joined forces to form the ecological（ 生态的） region of Kindorf in Austria. Their aim is to rebuild humus. Gerhard Dunst is one of the pioneers（拓荒者）.

  He and fellow campaigners share knowledge in the so-called humus academy（学院） that was not previously taught in agricultural（ 农业的） colleges. Jossef Nagel and other farmers are learning how soil can be farmed to become more fertile by the year and how earthworms（[无脊椎] 蚯蚓） are valuable team members. The earth wasn't created by God but excreted（排泄） by earthworms（[无脊椎] 蚯蚓）. With enough earthworms, stones disappear. They just get buried in rainworm feces, the most stable kind of humus. Gerhard Dunst was one of the founders of the eco-region, which has since been imitated all over Europe.

  People here say agriculture needs a radical（基本的） shift in mindset. In the last decades, we mastered the art of extracting（提取） the maximum from the soil. Back then, we didn't know that the soil would get progressively（日益增多地） weaker and that more and more humus would be lost. The problem is that farmer's experience is built on this system which degrades（贬低） soil and which worked（使工作） for decades. A day at the humus academy begins with theory classes and gives farmers a chance to share experiences. Afternoons are spent out in the field where they can see, feel and smell what makes for healthy and humus-rich soil.

  Mainlois in southern Germany. A small town doing big things. Here too, the soil is to be revived（复兴）. This colossal（巨大的） building in the middle of town is the former spinning plant. The industrial ruin is the size of 20 football fields. Robert Bosch wants to change this.

  He's been mayor since 2016 but the politician from the Christian Social Union grew up here and recalls the time when the spinning（纺） factory was still in use. I remember the smell. I worked here in my school holidays between the age of 15 to 17. My job was to clear these shafts of the fluff（绒毛） that had gathered during the year. In its heyday（全盛期）, 3,000 people worked（使工作） at the spinning（纺） plant. It went bankrupt（破产的） during the economic crisis of 2008.

  Since then the old factory has been falling into disrepair and unnecessarily（不必要地） sealing（封） the soil. But Mayor Robert Bosch and landscape architect Werner Alkewitz have a plan. Alkewitz is a specialist in unsealing ground and reviving soil that was locked under concrete. He sees great potential, especially in smaller places like Mainlois. These places relied on industry. Back when it was growing, no one thought about the environment, so large areas were concreted over.

  I think there's a big potential to actively change things, like here. The will to change things in Mainlois is strong. Many of the old factory halls as well as the concrete flooring are to be gotten rid of, so that in just a few weeks rain can fall on the soil again. Right here is where we will first tear open the concrete, then we will cultivate（培养） the soil beneath. On this spot there will be a connecting path to the park. The rest will be a green area.

  We don't know what the ground is like under here because a building has stood on it for over 100 years. The plans for the town centre are represented by this model. The past can easily be lifted out and replaced with the future. The plan is to have apartments, gastronomy and offices, partly in the old halls, and plenty of green spaces. Here we have the park with the lake. The buildings have gone so the water can get back into the earth.

  The surface water will have a positive effect on the microclimate, and water will be able to drain（排水） again. This means the new town centre will be able to better withstand climate change, and the living soil will extract CO2 from the atmosphere. It's a concept that should attract public funding. The idyllic（ 田园诗的） beauty of this countryside is deceptive. Here in Ronnaburg, Thuringia, the ground is still contaminated from the GDR years when uranium（[化学] 铀） was mined here using rather reckless（不计后果的） methods. To this day the area poses a threat to human health and the environment.

  Microbiologist（微生物学家） Erika Korte and geologist（地质学家） Torsten Scheffer want to eliminate that danger, and revive the soil so that it's healthy or even useful again. They're spending a week on the site. Together with students and researchers from the University of Jena, they're investigating water, soil and plants here.