Our population is steadily growing and because of that, we need new ideas to produce enough food for everyone. To produce sufficiently food, we need enough soil, but this is the problem. The available ground is becoming less. One solution for this problem would be "urban gardening and urban farming". This means, that we can practise agriculture on the roofs of houses in parks etc.
Here you can find some articles about urban farming and urband gardening. On my view, this would be a good topic for our project.
Kleingärten: Die Landwirtschaft zieht in die Stadt (bafu.admin.ch, 2012)
https://www.umweltdialog.de/de/verbraucher/lebensmittel/2018/Urban-Farming-Gaertnern-in-der-Grossstadt.php
https://www.tagesanzeiger.ch/zuerich/stadt/zuercher-startup-baut-europas-groesste-urban-farm/story/24877447
https://www.srf.ch/sendungen/10vor10/die-idee-urban-farming-im-grossen-stil
Tamara Keller, BM2 Teilzeit 2019