Soil scientist warns gardeners against over-treating their soil

Home gardeners may harm their soil by adding too much compost or other materials, soil scientist Alar Astover told Vikerraadio’s Huvitaja programme, ERR reports. The problem is often not a lack of something in the soil, but an excess, said Astover, who heads the Soil Sciences Department at the Estonian University of Life Sciences.

Astover suggested checking soil by lifting a spadeful, feeling it and seeing how it breaks apart. Gardeners should start investigating if plants grow poorly or appear unhealthy, he said.

Astover spoke as a new permanent exhibition, “What do I need soil for?”, opened at the Maaelu uudishimukeskus, a centre presenting an interactive exhibition about soil. Visitors can enter a soil tunnel, learn about organisms living underground and explore how plant roots communicate with one another through roots and fungal networks, including by signalling threats such as drought.

The exhibition also features listening domes with recordings of sounds from agricultural, forest and grassland soils. The recordings were made by a Swiss artist. The grassland soil is the noisiest, curator Sandra Lääne said, because it is fertile and sounds from various animals can also be heard.

Astover said soil is a complex, living ecosystem. A teaspoon of fertile topsoil, weighing about one or two grams, contains billions of microorganisms, he said. The exhibition also includes five pretend garden beds where children can pull out root vegetables to hear about factors affecting soil, as well as a tractor game.