Soil transplantation may help areas needing nature restoration, according to a study published in the Journal of Applied Ecology. The global results were collected by an international team coordinated by researchers from the Netherlands Institute of Ecology (NIOO-KNAW) and included data from 46 field experiments conducted across 17 countries on four continents.
There is an urgent need to find effective soil restoration methods, but researchers are still unsure what works. In many places, the answer may involve a soil transplant coming from areas with healthier soils. The principle is simple: areas with healthy soil and associated with a high diversity of soil life and plant seeds can “make a donation” to poorer areas where the soil is degraded. After the soil transplant, natural life can recover at a faster pace, sustained by healthy soil. A team from NIOO has already tested the efficacy of this approach in the Netherlands using a thin layer of healthy soil. Now, with the help of an internation team, they want to find out how this would work in other types of soil.
Results from multiple experiments show that transplantation works in many different situations. “From the tropics to the tundras, soil transplantation substantially improves the chances of restoring vegetation with species of high conservation value,” explained Jasper Wubs, who coordinated this project. “Particularly if it’s applied over larger spatial areas.”
After the soil transplant — which includes a variety of beneficial soil organisms — vegetation can blossom both in terms of quantity and diversity. However, the team found some differences in how the soils reacted long-term. The best results were found in loamy soils and when the treatment was implemented in areas larger than 180m2.
The researchers believe this approach can be an effective tool for soil restoration. “We are now better able to restore biodiverse ecosystems in places where natural regeneration is not enough,” said Wubs. “At the same time, our analysis shows that we need to figure out why restoration is more successful in some cases than in others. The glass is half full, but it could be fuller.”
This work comes at a crucial time. The United Nations has declared a Decade of Ecosystem Restoration, and the European Union is developing a Nature Restoration Law. These initiatives need effective restoration measures — such as soil transplantation — to be successful. “Ecological recovery is tricky and often unpredictable,” concluded Wubs. “People usually only look at aboveground recovery, but we have demonstrated that the groundwork for success is laid below ground.”
Gerrits G, Waenink R, Aradottir A et al. (2023) Synthesis on the effectiveness of soil translocation for plant community restoration. Journal of Applied Ecology, https://doi.org/10.1111/1365-2664.14364