Beneath our feet lies a vibrant microbial world that drives crop health and productivity. When disrupted particularly in high-value systems like high tunnels these communities can be slow to recover. A Penn State research team led by then-doctoral candidate Laura Kaminsky and supported by former faculty member Terrence Bell worked to help farmers more effectively restore this vital underground ecosystem.

How Soil Recovered And What Slowed It Down
Kaminsky and Bell set out to explore how soil microbial communities bounce back after being cleared and what factors might hinder that recovery.  

Their experiment conducted at Penn State’s Buckhout Laboratory in 2018 and 2019 mimicked natural recolonization by adding unsterilized source soil to sterilized recipient soil. They then examined how two common challenges in high tunnel agriculture salt accumulation and excess nitrogen impacted microbial regrowth.  

The findings were clear: soils treated with salt or nitrogen experienced slower recovery and lower microbial diversity compared to untreated soils. In high tunnel systems, where salt and nitrogen buildup is common these conditions can significantly delay the return of beneficial microbes.  

High salinity slowing things down wasn’t surprising salt is a known stressor Kaminsky explained in a Penn State news article. But we didn’t expect nitrogen typically viewed as a nutrient to reduce microbial diversity. It appears to favor only a limited set of fast-growing microbes.Despite the challenges resilient microbes like Bacillus and Paenibacillus dominated early recovery and persisted across all conditions. Identifying these early colonizers may help develop soil additives to boost microbiome restoration.

Penn State’s research has laid the groundwork for a new approach to precision soil recovery enabling farmers to more efficiently restore healthy microbiomes after soil-clearing events. As high tunnels remain vital to food production, these insights provide a clear path to sustaining fertile, productive soils.  

By uncovering not just what helps soils recover, but why, the team has empowered growers to safeguard the long-term health of their land one microbe at a time.Laura Kaminsky now serves as a research scientist at Pasa Sustainable Agriculture. Terrence Bell is currently a faculty member at the University of Toronto  Scarborough, where his research focuses on developing agricultural microbial probiotics that can reliably thrive in diverse conditions, along with exploring ways to enhance microbial support for crops in urban farming environments.

Source: https://research.psu.edu/impact-story/supporting-soil-microbiomes-to-support-agriculture/