North American Soils Analysis Yields New Research Guidelines and Continental-Scale Patterns

Just as most of an iceberg stays hidden under the surface of the ocean, many of the most important ecosystem processes happen underfoot. Soil properties, processes and organisms play key roles in everything from climate change to crop growth to clean water and natural disasters.

The National Ecological Observatory Network will be sampling an enormous variety of soils across the U.S. Soil conditions and types vary widely even within a small plot of land, and NEON needs to perform consistent and representative soil measurements at each of its 60 terrestrial sites throughout the network's 30-year lifetime. Optimizing these measurements requires a strategic, quantitative approach. The payoff is new opportunities to study and understand soils and their impact on ecology and natural resources across the country.

In a recent open-access paper published in PLoS ONE, NEON scientists present the results of a continental-scale soil analysis that demonstrates some of the power of consistent, large-scale sampling.

Soil sampling analyses like this one have never before been conducted at this scale. NEON scientists went on a whirlwind tour of 60 NEON field sites and collected hundreds of evenly spaced soil temperature and moisture measurements at each site. They found new evidence of emergent, continental-scale patterns in soil variability, patterns that earlier studies with fewer sites and inconsistent sampling methods couldn't identify.

In addition, NEON scientists used this large body of standardized soil data to demonstrate how NEON sites provide a remarkably representative snapshot of U.S. soils. In the process of using the data to optimize NEON soil sampling, the scientists developed a tool that could help other researchers plan soil sampling campaigns in the U.S. They were also able to test a few hypotheses about soil variability, with some surprising results.

Soil is a reservoir for moisture, nutrients, and hardworking micro-organisms that play a major role in recycling the nutrients necessary to grow plant life and feed animals and plants alike above ground. As part of its mission to collect and provide standardized ecological data from across the United States, NEON will regularly observe and measure soil microbes, belowground root biomass, and the chemical and physical conditions of soil at each of its 60 terrestrial sites.

NEON scientists Hank Loescher, Ed Ayres and Hongyan Luo are coauthors on the PLoS paper, along with former NEON field technician Max Brunke.