Much More than Dirt

Posted on Thursday, June 30th, 2016

Written by Emma Drake, Communications Summer Intern

Small plants grow in the top of a lysimeter core.

Parents despair when their children come home covered in it, their bright white t-shirts turned into brown camouflage prints.

Dirt.

More precisely, as many environmental scientists insist – soil. The brown layer of earth that is often swept off floors and washed out of clothes actually plays a vital role in producing food and protecting the environment.

Soils are integral to the sustainable production of crops for food and feed. Soils provide benefits such as water filtration, nutrient cycling and biodiversity support as well as the physical structure required for plant growth.

Despite these benefits, soils are sometimes overworked in agriculture, as farmers are tasked with feeding an increasing population among other pressures. Poor soil and crop management strategies can degrade the soils’ structural qualities and deteriorate their ability to provide these services to the surrounding ecosystem.

To protect this valuable resource, researchers in the School of Environmental Science are seeking a deeper understanding of soils and soil ecosystem services and exploring how management practices can be altered to best support soil health.

Prof. Claudia Wagner-Riddle and her team of research scientists have begun work on a project to measure soil health under different crop management strategies and climate change. They have hypothesized that by increasing the diversity of plants on the field and maintaining ground cover through the use of cover crops, the soil health will improve.

The project will begin gathering data in 2017 and will run over a 20-year period.

High-Tech Equipment

To collect the data, the researchers are using highly advanced devices called lysimeters. Lysimeters are large steel cylinders that surround undisturbed soil cores and are equipped with multiple sensors at various depths. The data collected from these lysimeters is sent to data loggers that will then be analyzed by the research team. The research team acquired eighteen lysimeters from the German company UMS, represented by Hoskin Scientific in Canada, with funding from the Canadian Foundation for Innovation (CFI) and the Ministry of Research and Innovation (MRI).

Working with this cutting-edge precision equipment is very exciting for the research team.

“There are only 200 of these in the world,” shares Sean Jordan, a research technician working on the project. “To have eighteen of them here is pretty amazing.”

Worker guides an excavator to extract a soil core.
A worker helps guide the excavator while extracting soil cores in Elora.

The Set-up

In May the research team extracted the eighteen undisturbed soil cores from field sites in Elora and Cambridge, Ontario. Nine cores were taken from each site. The cores from Elora provided a loam soil, while those from Cambridge are sandy soils. Weighing approximately three tonnes each, the cores are being placed in concrete shafts at an additional location in Elora.

The cores and shafts are open-topped. Once the lysimeters cores are placed in the concrete shafts, the top of the core will be level with the research field. This allows the soil cores in the lysimeters to be cropped as usual across the field, which will begin in soybeans this summer. The shafts are also closed-bottomed. This is important as it maintains the closed-environment conditions necessary to conduct research and collect accurate data.

The cores will be placed in groups of six throughout the field, providing three side-by-side comparisons. The effects of the various agronomic practices on soil health will be analyzed from the lysimeter data and compared across the three groups.

Concrete shafts in the ground at the Elora research site.
The lysimeters will be placed in these concrete shafts at the Elora research site.

Multidisciplinary Methods

The set up is high-tech, high precision and focused on a multidisciplinary approach.

“Traditionally these types of infrastructure have focused on mostly one component but we are trying to look at several of these environmental issues and how they are related,” explains Claudia.

For example, past projects with lysimeters have focused solely on water in soils. By weighing the cores and measuring how much water filters to the bottom, water loss through the top via evapotranspiration can also be estimated, explains Claudia. This is where other projects may have stopped, but Claudia’s team is taking it many steps further.

In addition to water use, carbon storage and greenhouse gas emission data will be collected and interpreted into collaborative models that demonstrate how soil health changes under agronomic practices and climate change. The team will also measure indicators of organic matter and relate them to microbial communities. 

“A lot of those essential [soil] functions are due to soil organic matter,” adds Claudia. “Depending how we manage soils we can affect those soil ecosystems services.”

The End Game

Ultimately the project aims to explore the practical application of the data collected, such as how farmers can manage their croplands to improve soil health and ecosystem services.

“Our research will quantify the benefits of sustainable soil practices,” explains Claudia. “With a healthier soil, yields are sustainable in the long run, farmers need to use fewer inputs … and we also think the system is more resilient to climate change.”

By providing soil health and crop yield data under different agronomic strategies, Claudia’s research will continue to prove that soil that is much more than dirt and will provide a nod of encouragement to farmers looking to invest in sustainable strategies, helping to feed the world today and into the future.

The Grain Farmers of Ontario, the Ontario Ministry of Agriculture, Food and Rural Affairs and the Ontario Soil and Crop Improvement Associate are providing additional funding for this research project.

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