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Cover Story
Rooted in Resilience: Healthy Soils Support Greener Nurseries and Landscapes
By Dr. Ravi Teja Neelipally, Postdoctoral Research Associate
Dr. Sindhu Jagadamma, Associate Professor, Department of Biosystems Engineering and Soil Science,
with contributions from
Dr. William Klingeman, Professor, Department of Plant Sciences,
University of Tennessee Institute of Agriculture
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Soil was once seen as a lifeless growing medium to anchor roots and to keep plants upright, but our understanding has come a long way. Across the last few decades, we have come to understand soil as a living ecosystem, full of interactions with plants, microorganisms, water, and nutrients that support food production and environmental stewardship. Measuring soil’s performance started with simple ways to quantify tilth, that is, how easy the soil was to work. Later we incorporated chemical analyses to check for pH and nutrient content. While these measurements have been beneficial, they have offered only a limited perspective about soil’s life or health. In the Sustainable Soil Management Laboratory (https://jagadammalab.tennessee.edu/) at the University of Tennessee, our approach reflects a broader perspective in soil science; we are reaching beyond isolated chemical tests and moving towards a more holistic view that integrates biological, physical, and chemical properties of soil. Specifically, we are advancing soil health research by systematically evaluating how soils respond to different management practices across diverse agroecosystems in the region. Some of our work revolves around agroforestry systems, where we conduct deep soil sampling (Fig. 1) to evaluate how perennial crops influence soil carbon storage and overall soil health (Fig. 2). We also pay special emphasis to promote organic grain and forage production by implementing conservation management practices.
Our holistic consideration of soil physical, chemical, and biological aspects is particularly helpful when managing soils in landscaped areas or nurseries, where plant performance and long-term survival are directly impacted by soil health. For example, consider a compacted nursery row where repeated traffic from heavy machinery has reduced soil porosity or a container-grown plant with aging substrate and overhead irrigation cycles that have limited drainage. These conditions restrict water movement and limit oxygen diffusion and root growth. With time, these physical constraints can impair root function, limit nutrient uptake, and reduce plant ability to tolerate drought and establish after transplanting (Fig. 3). Similarly, excessive fertilizer application may disrupt the nutritional equilibrium and soil pH, resulting in a chemical imbalance in soil. For example, when potassium levels become too high, it can interfere with magnesium uptake by the plant. Eventually, this imbalance causes chlorosis, reduces photosynthesis, and makes plants more vulnerable to abiotic and biotic stressors. These imbalances may go unnoticed at first but can gradually weaken plant health in both landscape and nursery settings. Likewise, when soils lack sufficient organic inputs, microbial activity declines, limiting mineralization of organic nutrients in the soil and weakening the soil’s biological support system. Across time, these outcomes can reduce beneficial microbial populations and their root exudate formations, thus increasing plant vulnerability to diseases, especially in landscape installations and container-grown plants that are transplanted into field soils. Excitingly, enhancing soil organic matter (SOM) is one strategy that can help address challenges that diminished soil and substrate conditions may impose. Increased SOM content enhances soil structure, regulates nutrient levels, and boosts beneficial microorganisms.
Role of Soil Organic Matter (SOM)
Soil organic matter is more than decomposed plant residues. SOM includes live microbial biomass and organic residues of varying stages of decomposition that drive soil function. In nursery, ornamental, and landscape systems, SOM plays a vital role in buffering against soil compaction, nutrient loss, and biodiversity decline. SOM also builds microbial communities, enhances nutrient availability, and supports better moisture management (Stukenholtz, 2021). These functions make SOM a foundation for resilient soils, setting the stage for practical management approaches that follow.
Building SOM in Practice
Harvesting balled-and-burlapped nursery stock with 44-inch root balls can remove as much as 470 tons of soil per acre across a five-year production cycle (UMass Extension, 2014). Harvesting these trees removes both soil volume and the organic-rich top layer, making it essential to rebuild SOM to restore soil health in nursery and landscape systems. In field nurseries that grow ornamentals in rows, SOM can be increased by incorporating organic amendments such as manure and composted pine bark (Fig. 4) into planting zones. If time and resources are available, growing cover crops like cereal rye, sudex, and other grass species adds organic matter to the soil and preserves soil structure between seasons, while permanent groundcovers like tall fescue between rows reduces erosion and allows machinery access even during moderately wet periods.
In containerized nurseries where pine bark-based mixes are widely used, SOM management helps in maintaining a healthy growing medium. These organic substrates gradually break down and can lose structure and nutrients over time, especially under frequent irrigation.
To counter this, growers can add stabilized compost or vermicompost to refresh the media, support microbial activity, and enhance nutrient retention. Some nurseries also apply microbial inoculants during production or transplanting to strengthen the root-microbe relationship and improve plant establishment in the field (Pascual et al., 2018).
Carbon Inputs and Lasting Benefits
Because almost half of SOM is composed of carbon, increasing SOM also means increasing soil carbon. Organic amendments like pine bark and composted mulch are slow to break down, helping to build long-term soil health (Fig. 4). Research by Prior et al. (2011) showed that planting container-grown ornamentals using pine barkbased media increased carbon levels in the topsoil from about 2% to between 9 and 25%. That is a significant improvement, and for professionals in the nursery and landscape industry, this presents an opportunity to improve soil structure, boost biological activity, and enhance carbon storage by choosing the right planting substrates, amendments, and practices.
Microbes at Work
Microbes are indispensable contributors to soil health. Microbial activity drives nutrient cycling, decomposes organic matter, and facilitates better root-soil interactions. By unlocking nutrients that are already present in the soil, microbial communities help reduce dependence on synthetic fertilizers while supporting efficient nutrient uptake and plant growth. These biological benefits are particularly valuable in low-input ornamental beds and turfgrasses, where mycorrhizal fungi and microbial inoculants are increasingly used to improve plant vigor without the need for frequent fertilization.
In nursery production, practices such as applying compost, manure (Fig. 5), or growing cover crops help cultivate beneficial microbial populations. Beyond nutrition, microbes also help defend plants from disease by activating natural resistance pathways. Soils enriched with compost or treated with microbial teas have shown reduced disease pressure from common fungal diseases like damping-off and powdery mildew (Gaskin et al., 2013). Encouraging microbial life through organic matter inputs and reduced pesticide use ultimately leads to more resilient nursery and landscape systems.
Key Takeaway Actions for Landscape Professionals
Refresh bark-based container mixes with stabilized compost or vermicompost to maintain structure and microbial life.
Use microbial inoculants at transplanting to enhance root-soil interactions.
Maintain vegetated alleys (e.g., tall fescue) between nursery rows to reduce erosion and improve traffic tolerance.
Choose mulch or compost based on traffic and slope conditions to minimize runoff and temperature extremes.
Improving soil health not only benefits plant growth, soil-health building actions taken also support the long-term value of landscape and nursery systems. As interest in carbon sequestration grows, nursery and landscape professionals have growing opportunity to position their work as part of green solutions. Using and promoting soil-friendly practices can add value to the plants grown and align with the growing demand for more resilient landscapes.
Referenced Resources and Additional Reading
Stukenholtz, L. (2021). Advanced soil organic matter management. Michigan State University Extension. https://www.canr.msu.edu/resources/advanced_soil_organic_matter_management [Retrieved July 27, 2025]
UMass Extension: https://www.umass.edu/agriculture-food-environment/landscape/best-management-practices-bmps-for-nursery-crops/soil-conservation [Retrieved July 27, 2025]
Pascual, J. A., Ceglie, F., Tuzel, Y., Koller, M., Koren, A., Hitchings, R., & Tittarelli, F. (2018). Organic substrate for transplant production in organic nurseries. A review. Agronomy for Sustainable Development, 38(3), 35.
Prior, S. A., Runion, G. B., Torbert, H. A., Gilliam, C. H., & Marble, S. C. (2011). Strategies for carbon sequestration and reducing greenhouse gas emissions from nursery production systems. USDA-ARS & Auburn University Technical Report, 55.
Gaskin, J. W., Hartel, P., Little, E., & Harris, G. (2013). Soil inoculants (Circular 990). University of Georgia Cooperative Extension https://secure.caes.uga.edu/extension/publications/files/pdf/C%20990_2.PDF [Retrieved July 27, 2025]
UT Sustainable Soil Management Laboratory, Biosystems Engineering and Soil Sciences: https://jagadammalab.tennessee.edu/
UT Extension, Commercial Horticulture: https://utextensionanr.tennessee.edu/commercial-horticulture-2/
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This article showcases information presented at the Tennessee Green Industry Field Day about strategies to enhance soil health and landscape sustainability. Photos and field examples courtesy of the UT Sustainable Soil Management Lab.
