Naresh Thevathasan

Head shot of Naresh
Adjunct Professor (Retired Associate Professor)
Phone number: 
(519) 824-4120, Ext. 52565
Alexander Hall, Room 121
Bovey Building

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Naresh grew up in the South Asian country of Sri Lanka. He comes from an agricultural background and developed an interest in tree-based inter-cropping systems after the Sri Lankan government began moving toward diversification of agricultural systems. This is how Naresh developed his interest in agronomy and agroforestry. Naresh’s research mainly focuses on carbon sequestration and nutrient cycling dynamics in temperate agroforestry systems and purpose-grown biomass crops research and development. 

Academic History 

  • B.Sc. Agronomy- Tropical Agriculture, Eastern University, Sri Lanka (1987)
  • Ph.D. Agroforestry, University of Guelph (1998)

Affiliations and Partnerships 

  • Kwame Nkrumah University of Science and Technology (KNUST) - Ghana
  • Ontario Ministry of Agriculture, Food and Rural Affairs
  • Agriculture and Agri-Food Canada 
  • Environment and Climate Change Canada
  • Ontario Soil and Crop Improvement Association
  • Grand River Conservation Authority
  • Natural Resources Canada
  • Awards and Honours 
  • Doctor of Science Honourary Degree, Kwame Nkrumah University of Science and Technology, Ghana (2011)

Research Impact 

In tropical semi-arid areas rainfall is low, and land holdings are small, trees can change the micro climate and reduce water loss while making water available for associated agricultural crops. This also leads to increased revenue for the land owners by providing them revenue from the agricultural products and the trees. An example of this was a collaborative project with KNUST, Ghana, where Prof. Andy Gordon and Naresh designed agroforestry land use systems in Ghana to enhance food production in a sustainable and climate resilient manner. The project brought 845 households out of poverty. 

Current projects include enhancing terrestrial carbon sequestration by biomass crops and the sustainability aspects related to soil carbon, and enhancing riparian buffer plantings around degraded agricultural streams within respected watershed areas. Another aspect of his research looks at greenhouse gas emissions associated with biomass crops in agroforestry systems.  

Current Research Projects 

Soil carbon sequestration in woody and herbaceous bioenergy crop production systems on marginal lands in Ontario 

About 50 to 100 GT of soil carbon is released into the atmosphere as a result of land-use change and land-use management practices since the industrial revolution. Potentially this lost soil carbon can be sequestered by increasing organic matter in soil. Soil organic carbon (SOC) build-up is a slow process and a good understanding of SOC dynamics requires long-term investigations. This project will quantify long-term SOC build up since 2009 as influenced by woody and herbaceous biomass crops, and is funded by OMECC and the Best IN Science Program.

Agroforestry land-use for greenhouse gas mitigation and the benefit of Canadian agriculture 

The influence of the perennial component (trees), age class, the soil type in relation to carbon sequestration and the reduction of greenhouse gas emissions, in the terrestrial and aquatic component of Riparian buffer systems are not well understood. This study will adopt a research network-approach with multiple partners and locations to address the lack of science, technology and mechanisms currently available. It will correlate the multiple ecosystem service provisioning in RBS with GHG emission reduction potentials in the terrestrial and aquatic component of RBS. This project is funded by Agriculture and AgriFood Canada through the Agricultural Greenhouse Gases Program (AGGP). 

Measuring soil organic carbon in Ontario biomass crops 

Ontario biomass crop acreage is on the rise. These lands with sound management practices could potentially increase soil carbon sequestration, enhance soil health, water quality and support ecosystem services. This study will quantitatively measure soil carbon sequestration values for biomass crops grown in different soil types and apply these values to predict future Soil Organic Carbon (SOC) sequestration. A GIS database and maps with baseline SOC values will be developed. This project is funded by the OMAFRA-U of Guelph Agreement and is also highly supported by the following external partners: Ontario Biomass Producer Cooperative Inc., BioFuelNet Canada, Canadian Wood Fibre Centre, NRCan. 

Assessment for Soil Health, Carbon Sequestration and Nutrient dynamics in Perennial Biomass Crops (switchgrass, miscanthus) On-Farm Production System 

Perennial biomass crops, such as switchgrass and miscanthus hold significant economic and environmental promise for Ontario. The objective of this study is to investigate soil health assessment and changes in soil organic matter and carbon sequestration potential of these biomass crops established six to ten years ago in different soil types in South Western Ontario. Soil carbon sequestration potential and soil health indicator metrics in different soil zone depths will be assessed. This project is funded by the OMAFRA Best Management Practices Verification and Demonstration Fund. 

To learn more, read Naresh' researcher information sheet.

Graduate Student Information 

Naresh is retired and doesn't accept any new graduate students. 

Featured publications 

  • Muhammad Waseem Ashiq, Amir Behzad Bazrgar, Houman Fei, Brent Coleman, Kevin Vessey, Andrew Gordon, Derek Sidders, Tim Keddy and Naresh Thevathasan (corresponding author) (2018).  A nutrient-based sustainability assessment of purpose-grown poplar and switchgrass biomass production systems established on marginal lands in Canada. Can. J. Plant Sci. 98: 1–12.
  •  Marsal F., Naresh V. Thevathasan*, S. Guillot,  A. M. Gordon, M. Thimmanagari, W. Deen, S. Silim, R. Soolanayakanahally and D Sidders (2016). Biomass yield assessment of five potential energy crops grown in southern Ontario, Canada. Agroforestry Systems. DOI 10.1007/s10457-016-9893-3 (*corresponding author)
  • Wotherspoon, A., Naresh V. Thevathasan, Andrew M. Gordon and R. Paul Voroney (2014). Carbon sequestration potential of five tree species in a 25-year-old temperate tree-based intercropping system in southern Ontario, Canada. Agroforestry Systems: DOI 10.1007/s10457-014-9719-0
  • Thevathasan, N. V. and A.M. Gordon (2004). Ecology of tree intercropping systems North temperate region: Experiences from southern Ontario, Canada. Agroforestry Systems 61: 257-268.
  • Thevathasan, N. V, Brent Coleman, Lisa Zabek, Tricia Ward and Andrew Gordon (2018). Agroforestry in Canada and its role in farming systems. In: Andrew M. Gordon, Steven M. Newman and Brent R.W. Coleman (eds.), Temperate Agroforestry Systems (2nd Edition). CABI International, 313 pp.

For a full list of Naresh’s publications, please visit his Research Gate page.

Area of Research

Plant and Environmental Health