NWT RESEARCH DATABASE

Regions: Dehcho Region, South Slave Region

Tags: agriculture, soil sampling, soil fertility

Objective(s): 1) to improve our understanding of local-scale soil fertility variation in southern NWT by continuing the long-term Northern Agricultural Futures program. 2) to understand the effects of both wildfire and short-term cultivation on nutrient retention in these soils.

Project Description: This licence has been issued for the scientific research application No. 5968. The objective of this project are: 1) to improve the understanding of local-scale soil fertility variation in southern NWT by continuing the long-term Northern Agricultural Futures program. 2) to understand the effects of both wildfire and short-term cultivation on nutrient retention in these soils. The intent is to provide local decision-makers with information on where to grow food locally. Regional Fertility Study: To understand drivers of soil fertility in the study area, a team will visit approximately 50 study sites that varying in (i) ecosystem type (ii) drainage conditions (iii) vegetation community structure (iv) expected soil type and parent materials, and (v) wildfire history. The study sites will be selected following community consultation to ensure the target locations are highly pertinent to local interests, accessible, and protect culturally significant areas. At each of the sites, a 30-meter transect will be set up in the North-South direction. At the 0, 15, and 30-meter marks along the transect, surface soil cores will be taken to a depth of 30 centimeters. Each soil core will then be transported to the University of Guelph, in Ontario and tested for total carbon, nitrogen, potassium, and phosphorus as well as ammonium, nitrate, phosphate, soil pH, cation exchange capacity and organic matter content. In addition to soil cores, the team will also characterize the surface and overstory vegetation community structure of each site. Using statistical methods the team will be able to determine factors that influence soil nutrient content in southern NWT and help local growers identify indicators of fertile soil around their communities. Soil Sustainability Study: To test the ability of different soils to retain nutrients after being used to grow food, a mesocosm style experiment will be conducted using a subset of cores collected in the regional fertility study. Specifically, the experiment will identify low, mid, and high fertility soils from both recently burned (wildfire event in 2023) and historically burned (last wildfire event prior to 1980) sites. These soils will be kept separate by soil fertility class and wildfire history and placed into 5-gallon buckets and planted with potatoes and strawberries — crops of interest to community partners in southern NWT. Every two weeks, porewater will be collected from the buckets to assess changes in available dissolved nutrients throughout the growing season. At the end of the summer soils from the buckets and the plant material itself will be collected and sent back to the University of Guelph for nutrient testing (specific nutrients listed above). Using statistical analyses, it will be determined which northern soils produced the most potatoes and which soils retained the most nutrients throughout the summer. While staying at the Aurora Research Institute, MSc. candidate Jane Mariotti and field technicians will participate in local grower's events hosted by Aurora College. This will be an opportunity to present the research, receive feedback, and collect input from community members on sampling locations. The team will also participate in workshops on local food production hosted by members of Dr. Andrew Spring's lab group in the communities of Kakisa and Fort Smith. These workshops will serve as knowledge sharing opportunities. To facilitate effective two-way knowledge sharing the research team will employ at least one community member from a partner community. This will help ensure the research remains centered on community concerns and will generate new products that have direct application for end users. In the Summer 2025 field season, Jane Mariotti plans to return to NWT and report preliminary findings with communities during grower's events and workshops. At the end of Jane's MSc. program, all results will be translated into accessible formats and shared with the communities of Kakisa, Hay River, and Fort Smith. The fieldwork for this study will be conducted from: August 9 - December 31, 2024