Many of the most pressing environmental issues require effective soil management to resolve them: climate change; global food shortages; lack of quality drinking water; and human health (toxicology).
Adaptation and land modelling
Under our changing climate, there is great need for improved understanding of how ecosystems are responding to change and how our land use and management practices can be adapted to maximize ecosystem function while still meeting society’s demands for renewable resources. Research activities in this area include improving our digital data repositories of landscape-scale soil and vegetation information through the use of novel techniques such as remote and proximal sensing (including via UAV) and digital soil mapping. This improved digital data is then used to inform modelling efforts focused on climate change response and adaptation.
Soil organic matter (SOM) is critical for several key ecosystem services and is commonly used as an indicator of soil quality. SOM is also the greatest terrestrial sink of carbon, but this pool is very sensitive to land management practices. Research in the area of soil organic matter accumulation, composition, protection, and mineralization is essential in our understanding of the global carbon balance, including carbon sequestration and greenhouse gas emissions. This research informs policy and practices related to land management and climate change.
Dendrochronology is the science of using tree rings to study past environmental indicators of our changing landscapes. Trees have the ability to incorporate their growing environment into each annual ring and therefore are a storage vessel of past conditions. Conditions such as past soil chemistry, past temperature and moisture conditions, and past ecosystem health are all possible to study from simply reading the rings of trees which have been monitoring their growing environment in a specific location, for at times, hundreds of years.
Agriculture is responsible for approximately 10 % of Canada’s greenhouse gas emissions, excluding emissions from the use of fossil fuels and fertilizer production. In cropped systems, nitrous oxide and carbon dioxide are the major greenhouse gases emitted, although soils can be net sources or sinks for carbon dioxide depending on a variety of factors. Research on greenhouse gases focuses on two main areas: innovative measurement of greenhouse gas emissions and identifying management practices that reduce the overall greenhouse gas footprint of different production systems. The goals of this research area are to provide reliable emission estimates for the Canadian Greenhouse Gas Inventory from Canadian prairie systems, and to support sustainable food production that minimizes greenhouse gas emissions per unit of food product produced.
Agroforestry is the incorporation of trees into the agricultural landscape and include shelterbelts, tree plantations and biomass energy plantations in the province. We have been studying the agronomy of growing hybrid poplar and willows trees on farm land, modelling potential yields, and investigating how these systems can be used to mitigate greenhouse gases by increasing carbon sequestration in soils and biomass as well as affecting greenhouse gas fluxes.
Behaviour and fate of soil active herbicides
An increasing number of herbicides have phytotoxic properties related to their interaction with the soil. The impact of soil properties on the activity, efficacy and persistence of various herbicides in prairie soils is investigated via novel bioassay techniques. The bioassays are also developed as a tool for screening weeds for resistance to various herbicides.
Processing of agricultural products frequently produces byproducts with physical and/or chemical properties that could benefit other areas of agriculture. For example, distiller's grains and thin stillage are byproducts of ethanol production with potential as nutrient amendments when land applied. Likewise, biochars have potential to enhance carbon sequestration, improve water storage and nutrient supply. Research on microbial bioproducts focuses on evaluating and developing microbial inoculants and inoculant carriers for improving plant nutrient acquisition. Research on bioproducts aims to add value to agricultural systems.
The management of agroecosystems systems is challenging because they are constantly changing; moreover, there is increasing concern regarding the potential negative environmental impacts of conventional agriculture. Cropping systems research at the University of Saskatchewan seeks to establish agronomic practices that enhance nutrient use efficiency to achieve optimal yields while also minimizing the environmental footprint of the cropping system. The overall goal of this research is to enhance agroecosystem sustainability in the context of a changing climate and increasing global population. Cropping systems research is interdisciplinary and integrates across spatial and temporal scales—from micro-scale processes occurring in the rhizosphere to macro-scale processes operating at the landscape—and watershed-scale.
Fertilizer management and use
Fertilizers often represent the largest single input expenditure to grow crops profitably and sustainably. The 4R fertilization principles of right source, right rate, right timing and right placement help growers achieve maximum crop benefit while at the same time minimizing the loss of nutrients to air and water. Research is conducted to add to our knowledge base for 4R practices that increase plant nutrient use efficiency and the associated agronomic, economic and environmental gains from the inorganic and organic fertilizers we add to our soils.
Losses of nutrient from the soil are of environmental concern as they can contribute to greenhouse gas load in the air, and to the deterioration of quality of surface and sub-surface water sources. The effects of soil management practices including nutrient additions, crop type and rotation, tillage practices on soil nutrient losses in gaseous form and in run-off water are evaluated in field and controlled environment research work.
Soil ecology and microbiology
Soil microbiology is the study of the microscopic organisms (bacteria, archaea and fungi) that live belowground. Soil ecology examines the various roles of micro-, meso- and macro-organisms, their interactions with each other and with their environment. Research focuses on identifying how natural environmental variation and soil management affect the biota that perform fundamental ecosystem functions including increased plant growth and stress resistance, regulation of biogeochemical cycles and nutrient availability and breakdown of contaminants. This includes the exploitation of microorganisms that can be used as inoculants, sources of nutraceuticals, or as biological controls against disease causing pathogens. Research aims to enhance the role of soil biota in food and fibre production for profitable and sustainable agricultural systems.Sina Adl
Understanding how contaminants move, interact and influence plant-soil systems is essential for providing solutions for industry-driven challenges. Determining the toxicity of hydrocarbons, heavy metals and herbicides in site-specific soils and plants can be used to assess the risk these contaminants may pose within a given ecosystem. Research on contaminant movement and partitioning can inform innovative solutions to restore terrestrial environments and ensure long-term ecosystem health.
Reclamation, Remediation and Restoration
Anthropogenic activities, including mining, oil and gas exploration, transportation, utility and community infrastructure, can result in the release of contaminants and cause physical disturbance of natural ecosystems. Promoting ecosystem health in these disturbed plant-soil systems relies upon our ability to identify the key ecosystem functions that must be restored. Research focused on identification of suitable soil amendments, native plant species and site-appropriate techniques can assist in creating sustainable nutrient cycling pathways that ensure long-term recovery.
Biogeochemical cycling encompasses the biological, geological, chemical, and physical processes that transform and move energy and elements through Earth’s systems. Soil biogeochemists study how critical elements such as carbon, nitrogen, and phosphorus are cycled in order to understand important ecosystem functions such as the supply of nutrients to plants, the production and mitigation of greenhouse gas emissions, contaminant remediation, and carbon sequestration in the soil. Research is focused on multiple spatial scales, from within the plant rhizosphere to across landscapes, as well as on understanding and predicting the effects of climate and land use change on biogeochemical cycling in managed and natural ecosystems.
Soil biota comprise a huge proportion of the biodiversity on earth. They are responsible for a myriad of essential ecosystem services including decomposition of organic matter and pollutants, plant growth control, pathogen suppression and biogeochemical cycling of nutrients that impact carbon storage, gas exchange and water quality. Diverse soil microbial communities are better able to withstand changes that occur in their environment, leading to increased functional resilience in the face of negative impacts of human activity or climate change. Research focuses on characterizing the identity and function of soil biota and aims to maintain or enhance the diversity of belowground communities.
Water is essential ingredient of any natural and managed ecosystem, but is also the carrier of pollutants, which affect the environment adversely and make pollution nonlocal. Soil hydrology aims to understand and, through management, to optimize soil’s ability to store and release water and how plants to utilize soil water. For example, understanding of crops’ preference to deep soil water or shallow soil water helps farmers design drought-resilient rotations. Research found that water regime of uniform sandy soil favors a Jack pine forest, while that of layered soil supports a mixed forest. This understanding guides reclamation industries to reconstruct soil that favors a target vegetation cover. Soil hydrology, as the study of soil physical, hydraulic and thermal properties and processes in soil and their coupling with vegetation, improves agricultural and natural ecosystem productivity, health and sustainability.
Soil organic matter
Soil is a living, functioning entity, and soil organic matter provides the energy and nutrients to fuel and sustain the biological activity and functions of soil. Soil organic matter describes a variety of organic materials including plant and animal materials in various stages of decay, together with a vast array of organic materials of microbial origin. Together, these materials contribute to the structural integrity of the soil, thereby modifying physical processes, and through microbial decomposition, further release inorganic constituents that ultimately support plant growth and ecosystem health. Despite the importance of soil organic matter, questions remain regarding the mechanisms that stabilize and protect this essential component of soil, and researchers in the College of Agriculture and Bioresources are using cutting edge techniques, such as microbial molecular analyses and synchrotron-based approaches to shed light on the mechanisms by which soil organic matter is protected and stabilized in agroecosystems.
The Department of Soil Science is an international leader in field-based, landscape-scale research and faculty are actively involved in research that focuses on terrestrial and aquatic ecosystem health—linking basic micro-scale science (involving synchrotron-based, molecular-scale studies to elucidate fundamental processes at work) to real world issues at the landscape (studying the interaction of soil, topographic, and environmental factors to better understand ecosystem functioning) and global (investigating climate change impacts on prairie and arctic ecosystems) scales. The Soil Science graduate program provides core expertise in soil and environmental sciences and offers opportunities for advanced study and research leading to M.Sc. and Ph.D. degrees.
Areas of research strength include applied pedology, nutrient cycling and management, environmental soil science, soil remediation and reclamation, soil biology, soil chemistry, soil fertility, soil physics and hydrology, soil-plant interactions.