Using a 4Rs Plus approach to improve growth and sustainability of annual cropping systems in Saskatchewan

Term: 4 years, ending March 2026
Status: Ongoing
Researcher(s): Blake Weiseth, Discovery Farm; Jeff Schoenau, University of Saskatchewan; Etienne Shupena-Soulodre and Doug Johnson, Watershed Authority
SaskCanola Investment: $108,100
Total Project Cost: $188,000
Funding Partners: Sask Wheat

Project Description

4R Nutrient Stewardship is a tremendous success story of a decision support framework that has been widely adopted among Canadian Prairie farmers as an easily understood tool to optimize agricultural productivity through judicious fertilizer use and subsequently manage risk. However, despite the justifiable emphasis that has been placed on 4R Nutrient Stewardship, producers face significant risk related to managing water in the landscape as evidenced by the period of abnormally wet years from 2010-2014 which saw millions of acres of cropland impacted by flooding in Saskatchewan. On the other hand, risk of crop failure due to sub-optimal moisture conditions is also a relevant concern for many growers in the semi-arid climate of Saskatchewan. Significant uncertainty persists as to the impact that agricultural management practices may have on optimizing water use efficiency and the fate of applied fertilizer in run-off water. While it seems intuitive to conclude that the same practices suggested by 4R Nutrient Stewardship including sub-surface nutrient application at seeding and minimal tillage used to manage crop residue would lead to optimal water use efficiency, little field research has been conducted to support these claims. If validated through field research, the 4R Stewardship framework could easily be adapted to a “4Rs Plus” framework that includes a consideration of the impact that optimal water use efficiency has on influencing agronomic performance and limiting off-site losses of applied fertilizer in runoff water.

Purpose

The BMPs under investigation in the current project have been rationalized within a context of 4R Nutrient Stewardship and are typically designed based on their proved ability to limit gaseous and leaching losses of N within the landscape. However, the ability of these BMPs to influence the run-off water volume and N and P losses in spring snowmelt surface run-off water remains largely unexplored. For example, variable rate fertilizer application which accounts for residual soil nutrients and anticipated crop demand based on estimated soil productivity potential will presumably result in reduced nutrient losses in run-off water compared to a fixed fertilizer application rate. The project proposed herein seeks to extend the length of a two-year field study currently underway at Discovery Farm Langham to provide additional site-years of data to validate the efficacy of the evaluated practices.

Goal

To conduct a field scale evaluation of BMPs under locally relevant soil and climatic conditions including a cost-benefit analysis of BMPs. This project also seeks to evaluate the impact of micro-variation in topography on nutrient transport mechanisms across the landscape.

Objectives

  1. Assess the impact of 4R Nutrient Stewardship practices on influencing N and P crop uptake and load in run-off water.

  2. Assess the impact that variation in topography across landscape has on influencing N and P load in run-off water.

  3. Conduct in-situ assessment of run-off water volume and nutrient characteristics as influenced by management practices evaluated.

  4. Cost-benefit analysis of 4R and associated practices for production benefit and economic efficiency to reduce nutrient run-off.

Other References to this Research Project

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Functional validation of Brassica napus genes related to clubroot resistance through high-throughput CRISPR/Cas9 genome editing

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Discovering the optimal rate of a dual-inhibitor N-fertilizer for maximum N2O emissions reduction