Effects of Crop Inputs, Diversity, Environment and Terrain on Yield in an 18-year Study in the Semi-Arid Canadian Prairie


This manuscript was submitted in May 2016 and approved by the acting associate director Susan Tosh. The publication was accepted for publication in February 2017. The citation will be provided, once the publication is posted on the Canadian Journal of Plant Science web page.

Plain language summary

The majority of Canada’s grains and oilseeds are produced in Canadian Prairies. A long-term field experiment was conducted in 1994 - 2013 at Scott, Saskatchewan, Canada. The goal of the experiment was to assess the interaction of cropping diversity and agricultural inputs on crop production in the region. We assessed effects of agricultural inputs and cropping diversity in the context of growing season precipitation, growing degree days/heat units, and field topography on the yield of spring wheat, barley, and canola. This analysis was necessary to show how combinations of different tillage systems, cropping diversities, as well as precipitation, temperature, and topography affect crop yield in the field. Agricultural inputs were organic, minimum, and conventional tillage. Cropping diversities were wheat-fallow, diversified annual grains, and diversified annual perennials. Precipitation in April and June were identified as primary, and inputs, crop diversity, and field topography (slope, elevation) as secondary yield defining factors in this experiment. The analysis also showed that yield was highest in the conventional and minimum, and lower in the organic system. In addition, crop yield was highest in conventional tillage under diversified annual grains and perennials, and in minimum tillage under wheat-fallow rotations, than in any other combination of tillage and diversity. We concluded that precipitation, temperature/heat units and field topography elements were important yield defining factors in this study. These factors should be assessed together when analyzing impacts of tillage systems and cropping diversity on yield, even in a relatively flat landscape.


A field experiment was conducted from 1994 to 2013 at Scott, Saskatchewan, Canada, to assess the effects of cropping diversity and inputs on spring wheat, canola and barley yield in the context of growing season precipitation (GSP), growing degree days (GDD), and terrain attributes. Main-plot treatments consisted of three levels of agricultural inputs [organic (ORG), reduced (RED), and high (HI)] and sub-plots comprised of three levels of cropping diversity [low (LOW), diversified annual grains (DAG), and diversified annual perennial (DAP)]. Yield was highest for the HI and RED, and lower for the ORG system. The HI-DAG, HI-LOW, RED-DAG, RED-LOW rotations produced highest yields. April precipitation was identified as a primary yield driving factor in this study. April precipitation and fixed effects accounted for up to 22 and 10% of yield variation, in analyses by 6-year periods. Terrain attributes explained up to 4.5% of variation in annual yield. The effects of inputs and diversity on crop yield were influenced by GSP, GDD, and terrain attributes, and show the importance of crop management in the context of environmental variability.

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