The effect of input intensity, cropping rotation, environmental and terrain covariates on crop yield in a 19-year study in Saskatchewan Canada

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Résumé

The long-term Alternative Cropping System field experiment was conducted in 1994 – 2013 at Scott, SK to assess the role of input and diversity in sustaining crop production and soil quality in the Canadian Prairies. This research investigated effects of input, diversity, growing season precipitation (GSP), growing degree days (GDD), and terrain attributes (planar and profile curvature, wetness index, and percent slope) on the yield of spring wheat, barley, and canola. The experiment was a four replicate split-plot with main plot treatments consisting of three levels of 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)]. Data were analyzed with the MIXED model procedure, partial least squares analysis, partition analysis, analysis of variance and covariance. Results indicated that input and diversity affected crop yield. Yield was highest in the HI and RED systems, while ORG system had lowest yield due to nitrogen deficiency and in part due to weed competition. Crops grown in the HI-DAG, HI-LOW and RED-DAG, RED-LOW rotations produced higher yields compared to all other combinations of input and diversity. Both GSP and GDD had significant impact on crop yield, with April, June, July GSP and July GDD having the most impact followed by the effects of input and diversity, depending on the crop. The effect of terrain attributes was especially evident in years with deficit or excess moisture, which explained 8 to 45 percent of variation in wheat yield. Terrain attributes, GSP, and GDD should be assessed when analyzing impacts of fixed effects like input and diversity on crop yield to account for variability due to weather, micro-topography or landforms.

Date de publication

2015-06-16

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