Crop sequencing effects of seven crops on grain yield, volunteers, and weeds in Saskatchewan

Abstract

Every growing season, producers must decide which crops to grow and in what sequence to enhance returns and sustain productivity. However, when producers consider growing specialty crops like canary seed (Phalaris canariensis L.), coriander (Coriandrum sativum L.), hemp (Cannabis sativa L.), or quinoa (Chenopodium quinoa Willd.), data are lacking to assist with their assessments. This study evaluated the integration of these crops into prairie rotations through a 5-year, multi-location field experiment (2015–2019) across 13 site-years at Indian Head, Melfort, Saskatoon, and Swift Current. The experimental design was a split-block with crop stubble as the main plot and crop as the subplot. Most sites experienced below-average precipitation with near-normal temperatures, providing insight into water-limited conditions. Stubble only affected plant density in wheat (Triticum aestivum L.) and coriander. Both coriander and canola (Brassica napus L.) stubble had an elevated level of volunteers in the subsequent crop that needs to be controlled. Weed biomass was impacted by stubble type in field pea (Pisum sativum L.), canary seed, hemp, and coriander, but not in wheat, oat (Avena sativa L.), canola, or quinoa. Oat stubble tended to have among the lowest weed biomass of any stubble. Crop biomass production increased when crops followed field pea, reflecting legume rotational benefits. Grain yield of oat, canola, pea, and coriander was affected by crop stubble. Oat and canary seed stubble reduced oat grain yield. Pea stubble improved canola yield, while cereal stubble was beneficial for pea and coriander. Pea stubble also increased grain protein in wheat and canola. These results underscore the importance of crop sequencing on weed management and grain yield in a semi-arid cropping system.