Seeding Rate As A Method Of Weed Control In Organic Wheat Production

Roxanne Beavers¹*, Andrew Hammermeister¹, Ralph Martin¹, Brenda Frick², Derek Lynch¹
Organic Agriculture Centre of Canada

See this poster in PDF format

It is common practice for organic farmers to seed grain crops at higher rates than conventional producers. High seeding rates are assumed to provide the crop with a competitive advantage against weeds. An ideal seeding rate for organic systems would balance the competitive ability of spring wheat (Triticum aestivum L.) with maintained yield and quality. The effects of four seeding rates of spring wheat (348, 435, 522 and 695 seeds m-2) at two levels of fertility were assessed in a field experiment at Truro, Nova Scotia over two seasons. Crop and weed biomass production and nitrogen content, yield components, grain quality, and environmental conditions were used to evaluate treatment effects. In both study years, weed biomass was significantly lower at the two highest seeding rates and in low fertility treatments. The effect on individual weed species varied between years. Wheat yield was greatest at the highest seeding rate, primarily due to the increased number of main stems per unit area. Thousand-kernel-weight was not different among seeding rates, although it was negatively impacted by the high fertility treatment. Increased seeding rates appear to be a viable method to reduce weed competition in organic grain crops.

¹ Truro, NS
² Saskatoon, SK
Correspondence: rlbeavers@nsac.ca