b'More and more growers are incorporating them into their rotations, so were trying to see if theres an additional effect on the weed seed bank.McKenzie-Gopsill notes some research has beenLambs quarters is a prolific seed producer.conducted into the use of brown mustard as a biofumi- Were trying to see if we can suppress it with our gant against weed seeds. He adds buckwheat is known as a good weed suppressor but its unclear whether itcover crops as well as to see if theres any effect has a biofumigant effect on the weed seed bank.on that weed seed bank with these coverTimothy was included because its often growncrops and then various termination methodsin a potato rotation as a forage crop, while the hairy vetch, crimson clover and annual rye mix ison top of that. something thats being incorporated more and more ANDREW MCKENZIE-GOPSILLinto AAFC studies, McKenzie-Gopsill says. The three-year research project, which wraps up this year, is being conducted at the AAFCs Research and Development Centres in Prince Edward Island and New Brunswick and involves numerous collabo- From what Im seeing and some of the databiomass or mulch thats left once each cover crop is rators in both provinces. were collecting, it produces a ton of biomass andterminated by the following four means:McKenzie-Gopsill says the study started withreally kind of chokes everything else out, says applying glyphosate research plots being planted with the cover cropsMcKenzie-Gopsill.mowingin 2018 and then planted with potatoes in 2019 toHe notes there was also a reduction in weed pres-mowing and diskingmeasure the effects of each cover crop on the weedsure with buckwheat, while timothy was less effective using a roller crimperseed bank. The process is being repeated on anotherat suppressing weeds than the other cover crops. When theres lots of mulch left over in the field, set of research plots where potatoes will be plantedWe had a pretty hard time getting the timothythis creates a favourable environment for weed seed this year.to establish, McKenzie-Gopsill says. The field thatpredators such as soil-dwelling invertebrates, small McKenzie-Gopsill says the research datahad timothy really looked more like a field of lambsmammals and birds, McKenzie-Gopsill notes. If continues to be assessed and that a full report onquarters than anything else. conditions are right, he says, up to 40 per cent of a the study will be released in 2021. He did offer up afields weed seeds can be eliminated in this way. few general observations from the first year of theIMPORTANCE OF MULCH McKenzie-Gopsill says clear differences in the study, however. Another important aspect of the study is how differ- amount of biomass produced by each termination The hairy vetch, crimson clover and annual ryeent methods for terminating cover crops will affectmethod have been observedand the roller crimper mix, for example, appeared to be quite effective as athe weed seed bank.treatment in particular resulted in a fantastic layer weed suppressor.The researchers are measuring the amount ofof mulch.Research plot containing a cover crop mix of hairy vetch, crimson clover and annual rye in season. PHOTO: AAFCWINTER 2020 SPUDSMART.COM 35'