M.Sc. Defence - Matthew Stewart


Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of Matthew Stewart of the Department of Plant Agriculture

Date: Thursday, September 5th at 9:00am
Time: 9 am
Location: In Room 131, Pestell Student Service Centre, Ridgetown Campus

Available in Guelph via intercom in Room 202, Crop Science Building

Thesis Title: Nitrogen Fertilizer Cover Crop Responses Seeded After Wheat and Effect on Grain Corn Yield

Advisory Committee   
Dr. David Hooker, Advisor 
Dr. Bill Deen, Co-Advisor
Dr. Laura VanEerd
Dr. Manish Raizada

Examination Committee
Dr. Chris Gillard, Chair
Dr. David Hooker
Dr. Laura VanEerd
Dr. Ivan O'Halloran


Cover crops seeded after wheat (Triticum aestivum L.) harvest provide agronomic, environmental and soil health services. End-of-season cover crop populations, C:N ratios and biomass were examined across five cover crop treatments [control, monoculture oat (Avena sativa L.), red clover (Trifolium pretense L.), and 3- and 10-way mixtures], along with two nitrogen treatments (0 and 56 kg N ha-1), and their effect on subsequent corn (Zea mays L.) grain yield in two tillage systems (plow till and “no-till"). There was little evidence to suggest that cover crop mixtures produced more aboveground biomass than monocultures in November, except in Ridgetown in 2018, where monoculture oat was severely infected with crown rust (Puccinia coronata f. sp. Avenae). N fertilizer applied after wheat harvest increased end-of-season biomass of non-legumes and mixtures containing non-legumes (44-93% higher at Elora, 18-21% higher at Ridgetown), and tended to reduce C:N ratios in non-legume cover crops. There was no short-term evidence that grain corn yields were improved by cover crop treatments when corn was adequately fertilized with N, but where no fertilizer N in corn was applied in corn, yields were improved after red clover and decreased after a monoculture oat cover crop seeded after wheat.