February 15, 2010
By Jen Llewellyn
OMAFRA nursery crops specialist

Biochar and agriculture

About a year ago, I was talking to a nursery grower, who brought up the topic of biochar. It is essentially charcoal that is the by-product of heating plant-based fuels (e.g. wood, corn stalks, etc.), or biomass. The term is commonly found on the Internet. Biochar is produced through a process known as pyrolysis. During this process, combustible gases are produced and these can be harvested as a source of fuel known as biogas.

Biomass, biogas and bio-oil units are becoming increasingly popular alternative fuels in Ontario agriculture. Biochar is essentially a waste product from this process. It is largely made up of carbon and is very stable. Biochar may also have potential as part of a solution to mitigate rising levels of carbon dioxide, as a form of carbon sequestration. Ultimately, plants are the solution as they remove carbon dioxide from the atmosphere in order to make their own energy. Biochar may be a means of locking up some of that biomass carbon for long term storage.   

One hot topic

Biochar is also reputed as a novel soil amendment in North America. Right now, it is one hot topic. The idea (terra preta) comes from tropical regions, such as those in the Amazon, where farmers have used charcoal to improve soil tilth and crop yields for thousands of years. If you search for information on “biochar and agriculture” or “terra preta” on the Internet, you will find some striking photos of the positive benefits to tropical soils, most notably on poor soils. Recent studies indicate that biochar has more potential as a soil amendment on tropical soils with low organic matter and low nutrient holding capacity. Research demonstrating its effect on our temperate soils is underway.

Scientists in North America have been assessing the ability of biochar to improve nutrient holding capacity (Cation Exchange Capacity) and to stimulate soil microbiological activity. Results are slowly trickling in from the assessment. In the meantime, we thought it would be interesting to incorporate char into soilless container media to determine if it had any impact on nutrient holding capacity of media in nursery production. The original idea came from Ted Spearing of Ground Covers Unlimited. We have been working together on a demonstration trial at his nursery on container-grown trees this summer. Fertilizer prices have nearly doubled in the last couple of years, as have plastics, fuels and several other inputs into crop production. Our goal was to determine whether the addition of char could be used to reduce fertilizer application rates. What if we could reduce fertilizer inputs by 50 per cent? We analyzed the results and presented them at the LO Nursery Growers Short Course at the RBG in Burlington on.  

Specialists work for you

Each fall, representatives from the nursery and landscape sectors come together to talk with OMAFRA specialists about research and pest management needs for outdoor ornamentals. Outdoor ornamentals is the term used by the Pest Management Regulatory Agency and the Pest Management Centre to describe nursery crops and landscape plants. It is my responsibility to report these priorities to our Provincial Minor Use Coordinator, who assembles them and submits the report to the Agriculture Agri-Food Centre’s Pest Management Centre in Ottawa.

Thankfully, here in Canada, we have the Pest Management Centre and the Minor Use System to help obtain label expansions for crops such as outdoor ornamentals.  Every March, provincial specialists, industry representatives and registrants meet and jockey for the top 10 positions of minor use priorities that will be addressed through efficacy trials the following year. And as you can see by the products listed below, we have been very successful at increasing the toolkit for the nursery and landscape industries through this system. That is important for an industry in which commodities and pest problems are so diverse, that they are often overlooked by registrants because of extra data requirements and the level of potential sales. One of the other strategies we employ that helps increase our success with the minor use system is cross-provincial consultation.

The following is a summary of awarded Minor Use Registrations and current Minor Use Projects in the system, compiled by Jim Chaput, OMAFRA Provincial Minor Use Coordinator. URMULE is the acronym for User Requested Minor Use Label Expansion.

URMULE registrations 2009 – outdoor ornamentals

  • Subdue Maxx (metalaxyl-m) – sudden oak death on greenhouse and outdoor ornamentals
  • Acrobat (dimethomorph) – sudden oak death, downy mildew on outdoor ornamentals
  • Rhapsody (Bacillus subtilis) – disease suppression on greenhouse and outdoor ornamentals
  • Orthene (acephate) – injection method for insects on selected conifers

Other registrations

  • MET 52 (Metarhizium anisooliae) – black vine weevil, strawberry weevil on outdoor and GH container ornamentals
  • Sureguard (flumioxazin) – weeds on field grown outdoor ornamentals
  • Broadstar (flumioxazin) – weeds on container grown woody outdoor ornamentals

URMULE projects underway

There are nearly 20 projects underway looking at various insecticides, fungicides and herbicides for use on outdoor ornamentals. Some examples include aphids on Christmas trees, black vine weevil, spruce spider mites, viburnum leaf beetle, downy mildew, Gymnosporangium rusts, Phytophthora and Pythium, tar spot on maple and weeds on Christmas trees. I will circulate the registration announcement and final labels as I receive them.  

New edition of Nursery - Landscape Production and IPM

This fall the 2009 edition of OMAFRA Publication 383, Nursery and Landscape Plant Production and IPM was printed. The new guide follows the same format with chapters on pesticide safety, water, media and soil, pest management and weed management. Many of the images have been replaced with those of superior quality, including some by our University of Guelph M.Sc. student, Dave Cheung. Guides may be purchased for $20, by calling 1-800-668-9938. If you order five or more publications, you receive a 20 per cent discount. 
Jen Llewellyn may be reached at 519-824-4120, ext. 52671, or by email at jennifer.llewellyn@ontario.ca. See her Nursery-Landscape Report: http://apps.omafra.gov.on.ca/scripts/english/crops/agriphone/index.asp