Organic Agriculture Centre of Canada

Faculty of Agriculture

OSC Activity B.4

Low-tillage grain production systems that suppress weeds and minimize tillage

Activity Researchers

Name	Affiliation
Martin Entz, Lead Researcher M_Entz@umanitoba.ca	Professor Department of Plant Science University of Manitoba Winnipeg, Canada R3T 2N2
Robert Blackshaw, Co-applicant Blackshawre@agr.gc.ca	Research Scientist Agriculture and Agri-Food Canada Lethbridge Research Centre 5403 - 1 Avenue South P.O. Box 300 Lethbridge, AB T1J 4B1
Steve Shirtliffe, Co-applicant steve.shirtliffe@usask.ca	Associate Professor Department of Plant Sciences University of Saskatchewan 3D04-51 Campus Drive Saskatoon SK S7N 5A8

Objectives

To test different reduced tillage implements in green manure fallow systems.
To test different plant species combinations for producing mulches for no-till organic systems.
To study mulch decomposition in a long-term field study.
Using the information from this study, make recommendations on reduced till organic systems for farmers and extension workers.

Activity Summary

Tillage has traditionally played a vital role in organic cropping systems in Canada and around the world. Besides providing weed control and seedbed preparation, tillage facilitates important soil-building practices in organic systems, such as including perennial crops and annual green manures in rotation. However, growing awareness of the value of reducing tillage in crop production systems has led researchers in various parts of the world to consider the potential of low-till organic systems.

This project will investigate no-tillage and reduced-tillage systems in three distinct Canadian prairie ecozones, ranging from subhumid to semiarid. We will develop systems that allow a minimum 50% reduction in tillage for organic farmers.

The first project compares no-tillage and low-tillage machine options in green manure management. Green manure crops are grown for their nitrogen (and other) benefits and are vital to successful organic grain production. Green manures are typically terminated using tillage. We will test the wide blade cultivator, an implement that was developed in the 1930’s in response to wind and water erosion. This machine undercuts plants, resulting in maintenance of soil cover. We will also test the newest machine innovation for reducing tillage in organic production – the blade roller. This machine crimps the stems of plants, killing them without dislodging the roots. Two other termination approaches will be tested – the flail mower and standard tillage. The experiment will be conducted under subhumid (Carman, Manitoba), dry subhumid (Saskatoon, Saskatchewan) and semiarid (Lethbridge, Alberta) conditions. We will determine how effectively the machines terminate the green manure crop, plus how the machines affect soil water conservation, weeds, nitrogen availability from the green manure crop and grain yield of following crops.

The key to reducing tillage in organic grain production lies in avoiding weed growth. Mulches, consisting of dead plant material, are one way to reduce weed growth as mulches smother weeds. The longer the mulch from a green manure crop lasts, the longer soil tillage can be avoided. Mulches can be created with both the blade roller and wide blade cultivator. In this second major study, we will study how best to “construct” mulches so they last longer. We will test the hypothesis that adding more plant species to green manure crops will produce more vegetative biomass than can be mulched. We will also determine whether adding fibrous plants to the plant mixture can slow mulch decomposition. Again this study will be conducted at Carman, Saskatoon and Lethbridge. A complementary study will investigate decomposition of various mulches.

This research will provide both applied and basic information about reduced tillage systems. The research will provide an in-depth analysis of the biological and physical processes associated with reduced tillage in organic agriculture. By better understanding how different green manure termination approaches affect the entire cropping system (N, weeds, water), the research will provide critical knowledge to farmers and extension workers.