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Manipulation of grass weed seed dormancy: Improved stale seedbed control resulting in lower in crop grass weed populations - PS2148

Grass weeds in general, and black-grass in particular, are a major concern to UK arable growers as they pose an increasing problem in weed control and effects on crop yields. Stubble burning, banned in the UK in 1993, was a practice that improved grass weed control largely due to the breaking of seed dormancy resulting in weeds germinating prior to crop planting. This allowed control to take place prior to crop planting, in stale seedbeds. Currently there is a growing call from UK farmers for a return of stubble burning to aid them in their control of black-grass. It is however highly unlikely that this will take place due to both environmental and health and safety concerns relating to the practice.

Recent research at Harper Adams University College has identified seaweed extracts that very successfully break dormancy in black-grass seeds under laboratory and glasshouse conditions. Unlike traditional methods for breaking dormancy they are not environmentally unsound or financially unviable. Additionally there have been a number of reports demonstrating the dormancy breaking properties of smoke-water. This raises the possibility that the dormancy-breaking effect of stubble burning might be more than just a thermal effect

Dormancy in black-grass varies greatly from year to year, largely due to environmental conditions during seed production. This makes the use of stale seedbeds prior to crop establishment highly unpredictable and varied between years. It would be highly beneficial for farmers to have the ability to improve germination of grass weeds in stale seedbeds by manipulating seed dormancy. This would allow non-selective controls to be used to eradicate both herbicide-susceptible and herbicide-resistant weeds, reducing the pressure on a limited and dwindling number of in-crop herbicides.
This research programme investigates novel solutions to weed management that address Defra’s Business Plan Priority 1 “to support and develop British farming and encourage sustainable food production”.

The research will result in more successful weed control and subsequently greater yields without the increased need for conventional in-crop chemical controls. It may actually result in a decreased need for in-crop chemical controls and the reduction in herbicide usage. In addition, better control in stale seedbeds will address both herbicide susceptible and herbicide resistant weeds, addressing the endemic problem of herbicide resistance to ACCase and ALS type herbicides in black-grass populations in the UK as part of sustainable integrated management strategies.
Evidence Objective 1: Comprehensive literature review (carried out at HAUC)

Evidence Objective 2: Effects of seaweed extracts on grass weed dormancy (controlled environment studies) (carried out at HAUC)

Evidence Objective 3: Effects of smoke-water on grass weed dormancy (controlled environment studies) (carried out at HAUC)

Evidence Objective 4: Effects of seaweed extracts on grass weed dormancy (field studies) (carried out at HAUC and SAC)

Evidence Objective 5: : Effects of smoke-water on grass weed dormancy (field studies) (carried out at HAUC and SAC)

Time-Scale and Cost
From: 2012

To: 2015

Cost: £169,920
Contractor / Funded Organisations
Harper Adams University College, SAC
Herbicide use              
Fields of Study
Pesticide Safety