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To quantify weed seed persistence, production and dormancy in vegetable crops - HH2011SFV

It is well known that weeds affect the yield and quality of vegetable crops. The soil seedbank is the most important source of future weed populations and may consist of several main species, each with specific requirements for successful germination and emergence. Most control measures are intended primarily to deal with weeds in the growing crop, but weed management should be considered a long-term strategy. Failure to address this issue will lead to increasing weed problems and will compromise the sustainability of organic growing systems and those using reduced chemical inputs.

To predict how current weed control strategies will influence future weed populations, we need to know how many seeds are returned to the soil, both by weeds that are allowed to remain because they have a negligible economic effect on the current crop and those that survive through resistance to the control measures. The persistence of these seeds within the soil seedbank and their unique dormancy cycles have a profound effect on the composition of weed populations long after the parent plants have been removed.

Identification of a simple direct relationship between seed production and plant weight would allow a model of weed reproductive effort to be linked readily with the models already developed at HRI simulating crop-weed competition, seed movement and weed seedbank dynamics. The model would predict the quantity of weed seed produced annually in a given area, taking into account seed production by both the weeds in a growing crop and those that may develop in the period between crops. Non species specific models for weed seed persistence and for their ability to emerge from depth based on seed size, soil moisture and temperature will also be developed as part of this project.

Combining the models described above with a greater understanding of the underlying dormancy cycles of key weed species will improve the seedbank dynamics modelling framework under development at HRI. These developments will improve the application of the dynamic model to a wider range of weed species.

1. To determine the effect of plant competition on seed production by some common weed species of field vegetable crops.
2. To determine the underlying cycles of induction and loss of dormancy in some common weed species of field vegetable crops.
3. To determine the effect of temperature , moisture and weed seed size on seed persistence in the soil.
4. To determine the effect of weed seed size on the ability of a seed to germinate and emerge from a given depth.
Project Documents
• Final Report : To quantify weed seed persistence, production and dormancy in vegetable crops   (653k)
Time-Scale and Cost
From: 2000

To: 2003

Cost: £379,937
Contractor / Funded Organisations
Horticulture Research International
Fields of Study