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Understanding the relative establishment times of crops and weeds within the changing seedbed - HH3406SX

The primary purpose of this project is to understand the basis of variation in the relative seedling emergence times of crops and weeds using field experiments supported by simulation modelling. This will be used to identify implications for weed control practice and the potential for their improvement. This is because in the past there has been extensive use of herbicides by farmers as they have been relatively inexpensive and very effective for weed control. However, there has been increasing concern about their use due to their negative impact on both food safety and the environment. In addition, as a result of EU 91/414 the range of herbicide products available for use in horticulture is in decline leaving serious gaps in weed control, causing difficulties for growers, particularly those of more specialist crops. The problem is that no weeds are tolerated within horticultural crops because of their negative impact on yield and quality, however growers are expected to be able to absorb these increasing constraints in their weed management options whilst maintaining stringent quality standards. Improved targeting of the products that are remaining available to growers and improving the reliability and efficacy of non chemical methods will contribute towards alleviating this problem. In meetings these aims the project will benefit both conventional and organic growers. The recent defra review, HH3403sx, identified that a better understanding and quantification of the relative emergence times of both crops and weeds was a knowledge gap and research priority that would help to meet this need. This is particularly true for the major drilled crops such as onion and carrot where weeding strategies are often focused on the crucial early stages of crop establishment. The most efficient approach is to focus the project on the two major drilled crops, carrots and onions, to develop this generic understanding, the principles of which can then be adapted to other minor crops. A secondary purpose of the project is to put in place a dynamic modelling framework of weed biology and ecology for two important weeds in horticulture (Tripleurospermum inodorum and Stellaria media), through the integration of existing published models. The framework will be used to simulate the impacts of a range of weed management strategies on their long-term sustainability and thus help identify both beneficial and detrimental strategies. This project contributes towards defra’s objective to “promote a sustainable, competitive and safe food supply chain which meets consumers' requirements”.
Objectives:The overall aims of the project will be achieved by completing the following four objectives:-1. To complete field experiments to quantify variation in the relative timing of crop and weed emergence and the subsequent impact on crop yield.2. To adapt existing simulation models to generate scenarios of crop and weed emergence in the same seedbed and hence extend and generalise the results from field experiments.3. To improve understanding of the basis of variation in the relative timing of crop and weed seedling emergence and establishment and to use that understanding to identify methods for improved weed management (relevant to both conventional and organic systems) in drilled field vegetables 4. To build on an existing suite of published models by developing a model framework of weed biology and ecology which will help provide insight to the long-term impact of weed management strategies.
Time-Scale and Cost
From: 2004

To: 2008

Cost: £673,313
Contractor / Funded Organisations
Warwick - HRI
Allocated - WHRI              
Sustainable Farming and Food              
Sustainable Production