A new sophisticated web-based tool to help oilseed rape growers accurately assess the need for nitrogen and growth regulation and hence manage their oilseed canopy more effectively has been launched by BASF and ADAS. The Canopy GAI tool can be found on www.totaloilseedcare.co.uk web site and is available free to farmers and advisors.
"Canopy management in oilseed rape in the spring aims to create an optimum sized canopy that is able to maximise the crop's yield potential. It involves tailoring early spring inputs to the state of the crop, its canopy size, its plant population as well as seasonal and environmental factors. But you need to be able to accurately assess when and where inputs are needed. This is where the Green Area Index (GAI) comes in. The GAI is the ratio of green tissue area to ground area and it is an effective measurement of assessing canopy size. Economic benefits from plant growth regulators have been observed in crops that have a GAI greater than 1.0 in March or crops with a GAI greater than 2.0 in April," says Diane Heath, BASF Oilseed Rape Product Manager.
"In the past, growers have assessed GAI visually. Last year we provided a series of reference photographs with their estimated GAI's with which growers could compare. This year the new computer-based tool is calibrated to measure GAI much more accurately and is the first of its type. Developed by ADAS and BASF, the new web-based tool allows growers to upload photographs of their own oilseed rape crops and it will instantly relay back to them the Green Area Index (GAI) for individual fields. It really is an important advancement in managing canopies effectively," explains Ms Heath.
"Farmers and advisors can go on-line on www.totaloilseedcare.co.uk at any time to upload their own photographs and they will receive an accurate assessment of GAI on the screen within a few seconds. To gain the most accurate results, digital photographs should be taken directly above the crop and ideally cover an area of 1 metre by 1 metre. It is also advisable to avoid taking photographs when it is sunny, as this causes shadows. The web site will still carry a number of reference crops in a number of locations with measured GAIs, as before."
The Total Oilseed Care web site also offers up to date advice on growth regulation with Caramba (metconazole) as well as key information on all BASF rape products. "Many winter oilseed rape crops with over-large canopies this year will benefit from growth regulation with Caramba, as well as reduced or delayed nitrogen applications. Crops established well this autumn and were advanced going into the mild winter. Without effective canopy management, most crops will have flowering canopies in the summer that are inefficient at intercepting sunlight and be unable to reach their yield potential. The more forward ones will also have a high lodging risk," says Diane.
"With top class growth regulation and disease control properties, Caramba restricts canopy size and keeps it disease free. A well-managed canopy produces more seeds per pod and bigger seeds, leading to higher yields. Caramba also produces more uniform flowering over the main and side racemes, leading to even ripening and less pod shatter. For growth regulation, Caramba should be applied at mid-stem extension stage when there is sustained active growth and the weather is warm. We would expect a very high proportion of crops to show an economic response to growth regulation this spring and would hope that the new GAI tool will help in the more effective Spring management of this profitable crop," says Diane Heath.
To complement this new web-based tool, BASF and ADAS have also produced a new 22-page booklet for 2007, Optimising Canopy Management. This new booklet outlines all the key issues of canopy management, illustrates over 30 colour photographs of reference crops with different GAI's and different plant populations at different times of year and advises on the best course of action. Copies of the new reference booklet can be obtained from BASF on 0161 488 5783.
