Knowing where black-grass patches are throughout the field is the first step in understanding the extent of the problem and how best to tackle it. Mapping black-grass stricken fields before seed shed means you can take control before the problem gets worse.
Here are six reasons black-grass mapping is important:
This means control can be prioritised, leading to more targeted herbicide applications and reducing overall costs. Mapping will identify problem patches throughout the field so that they can be located during periods when they are harder to spot, for example when weeds are young and susceptible to selective herbicides
Mapping will give you a point of comparison for future populations, so you can keep tabs on your progress with black-grass control. Knowing where you are having success and identifying where control might be slipping is the key to building a control programme that works year-in, year-out.
Black-grass prefers heavier soils with high water retention, and the presence of the weed can indicate underlying problems with drainage and soil structure. Comparing black-grass with other types of maps will help identify problems that need solving. Typically, improving drainage and targeted cultivation to remove compaction will help with black-grass control.
Cultural control methods can be targeted to mapped spots, such as deciding where to prioritise stale seed beds, and where an increased seed rate can be applied for better competition during drilling, particularly in heavy soils.
Black-grass seed is often spread through contaminated harvest machinery or balers. Mapping can help you understand how it moves around and plan accordingly. For example, the worst hit fields should be cultivated last to discourage seed travel, and all kit should be cleaned between fields.
Mapping helps to identify if pre- and post-emergence herbicide treatments have been successful, and whether resistance to certain herbicides may be developing. This can alert you to revise your control programme and consider carrying out a resistance test on surviving weed seeds. It will also identify areas in which glyphosate can be applied to any surviving black-grass patches before seed shed.
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