Standing in a soil pit at a recent CropNuts and Cereal Growers Association Field Day near Eldoret, I asked how many farmers have Brome Grass on their farms. I was surprised when around three-quarters of farmers raised their hands and they looked around in slight embarrassment!
The fact is that this is a very common weed in many of the major cereal growing areas of the country. Its appearance in wheat – and maize – fields in not surprising when you consider that it is a similar species of plant to wheat and barley, so thrives under the same conditions.
Left unchecked, Brome Grass is highly competitive and can easily reduce crop yields by half.
Many common herbicides are either not very effective, or the plants have developed resistance from repeated use. Pendimethalin (e.g. Twigamethlin, Stomp) is chemical that offers limited control, and Pallas is another chemical that in many parts of the world is no longer effective due to resistance.
But why the soil pit? Cultivations and soil management has a big impact on Brome, but it is important to know what species you are dealing with.
Rye Brome (above left) is very common. The seeds are larger, and when you hold the seed head up to the light you can see the gaps around each seed.
Rye Brome seed is not fully mature when it is shed, so you should leave the seed undisturbed on the surface for a few weeks before cultivating. This avoids the seed becoming dormant and surviving for several years.
Sterile or Barren Brome (above right) has longer “awns” or hairs on each seed. If you have Sterile Brome on your farm it is advisable to lightly cultivate immediately after harvest to encourage the seeds to germinate. The cultivation only needs to be very light – just a harrow – you can then run cattle over the shamba, and cultivate more thoroughly to restructure the soil just before planting.
Rotation remains the best tool for controlling grass weeds; alternating broad leaved crops such as Canola or Peas allows different – and very effective – herbicides to be used.
Contact your local CropNuts Agronomist to discuss weed management further, or send a sample of Brome seed into our lab with your soil samples to have it identified.