Maize Watch: Warmer weather maturing crops nicely

As maize maturity is progressing with the current warmer weather, farmers need to prepare their harvest plan and check crops regularly, so they can cut at optimum dry matter.

“In early September we often see dry matters increase faster than the average of 2% a week because the temperature is still warm, especially if there are drying winds too,” explains Neil Groom, technical director at Grainseed.

“This week we can see that the Farmers Weekly farms in the South and East have gone up by 3% or 4%, so I advise growers to look at their fields twice a week so that they can cut at the optimum of 30-35% dry matter. At this level the sugars have been converted to starch in the grain and you can get good consolidation in the clamp.”

See also: 5 steps to make the most of maize in feed

Optimum timing

If crops get too dry it is difficult to squeeze the air out in the clamp. Chopping shorter and layering the silage in shallower depths will help, but it is best to get the crop cut at the optimum time.

At high dry matters, it is also advisable to use an additive to reduce aerobic spoilage during feedout.

Mr Groom suggests farmer should be making a harvest plan now, including:

  • If fields are accessed via narrow lanes, creating a one-way system back to the pit which will help trailer flow
  • Cutting hedges around gateways to improve visibility
  • Filling in potholes in gateways
  • Clearing the yard to improve access to the pit.

Clamp management

“The buckrake driver should control the whole harvesting process since that’s the most important job: squeezing oxygen out of the clamp,” says Mr Groom.

The MGA’s rule of thumb is that you need 25% of the weight arriving in the clamp every hour to be rolling the pit. So if you have six loads weighing 18t (108t in total) arrive every hour, you need 27t of steel rolling the clamp. Most loaders weigh 12-14 tonnes, so you need at least two machines pushing up and rolling.

Pay particular attention to the edges alongside the walls and shoulders of the clamp to get good consolidation. Some contractors use blades and compaction rollers to ensure better clamping.

The clamp should be sealed using an oxygen barrier wall film and top film, netted against vermin and weighted down with gravel bags around the edges and joins so that the material ferments rapidly and creates anaerobic conditions to preserve the silage.

Maize Sampling


Drill date

Height above sea level (m)

Crop dry matter 2 September

Increase from previous week

Petworth, Sussex

27 April




Harleston, Norfolk

30 April




Crediton, Devon*

22 April




Ticknall, Derbyshire

25 April




St Clears, S Wales*

24 April




SRUC, Dumfries, Scotland**

6 April




Variety is Es Ballade except where noted. *Variety Es Lovely. **Under plastic, variety Es Marco