Top tips for a successful maize harvest

The maize harvest will soon be upon us and the Maize Growers Association’s John Morgan has provided our members with some top tips for getting the most out of every kernel.

As with all major jobs on farm, planning pays. A wet March and April, followed by very dry conditions, has resulted in a varied crop. Maturity of whole maize forage, whether for livestock feed or anaerobic digestion (AD) feedstock, is measured as a percentage of whole plant dry matter (DM).

The maturity of maize silage is important as it drives animal intake and the proportion of plant energy present as grain starch. As a rule of thumb, the higher the DM at harvest the greater the palatability of the forage and the higher the starch percentage.

The more palatable the silage the less concentrate is needed as starch is a key driver of milk quality and weight gain. However, if maize is allowed to overmature the digestibility of the grains is restricted and it’s harder to achieve stability in the clamp.

The palatability of forage or starch levels for AD feedstock maize is less important, meaning it can be cut a little earlier than forage maize. Target maize maturity for livestock silage is 32% with a range around 30 to 34% deemed acceptable. For AD the lower limit of maturity can be set at 28% DM.

Research shows forage typically dries down at about 2% DM per week. Assessing DM percentages early, around mid-August and using the 2% per week dry down rate, allows harvest plans to be drawn up in good time for both on farm and contractor partners.

Whole plant DM percentage is best assessed by drying a representative sample in an oven overnight, at 60 degrees for 24 hours or until the weight of the sample stops falling. You can also use an air fryer or the infield milk line system.

Chop length and cutting height are additional considerations. Length requirements will vary depending on the proportion of forage in the livestock ration. For high-concentrate dairy rations, more than 50% of concentrate, longer chop of above 15mm may be useful to provide valuable structural fibre. For lower concentrate rations and AD feedstock, maize should be fine-chopped to maximise surface area to support the rumen bacteria.

Cutting height also has an impact on the energy concentration of the forage. The higher the cut the higher the proportion of grain to leaf and stalk and the higher the energy density. However, the higher you cut the more crop is left in the field and the less overall forage you will end up with.

Driving heavy farm machinery on potentially wet and structurally weak soil needs to be thought about carefully. Wheeled machines should be fitted with flotation tyres and pressures should be set as low as manufacturers recommend for the weights being carried.

Immediate action to remove harvest compaction and break channels likely to take subsequent rainfall from the field should be planned well in advance. As a guide, if the ground can take forage and trailers it can take a cultivator on the same day, to remove compaction and break runoff channels. Post-harvest establishment of commercial or cover crops, assuming soils will not be damaged by heavy establishment equipment, will, once up and running, hold soil within the field and take up nutrients, particularly nitrogen, that might otherwise be leached.

Rapid growing cover crops including Italian Rye Grass provide an opportunity for some early grazing or a silage cut, but remember the cover needs to be gone in well before the next spring crop. The earlier post-harvest crops can be established the better.

For more advice on getting the most from your maize harvest ring the Grass & Forage Line on 01769 576232