Maize harvest

Published 21 September 12

DairyCo extension officer Tom Goatman and John Morgan from the Maize Growers Association (MGA) talk about preparing for maize harvest.

Preparation for forage maize harvest is now rapidly approaching and it is worth considering a number of points in order to maximise silage quality.  Key issues include when to harvest, how short to chop the crop, ensuring grain crackers are adjusted correctly and the use of additives.

"The optimum time to harvest is when the maximum starch yield has been reached, balanced with optimum dry matter (DM) to aid consolidation in the clamp," says Tom. "The aim should be to try and achieve a DM of 30-35% but unfortunately this is likely to be difficult in many areas given the situation this year.  Because of the poor start many crops experienced, subsequent high rainfall and lack of sun, much of the 2012 maize harvest will struggle to reach maturity and optimum DM before the end of the harvest." See Forage for Knowledge 5th Sept.

At harvest it is important to check that the grain processor (corn cracker) is functioning correctly. This must be carried out during the harvesting process so any problems can be corrected early on and monitored as harvest continues.  The kernels of immature maize will require minimal processing. However, it will be important to monitor what is coming out of the harvester into the clamp, that this is of the target particle size and that >90% grains are broken.

Following the poor weather over the summer and with the potential for cool wet weather over the coming weeks you may find that use of an effective additive should be considered.  Additionally an additive should also be considered if there is a risk of soil contamination.

"Ensure good clamp management during harvesting and ensure the clamp is sealed well," Tom says.  "Consider the use of an oxygen barriersheet, as well as a normal sheet, to ensure an air tight seal.  Attention to detail to all aspects of harvesting through to sealing will ensure clamp losses are kept to an absolute minimum.

"Once harvested early analysis will be important in initially assessing the nutritional quality of the crop and inform wintern ration planning.  Regular sampling over the winter period will be necessary in order to monitor nutritional quality changes and avoid ration imbalances."   

John Morgan from the MGA says, "Raising the cutting height will improve quality of silage as the lower parts of the stem are of low feed value.  The downside of raising cutting height is that overall yield is reduced.  A balance needs to be struck between quality and quantity.

"I'd suggest lower maize chop lengths," John continues "Most maize is chopped at 12mm with typical longer chop maize at 18 - 22mm.  Actual chop length would depend on the place of maize in the ration.  A chop length of more than will be difficult to consolidate and forage intakes may suffer.  A chop length of 5mm or less chop would be too short."