Check maize is mature before harvesting, expert advises 

Maize drilling usually occurs in April, but April 2024 was the sixth wettest for the UK since records began in 1836, so many growers were delayed until May.  

Dr Simon Pope, crop protection manager at Wynnstay, said: “Some maize may have been drilled in less than ideal conditions in April, and some may have waited for better conditions in May. 

“If maize is sown under good conditions, it’s easier to produce a good crop, but if it is sown under poor conditions, it becomes much more difficult to get a good outcome at harvest.” 

Growing maize for starch 

The summer of 2024 has been the coldest since 2015, however, the recent spell of warm weather in August should help to bring harvest back on track, but producers should make sure the maize is actually mature before harvest.  

“It’s really important to check the crops are at the right stage of maturity. The dry matter target is 32% for forage maize.  

“Just because your neighbour is harvesting, doesn’t mean you should be,” said Dr Pope. 

An immature crop will have lower starch levels. The expert added: “The whole point of growing maize is for the starch. As the crop matures, starch forms in the kernels. 

“If a crop is cut too soon, the process of cob-filling will not be complete, and the silage will have lower nutritional value.”  

Check for maize maturity 

Conversely, if the crop is too mature, there needs to be careful consideration when cutting. 

Dr Pope added that farmers should make sure that the processor on the chopper is set up correctly to ensure that every kernel is cracked, to allow the bugs in the rumen to access the starch. 

If the kernels are bullet hard they are more difficult to process, increasing the risk that grains could pass straight through the animal. 

Wynnstay expert said that there is a simple way to check for maize maturity.  

“Break off a few cobs that are representative of the crop, strip the sheath off, snap the cob in half and squeeze the grains from the broken surface halfway down the cob.  

“If when you squeeze them they squirt, it’s not ready. A little bit of moisture is fine, but anything more than that then it’s not ready to chop. 

“It’s also possible to cut the plants around six inches above ground and wring the stems like a tea towel. If a lot of liquid is squeezed from the crop, it could probably benefit from longer in the field,” he explained. 

Preparation is key 

Producers should consider chop length when it comes to cutting. Dr Pope said: “A longer chop is often favoured from a feeding point of view, but a shorter chop allows for easier consolidation and better fermentation with lower levels of aerobic spoilage. 

“Speak to a nutritionist to find out what sort of chop length is needed to suit the ration. An additive might bring advantages, too.  

“With maize, a lot of attention is devoted to growing the crop, if as much attention to detail was paid to the harvesting and subsequent pit management to reduce waste and losses, there would be more forage of higher quality to feed out.  

“An additive is a way of protecting the investment that has been made throughout the growing season.” 

Dr Pope added that by using the right additive, growers can reduce fermentation losses by 50%, so there’s more dry matter to feed and silage is of a higher feed value, compared to untreated crops. 

“Get everything set up ahead of time, and if we get a weather window as the crop reaches the ideal stage for chopping, then growers can make the most of it,” he concluded. 

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