Advice on assessing maize maturity as harvest fast approaches

The August heatwave has accelerated maize maturity and with harvest now fast approaching, growers are being advised to check crops.

Following the drought of 2018 more maize has been planted and there are some very bulky crops that are maturing nicely following the good weather at the end of August, says Neil Groom, technical director of Grainseed.

In fact, crops have performed well all season.

“We had good weather at drilling allowing contractors to get on and most crops were drilled into excellent seed-beds. Warm weather ensured fast germination and the only challenge was finding wind-free days to put the herbicide on,” he adds.  

See also: Why drilling maize deeper and later could be future trend

Check crop maturity

During good weather in September crop dry matter can increase by 4-5% a week.

Therefore, Mr Groom says growers should keep an eye on crops as they approach harvest and let contractors know how crops are maturing, with the aim of harvesting the crop at the optimum dry matter for clamping and feeding of 32%.

It is difficult to estimate crop dry matter by eye, since modern varieties will have fully ripe grains on a plant that is still green to maximise plant digestibility.

New work by the Maize Growers Association has shown that air fryers can give an accurate dry matter result in just 90 minutes and can be done on farm (see below). Or samples can be sent to a lab for oven dry matter determination in 24 hours.

Step-by-step guide to assessing dry matter with an air fryer

Step one: Visit all your fields, walk well into the crop and off the headland. Choose five points to cut.

Step two: Use a garden shredder to chop the plant and collect in a bucket underneath or alternatively use secateurs. Mix all five plants together in a larger container.

Step three: Split samples into small enough portions to fit in the air fryer and weigh the fresh weight using a scale (make sure you subtract the weight of the plate or dish).

Step four: Put the sample in the air fryer on full for 15 minutes. Remove the drawer and stir the sample before heating on half power for another 75 minutes. Stir the sample every 15 minutes.

Step five: Re-weigh the sample and calculate the dry matter by following the calculation below:

DM% = dry weight (g)/fresh weight (g) x 100

Preparing for harvest:

  • Estimate your maize yields and plan where the maize is going to be clamped. Many clamps are already full with grass.
  • Maize can easily be ag-bagged or clamped in the field since, when mature, there is no risk of effluent. But you need to inform the Environment Agency and site must be at least 10m away from a watercourse.