The hot and dry conditions experienced this growing season are set to bring maize harvest dates forward considerably, as well as impacting yield in some cases.

Wynnstay crop protection manager Dr Simon Pope urges growers to assess crop maturity from late August onwards, to avoid being caught out by crops maturing earlier than normal.

image expired

“Maize harvest date will always vary across the country depending on whether the crop is grown in a favourable or less—favourable area, and the FAO number of the variety will also have a bearing,” says Dr Pope.

“The extreme weather conditions this season could push crops to mature much earlier than would normally be expected, so harvest dates will probably need to be brought forward to reflect that.

“The FAO number of a variety relates to the number of heat units it must accumulate in order to reach maturity,” Dr Pope explains. “Given the extraordinary temperatures that have occurred this growing season, we should expect an unusually early maize harvest, especially for early varieties with a lower FAO number.”

He recommends checking crops regularly to assess the stage of maturity and speaking to contractors to arrange for harvest to be brought forwards if necessary.

“While there is little doubt that an early maize harvest is on the cards, the impact of the growing conditions on yield will be more variable. 

“Maize likes warm weather, but the plant also requires sufficient moisture and lack of rainfall has had a negative impact on some crops this year, with several showing signs of suffering from fairly extreme drought stress,” notes Dr Pope.

“As the saying goes, we should expect maize to be knee high by the 4^th of July, but this year some crops were not much above knee-height by early August. And many of these crops were showing tightly rolled leaves, indicative of drought stress. Unfortunately, yield potential is likely to be compromised for such crops. 

“However, at the other end of the spectrum, there are many crops that demonstrated good early vigour, and which were able to establish adequate, deeper root systems, which then enabled the plants to cope with the lack of moisture in the surface layers of the soil. These crops have thrived in the sunshine this year.”

To a certain extent, in a favourable season the maize plant can tolerate some underlying issues. However, Dr Pope suggests that when growing conditions become more difficult it quickly becomes apparent where there are problems with low pH, inadequate nutrition, or where compaction has not been addressed and these criteria then become the biggest driver behind crop outcomes.

“Any agronomic concerns with soil condition or crop nutrition which hold back root development will have resulted in plants being less able to access moisture in the soil when it was needed,” he notes.

“It becomes a vicious circle, if the roots can’t develop normally the plant is not supplied with the moisture and nutrients it requires to enable the roots to develop and grow. Without a strong, healthy, well developed root system the plant will struggle when conditions become difficult.

“It’s been a year which demonstrates how vital it is to pay attention to detail during crop establishment, to achieve the desired results at harvest,” he concludes.