Attention to detail can increase maize yield

Growers wanting to increase maize grain and silage yields and profits should focus on seedbed preparation, planter set-up and crop monitoring, says Foundation for Arable Research maize researcher Rene van Tilburg.

FAR maize researcher Rene van Tilburg.

Average maize yields in New Zealand are 12 t/ha for grain and 21 t/ha for silage. In comparison, record yields have been up to 23.4 t/ha for maize (Pioneer Cup results) and up to 30 t/ha for silage.

“To improve their averages, growers need to monitor and manage potential yield and profit robbers; particularly poor and uneven establishment, inefficient nutrition, water stress and pests. Weather is obviously a significant contributor to yield, and while it cannot be controlled, taking temperature, rainfall forecasts and sunshine hours into account when making crop management decisions will contribute to efficient systems and maximum profits in any given season.”

The common themes among yield record-holders worldwide are effort around seedbed preparation, planter setup and crop monitoring. “For example, world record holder (United States grower) David Hula says that 65% of the yield potential is done when the planter leaves the field.”

The perfect crop is considered to be one where all plants emerge within 12 or 24 hours of each other, depending on the prevailing temperature at the time.

“As growers, your job is to question (and dig) for the reason any seed is slow to emerge or does not emerge at all. After emergence is complete, dig in the gaps and look for misses caused by pests such as cutworm, wireworm and Argentine stem weevil. These are one-off losses, with remaining plants likely to go on to reach their potential.”

Uneven germination can be more problematic. It may be caused by poor seed-to-soil contact, poor soil structure, dry conditions, variable planting depth, side wall compaction or a smeared seed trench. “Maize plants will not ‘grow out’ of these problems, which will rob yield right up to harvest.”

Understanding soil fertility and nutrient interactions is also important. Oversupply of NPK (nitrogen, phosphorus and potassium) is not the path to success, and phosphorus application without consideration of other nutrients, particularly zinc, can depress yields, Rene van Tilburg says.

“Soil test regularly; smaller grids are better than large ones. While there are different methods of trace element testing, choose one and stick with it. Consider regular tissue testing from V6. Get expert advice on results. A deficiency or excess can have knock-on effects on other nutrients, leading to misleading conclusions. Record all inputs, weather conditions, soil and leaf test results, along with yield, every year. This database will allow you to observe how any differences in weather or inputs between seasons impact on yield. If you are making changes to your system, only change one thing at a time...this will allow you to understand its impact. It’s a long game.”