Back Maximising maize silage yields

Date: 25 June 2014

During the past two decades maize silage has been an increasingly popular supplementary feed option for New Zealand farmers. Proven and profitable, maize silage provides high quality feed at a cost-effective price.

It is not surprising local maize acreage has increased due to all of the commercial crops grown globally; maize is the most efficient at converting sunlight, nutrients and water into high quality, low cost feed.

Results of the last five years Product Advancement Trials, run by Pioneer® brand products and is located from Northland to Canterbury, show maize has performed exceptionally well. Yields greater than 25 tDM/ha were achieved in 1,731 plots and yields greater than 30 tDM/ha were achieved in 317 plots. Trial yields greater than 35 tDM/ha are not uncommon. It is this high yield potential of maize that allows most New Zealand farmers to grow crops yielding 18-26 tDM/ha for 15-21 c/kgDM in the stack. So what are the key steps to achieving high maize silage yields?

Choose a good paddock.
Choose a flat to rolling paddock with good access and relatively even contour. Paddocks that are too wet should be drained prior to planting since maize yields will be lower if soils are waterlogged.

Soil test.
Take a 150 mm deep soil test prior to planting to determine nutrient application rates. Recent research has shown that maize silage crops that are planted in paddocks with a history of effluent application may require no additional fertiliser, although a soil test should always be taken.

Plant early.
Maize can be planted as soon as the 9am soil temperature is 10â—¦C at 50 mm for three consecutive days. Research has shown that early planted crops will yield more than crops planted too late in the season. The ideal planting date will vary from region to region. Talk to your merchant representative or Pioneer Area Manager for paddock-specific advice.

Choose the right hybrid.
Hybrid selection will have a huge impact on crop yield potential. So how should you go about selecting the right maize silage hybrid?

1. Choose a hybrid that has the right maturity and agronomic traits (e.g. drought tolerance, disease resistance) for your growing environment.

2. Purchase high quality New Zealand produced seed from a company that has ISO certified quality control systems in place.

3. Look for high drymatter yields. Hybrid selection decisions should be based upon maize silage yield summary data. Usually at least 20 comparisons of hybrids planted side-by-side in the same paddock, over several seasons are required for the yield difference to be statistically significant. This means you can be confident the yield advantage is due to hybrid genetics, rather than other factors such as differences in the growing environment or sampling errors.

4. Consider nutritional quality. From a nutritional standpoint, the best silage hybrids will have high grain yields because grain is highly digestible, and supplies 80% more energy than stover on a kilogram for kilogram basis.

Plant at the recommended population.
Modern maize hybrids have enhanced stress tolerance making them more adaptable to planting at higher populations. Pioneer research conducted in New Zealand has shown that higher populations will deliver higher yields without compromising silage feed value1. Ensure that your seed bed is even and weed-free to ensure good seedling establishment.

Use insecticide treated seed.
Insects reduce the yield potential of the maize silage crop by reducing the plant population. The best way to control Argentine Stem Weevil and Black Beetle is to plant Poncho®2 treated seed.

Control weeds.
Make sure your maize management includes a comprehensive weed control programme. Scout crops regularly, especially prior to row cover, (the point where the plants in each row cover the ground) and spray if necessary.

Crop walks
Regular crop walks, especially during the 6-8 weeks after planting will help ensure that any nutrient, weed or insect issues are identified so they can be corrected in a timely fashion.

Once the maize has reached row cover, the frequency of crop walks can be reduced. Growers can virtually sit back and watch their maize grow!


1Densley et al, 2003. The effect of increasing plant population in maize silage yield and quality. Proceedings of the NZ Grasslands Association 65: 117-121.
2Registered Trademark of Bayer CropScience.


Raewyn Densley
Forage and Nutrition Specialist