Maize for Silage
Technical
Insight 325

SELECTING A MAIZE SILAGE HYBRID

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HYBRID MATURITY

For most growers the period of time a maize plant takes from planting to silage harvest is the first consideration when selecting a maize silage hybrid. A number of factors affect the rate at which maize hybrids mature including the planting date, soil type and fertility but the most important influence is the accumulation of heat. 

Pioneer uses the Comparative Relative Maturity (CRM) system to indicate the amount of heat that each Pioneer® brand maize hybrid requires to reach the ideal silage harvest drymatter (30 - 38% whole plant drymatter). In the Pioneer maize hybrid nomenclature system, the second digit gives an indication of hybrid maturity with hybrids with lower numbers requiring less heat to reach maturity than those with higher numbers. A Pioneer® brand hybrid with a silage CRM of 94 (e.g. Pioneer® brand P9400) will require less heat to reach maturity than a Pioneer® brand silage hybrid with a silage CRM of 107 (e.g. P0891). Note that the CRM is not the number of calendar days from planting to harvest.

Hybrids with low CRM ratings are more suitable for cooler areas, if planting is delayed or if an early harvest is required. These hybrids have a lower yield potential. Hybrids with high CRM ratings have a higher yield potential but they require more heat to reach silage maturity. These hybrids are best adapted to warmer regions where planting is early and a mid to late autumn harvest date is targeted. Ensure that the maize hybrid that you choose is the right maturity for your growing area. If the relative maturity is too long, harvesting and re-grassing will be delayed and grain content (and therefore silage quantity and quality) may be reduced. Conversely, if the relative maturity is too short yield potential will be reduced.

To select the Pioneer® brand maize silage hybrids that are the right maturity for you …

  1. Determine the target planting date. Consider when the paddock can be released from the grazing round and how long it will take to complete any drainage and contouring as well as cultivation time.
  1. Determine the ideal harvest date. Paddocks should be harvested early enough to enable pasture or a crop to be established prior to the winter. Allow time to complete groundwork or perennial weed control before regrassing. If you want to feed maize silage in the autumn and you have no carry-over supplies, consider when you will need the feed. Remember that the actual harvest date will vary as outlined above.
  1. Consult your maize silage contractor. It is impossible for all maize crops in a district to be planted or harvested at the same time. Discuss your proposed cropping program with your maize silage contractor to determine how it fits in with his work schedule.
  1. Use the latest Pioneer® brand Maize for Silage catalogue. The hybrid selection guide in this booklet will help you determine the hybrid maturity range that is most suitable for you. For further information, call Pioneer toll-free on 0800 PIONEER (746 633).

SOUND AGRONOMICS

Pioneer® brand maize hybrids have been selected for sound agronomic performance including drought tolerance, standability, early growth, and disease resistance.

Early growth, drought tolerance, staygreen and standability are probably the most important agronomic criteria to consider when choosing a maize silage hybrid. If specific diseases have been an issue in previous crops, or are a problem in your area, choose a hybrid that has good resistance ratings for those diseases.

Early growth is a measure of the speed at which young maize plants grow. This is important in cooler seasons, heavy soils or for very early planting.

Maize has a deep fibrous root system that enables it to efficiently utilise sub surface water. Its canopy effectively channels dew and rainfall to the roots. For this reason all maize plants exhibit excellent drought tolerance when compared to shallow rooted crops or pastures. However, some hybrids have been bred specifically for a high drought tolerance and these should be considered especially when planting in light soils in low rainfall areas.

Staygreen is a measure of the late season plant health. This is an important silage trait because it prevents a rapid increase in whole plant drymatter near maturity providing a “wider window of opportunity” for harvesting at the correct silage drymatter content. A high staygreen rating is less important if your crop will be harvested either very early or very late in the season since contractor availability is likely to be greater. It is also less critical if you have your own harvesting equipment.

Finally standability should be considered. Look for root and stalk lodging ratings of 5 or greater when planting maize silage crops in exposed paddocks in coastal or high wind-run areas.

TOTAL DRYMATTER YIELD

From those hybrids that meet your maturity and agronomic requirements, choose three or four that will give you the highest total drymatter yield. Hybrid selection decisions should be based on maize silage summary data. At least 20 side-by-side comparisons are required to ensure that the hybrid yield or nutritional differences are due to genetic differences and not environmental causes, maturity differences or sampling errors.

NUTRITIONAL QUALITY

The final consideration should be maize silage quality. The highest quality maize silage hybrid will be the one providing the highest milk output when fed in conjunction with pasture. Modelling through the Cornell Net Carbohydrate and Protein System model showed that in New Zealand, differences in hybrid quality accounted for $34/t maize silage DM in extra milk income whereas differences in hybrid yield accounted for $8,672/ha of maize grown (Kolver et al, 2003).

Initial indications suggest that the level of non-structural carbohydrates (sugar and starch) has the most nutritional impact on the milk production potential of maize silage hybrids. It is no surprise that these readily available energy components have a large impact since maize grain supplies 80% more energy than stover on a kilogram for kilogram basis.

Further research is necessary to clearly define maize silage quality for a range of different pastures and maize silage feeding rates.

CHOOSING A PIONEER® BRAND MAIZE SILAGE HYBRID

Pioneer constantly strives to breed maize hybrids that produce the highest yields of high energy silage per hectare. Remember comparisons can only be made between hybrids within +/‑ 4 CRM range. A silage CRM 77 hybrid with a silage yield for maturity rating of 9 WILL NOT yield more than a 87 silage CRM hybrid with a silage yield for maturity rating of 7.

For specific advice on the best maize silage hybrids for your farm contact your local Pioneer representative.



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The information in this publication is general in nature only. Although the information in this publication is believed to be accurate, no liability (whether as a result of negligence or otherwise) is accepted for any loss of any kind that may arise from actions based on the contents of this publication.

© 2017, Genetic Technologies Limited. No part of this publication can be reproduced without prior written consent from Genetic Technologies Limited.

Revised: June 2015
Expires: June 2017