Maize for Silage
Insight 336


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Hybrid maize seed can be planted once the 9am soil temperature is 10°C at a depth of 50 mm and rising when measured over three consecutive days or is at 12°C and static. This occurs in late September – early October in the Waikato/South Auckland areas.  There are a range of maize hybrids and they differ in the amount of heat (and therefore the number of calendar days) required to reach silage or grain harvest point.  Generally, the longer the hybrid maturity (or the higher the CRM) the greater the yield potential.

 Very short maturity maize silage hybrids (such as Pioneer® brand P9400 will take around 129 - 143 days from planting to harvest and yield around 18 - 20 tonnes of drymatter per hectare (tDM/ha) while longer maturity hybrids such as Pioneer® brand P1253 will take approximately 143 - 156 days from planting to harvest and yield 22 - 24 tDM/ha. Yields and approximate days from planting to harvest are for North and Central Waikato.

 Typically maize grain crops are harvested from late April onwards although there are several very short maturity maize grain hybrids (e.g. Pioneer® brand P8805) that can be harvested as early as mid-March.  Typically mid-full season maize grain hybrids will yield 11 - 14 tonnes of dry (14%) grain per hectare whilst early hybrids will yield 10 - 12 tonnes dry (14%) per hectare.

 Maize yields are remarkably consistent from season to season.  There are very few significant maize diseases in New Zealand and there is a wide range of herbicides and insecticides registered for use on maize.  In addition maize has excellent drought tolerance allowing for good yield accumulation even under dry conditions.


The maize grain price is usually set around crop planting time.  Grain companies will contract crops and sometimes provide finance for crop inputs. Maize grain is purchased on dry (14%) yield with the seller paying for harvesting, cartage and drying as well as crop establishment costs.

 The increased use of maize silage in New Zealand dairy farm systems has led to the development of a considerable market for maize silage. Typically crops are contracted to dairy farmers prior to planting with the purchaser paying a deposit with the balance being due at harvest time. Crops are generally sold on a “standing” basis with the purchaser paying for harvesting and all subsequent costs.

 The returns for maize silage and grain depend largely on the yield and the contract price.

 For more information on crop growing costs, see the latest Pioneer® Brand Maize for Grain and Pioneer® brand Maize Silage catalogues.  Your local merchant or maize contractor will be able to give you an indication of maize silage and maize grain sale prices.

Benefits of using maize within a vegetable rotation

As well as providing good financial returns, maize offers a number of other benefits including:

Improved soil organic matter levels

Maize grain and silage have a large root mass that returns considerable organic matter to the soil.  For maize grain, the entire plant is shredded and returned to the paddock as the grain is harvested.

 Reduction in weed pressure

There are many herbicides that are registered for use on maize crops thereby reducing the weed and volunteer potatoes pressure in subsequent vegetable crops. Most maize herbicides have short residual periods and thus allowing establishment of vegetable crops immediately after maize harvest.

 Reduced insect, disease and nematode pressure

Maize grain and maize silage offer a significant break in the lifecycle of many common vegetable pests and diseases including onion thrips, potato tuber moth, white rot and Sclerotinia.  Planting maize can reduce the insect, disease and nematode pressure on subsequent vegetable.

 Increased nutrient availability

Maize roots deeply into lower soil horizons lifting subsoil nutrients that can then be used for subsequent vegetable crops.


Maize grain and maize silage both offer advantages to vegetable growers.  The key advantages of each crop are outlined below.

Maize silage

  • Less trash for subsequent seedbed preparation.
  • February to April harvest time (depending on hybrid and planting date) allows timely establishment of vegetable crops e.g. onions.

 Maize grain

  • Lower organic matter removal than maize silage since the entire stover portion (stem plus leaf) is returned to the soil.
  • Short maturity grain hybrids can be early planted to allow harvest of maize grain in March/April.

    Pioneer® brand maize hybrids grown for either grain or silage provide an economic break crop option for vegetable growers. The advantages of growing maize are outlined in this technical bulletin.

Pioneer® brand products are provided subject to the terms and conditions of purchasing, which are part of the labeling and purchase documents.

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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.

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Revised: June 2016
Expires: June 2017