Maize for Silage
Insight 345


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A Forage Production Unit (FPU) is a block of land that is used to produce forages (maize and a winter crop) for contract sale or for a farmer’s own use. FPUs provide an excellent level of return and are an excellent option for:

  • Farmers who wish to exit dairying but retain their land.
  • Dairy farmers who want to secure cost-effective feed that can be harvested and carted to the milking platform.

 This technical bulletin will discuss FPUs, the likely financial returns, management input and sustainability.


As well as delivering an attractive income, an FPU provides lifestyle benefits when compared to milking cows. Almost all of the work is done by a local agricultural contractor leaving you more time to pursue off farm interests.

Farmers can choose to stay on the land rather than moving into town when they wish to retire from milking. Not all farmers enjoy finding and managing staff. In most cases an FPU can be run without the need for additional labour.

By retaining the land, you continue to reap the benefits of capital gain and it can be sold down the track if you choose to move into town or kept in the family long-term.


For most farmers the change to an FPU starts with the sale of stock, shares and sometimes plant and machinery. The amount of the farm planted in crops varies depending on contour and soil type.  Steeper contours are used for grazing and some of the more fragile soils need to be rotated to ensure they remain healthy and therefore cropable.

Maize silage is the crop of choice for Forage Production Units. This is because it has the highest yield potential of any commercially grown crop in New Zealand. A deep rooting structure and excellent drought and disease resistance means that yields are relatively stable year after year. Quality is consistently good and there is a stable on-going market for maize silage for sale into the New Zealand dairy industry.

The FPU generates three streams of income:

  • Capital investment income from the investment of the money generated through the sale of stock and Fonterra shares.
  • Cropping income from the sale of maize silage and a winter crop (e.g. Italian ryegrass) which is grown over the winter months between maize silage crops.
  • Heifer grazing income generated from the area of the farm that is not under crop.


In this example a 70 ha Waikato dairy farm milking 210 cows and producing 77,000 kgMS is converted to a Forage Production Unit.

Livestock values are 1:

  • Cows $1,600 per head
  • Heifers $1,200 per head
  • Rising 1 year olds (i.e. last year’s calves) $800 per head.

We assume Fonterra shares are sold for $6.10/kgMS1 and that the cash generated through the sale of stock and shares is invested at 3.5% per annum.

A total of 80% of the land is cropped in maize silage followed by Italian ryegrass. The maize silage yields 20 t DM/ha/year and the Italian ryegrass yields 4 t DM/ha/year. Both maize silage and Italian ryegrass are sold for 25 c/kgDM standing.

It is assumed that it costs $2,270 to grow a hectare of maize silage2 and $400 to grow a hectare of Italian ryegrass.

Heifers are grazed at 3 per hectare and the return is $9 per head per week.

Capital investment income

The capital investment income is as follows:

Capital investment income

The capital investment income is as follows:

Sale of cows (210 @ $1,600/head)


Sale of heifers (42 @ $1,200/head)


Sale of rising 1 year olds (42 @ $800/head)


Sale of Fonterra shares (77,000 @ $6.02/share)


Total capital to invest


Capital investment income @ 4.5%


Cropping income

The cropping income is as follows:

Maize silage income (20,000 kgDM @ 25 c/kgDM)


Grass silage income (4,000 kgDM @ 25 c/kgDM)


Total returns from sale of feed


Maize silage growing costs2


Italian ryegrass growing costs


Total cost of growing forages


Farm profit from cropping


Heifer grazing income

The heifer grazing income is as follows:

Heifer grazing charge ($/head/week)


Number of heifers grazed


Total returns from heifer grazing


Total income

The total income for this operation is: 

Capital investment income @ 3.55%


Farm profit from cropping


Total returns from heifer grazing


Total return from Forage Production Unit


Gross margin per hectare ($)


1 October 2017
2 Pioneer® Brand Maize Silage 2017-2018 catalogue


The benefit of this FPU system is that there are three streams of income. The income generated from forage (maize plus standing grass) sales is the largest and represents around 70% of the total return. The impact of changes in maize silage yield and selling price on the gross margin per hectare from the FPU is shown in the table below.

Maize price

 Maize silage yield (tDM/ha)    

























As you can see, overall farm income is good over a range of maize silage yields and selling prices. There are a number of expenses that must be deducted from this gross margin analysis. They include:

  • Capital and interest repayments on the land.
  • Depreciation.
  • Power, rates and insurances.
  • Wages and/or personal drawings.


One of the big advantages an FPU is that it requires a relatively low level of time input and expertise to manage. All of the cropping operations from spraying and cultivating through to harvesting can be done by a local contractor. Cropping management input is limited to coordination of the contracting activities and crop walks especially during the early part of the season.

The heifer grazing may require some time input for moving stock although that will depend upon the individual grazing contract.


On many soils throughout New Zealand, a “maize in summer, annual ryegrass in winter” cropping rotation has proven to be very sustainable.  However, on more fragile soils, the percentage of the farm that is kept in permanent pasture to increase long term sustainability from a soil perspective will need to be determined on a farm by farm basis. For some farms the cropping land can be used as a nutrient sink for local dairy farm effluent reducing the fertiliser requirements and holding or increasing soil organic matter levels.  This is especially true for cropping units located close to an effluent source such as a chicken farm or a dairy cow barn.


There are a number of other options for farmers wishing to investigate maize cropping. These include:

  • Leasing land to a local contractor who will grow and sell crops and manage the entire operation.
  • Growing maize for grain for sale to a local drier. Currently, the demand for maize grain is high and it is an excellent option particularly for farmers who do not have a dairy market for wet forages in close proximity to them.


Pioneer® brand products have developed a comprehensive spreadsheet that will help you to analyse the potential returns from an FPU on your farm. 

Contact your local Pioneer representative to arrange a free, no-obligation visit.

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.

© 2021, 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