Maize for Silage
Insight 301


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Successful establishment of a maize crop relies upon following all the recommended steps at the correct time. If possible, select your paddock in the early autumn. Walk the whole area and check for the following:


If perennial weeds are not controlled they can cause a significant reduction in maize yield. If weeds are present in small areas, spot spray immediately to reduce the risk of weeds being spread during cultivation. Autumn control is more effective since the plant is actively growing. If the total area is infested with perennial weeds, spray out the whole paddock and plant a winter crop such as greenfeed oats or Italian ryegrass.


Maize does not perform well in waterlogged soils. Waterlogging can also encourage weeds like willow weed to invade the crop. This can reduce maize yield and also impact on silage quality, palatability and stock health. Drain any areas where water ponds to allow earlier cultivation, better weed control and reduction in nutrient leaching.


Always soil test to determine the most suitable fertiliser and lime input. Fertiliser requirements will vary greatly depending on the history and fertility status of the paddock. 

High fertility long-term dairy pastures including those which have had a history of effluent application may require no fertiliser while continually cropped paddocks or run-out sheep and beef farm pastures sometimes require capital fertiliser applications. Always soil test and do not apply more nutrients that you need.

Soil core to the depth of cultivation - normally 150 mm and up to 300 mm on peat soils. Lime requirement is increased in areas where contour correction is required especially on heavy soils and peats.


It is important to choose the correct Pioneer® brand maize hybrid for your area and farming system. See the latest Pioneer® Maize for Silage catalogue and contact your local Pioneer Representative for hybrid advice. Some important factors to consider are:

  1. Comparative relative maturity (CRM). This is an indication of the growing period from planting to harvest. The actual crop growing period will vary according to the amount of heat the crop receives (i.e. spring, summer and autumn temperatures) during the season. The warmer the season, the shorter the period from planting to harvest. See the Pioneer® Maize Silage catalogue for average planting and harvest dates for Pioneer hybrids in your area. Note: The "comparative relative maturity" of the hybrid is not the number of "calendar days" from planting to harvest.
  1. High total DM and grain yield. Hybrids must have a high total drymatter yield as well as a high grain yield to achieve maximum metabolisable energy yield per hectare. Grain yield is important as grain contains 70% more metabolisable energy and greater carbohydrate levels than stover (the green part of a maize plant).
  1. High population adaptability. High plant populations are necessary to ensure high silage yields. All Pioneer® brand maize hybrids have been fully tested for their adaptability to high populations and fulfil this requirement.
  1. Drought tolerance. If planting into paddocks with drought prone soils choose a maize hybrid with a good drought tolerance rating.

Staygreen. This is a measure of late season plant health. Hybrids with good staygreen ratings will have a wider “window” for silage harvest. This allows for harvest delays due to weather, machinery breakdown or contractor hold-ups. 

establishing a maize silage crop

Spray out pasture

Spraying out pasture reduces the number of cultivation passes required to achieve a desirable seed bed. It also eliminates pasture re-growth and reduces turf clods on the seed bed surface. This in turn enhances the performance of chemicals for weed control.

Spray out pasture as soon the paddock can be taken out of the grazing rotation. Spraying out 3 - 6 weeks prior to planting date is ideal as it gives plenty of time to create a good seed bed, however many farmers spray out 1 - 3 weeks prior to planting. Avoid leaving waste weedy areas around the paddock edges as insect infestations can start in these areas and spread into the crop.

Chemicals for pasture desiccation: Round-up Renew (glyphosate).

Contour and lime

If contouring is not required apply lime as soon as vegetation has started to change colour after the desiccant herbicide spraying. If contouring is required, undertake cultivation and apply lime when shaping is completed. Apply extra lime where drain banks or humps have been removed, especially on peat or clay soils.

Base fertiliser

Spread and incorporate the base fertiliser dressing. For "run-out" peat pasture include Sulphate of Ammonia with the base dressing to assist root clod breakdown and offset nitrogen deficiency. Allow 7 - 10 days between applying the base fertiliser and planting to reduce the chance of fertiliser burn damaging the seed or seedling roots. This is especially important in free draining soils and dry immature peat soils.

Cultivate seed bed

A well-prepared seed bed enables weed control chemicals and insecticides to give optimum results, enhances crop establishment and allows planting machinery to function more accurately. Do not over-cultivate.

Final cultivation

If more than 24 hours have elapsed or it has rained since the last pass of the cultivator, make a further pass with a surface cultivator (e.g. rotor-tiller), before planting. 


Maize hybrids for silage must be precision planted. Choose a competent contractor with well-maintained machinery. Have the insecticide treated seed and starter fertiliser on hand for his arrival.  Planting can commence once the 9am soil temperature reaches 10°C at a depth of 50 mm and is rising when measured over three consecutive days.

Starter fertiliser

Starter fertiliser is a mixture of N-P or N-P-K formula fertiliser. Out of pasture on lighter loam and ash soils, an N-P selection is normally chosen. On peats an N-P-K blend is sometimes chosen if the potash requirement was not met with the base fertiliser application. The starter fertiliser is applied through the planter at rates normally in the 125 - 375 kg/ha range. The rate of fertiliser you apply should be determined using your soil test result and taking into consideration a realistic yield target.

Starter fertilisers: Di-ammonium Phosphate (DAP) 18-20-0, or 12-10-10, also many other formulations.


Seed is a living organism.  Store it in a cool, dry place prior to planting and handle with care. Avoid throwing bags. Cracked and damaged seed is more vulnerable to microbial and fungal infections once planted.  Plant Pioneer® brand maize silage hybrids at the recommended rate (as per the current Pioneer Maize Silage catalogue).

Insect control

Quality seed treatment maximises crop yield and protects growers’ maize seed investment.

Weed control

Weeds fall into two main categories - grass weeds and broad leaf weeds. Some sprays control mainly grass weeds, others only broad leaf weeds and a third group give control of both. Time of application varies depending on the chemical and the weed species present. The best weed control option will vary from farm to farm depending on the soil type and the number and species of weeds present. Plan pre and or post planting herbicide applications based on specific weed problems by paddock.

Pre-emergent herbicide (such as Roustabout) will be most effective if applied within 24 hours of planting.

The type of post-emergent weed control herbicide used is determined by the type of weeds present. Seek specialist advice from your merchant, chemical company representative or Pioneer Representative.


From about 6 days after planting check crop emergence. Full emergence normally occurs 7 to 14 days from planting depending on temperature. Continue to walk the crop, preferably daily, checking for insect and bird damage and weeds. 

  • Argentine Stem Weevil. Plants that have been damaged by the Argentine Stem Weevil (ASW) turn a blue-grey colour, the inside leaves wilt, and then the plant dies. There is no known spray to control ASW in seedling maize. Significant seedling damage is uncommon where insecticide treated seed has been planted.
  • Greasy Cutworm. The symptoms of Greasy Cutworm in the crop are plants that have been cut off at ground level. Greasy Cutworm is a dark coloured caterpillar that feeds at night and burrows down into the soil during the day. It is easily located in the early morning and if significant numbers of the plants are affected an urgent spray programme is required. Consult an insecticide company representative for assistance.
  • Bird damage. If you find small seedling plants pulled out of the ground with the roots still attached, it is probably bird damage. Birds can be attracted to the area by seed left on the surface of the ground when the planter lifts at the end of each planter run or on tightly turned corners. If you note seed on the ground at planting, draw your contractor's attention to the problem. If ducks are a problem and soil temperature is 14°C or higher, adjust the planting depth to 65 mm. Poncho® Plus seed treatment will help to repel birds from planted maize seed.
  • Seedling weeds. Contact the field staff of your local merchant or chemical company if you see weed seedlings in your crop. Control steps can be taken to keep the crop clear of weeds and maximise crop yield. Satisfactory weed control can only be achieved if crops are sprayed prior to row cover.


To determine whether your crop requires additional post-plant applied nitrogen take deep N sample (60cm) and use Amaize N fertiliser forecaster (available from your local fertiliser representative) to help interpret the results.

Sidedressing usually occurs 6 weeks post planting or just prior to row cover. Urea is the most commonly used nitrogen product for sidedressing although calcium ammonium nitrate (CAN) is a worthy alternative. Methods of application range from broadcasting the urea just prior to rain to specific machines that knife the urea into the soil between the rows. There are also combination knives that apply nitrogen to the ground and inter-row mould covering the nitrogen in the process.

Please note:  There are a wide number of herbicides and fertilisers available. Some of the herbicides and fertilisers that can be used are listed in the text above. This list is not complete and no particular preference is indicated by the inclusion (or omission) of herbicides.

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1Trial data supplied by Bayer CropScience

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Revised: Sep 2019
Expires: Sep 2022