Maize:
For maize, cost of inputs will be around $2,000/ha to grow and harvest the crop as silage, with labour and feeding out costs to be added. If you decide to plant maize for silage, don’t cut corners.
Good weed and African Black Beetle control are essential, as is ridging on flood-irrigated land. Maize is a high-input crop and you need to be prepared to spend the time and money necessary to allow it to realise its potential.
Dryland:
Light cultivation will help conserve soil moisture and assist establishment. Dryland crops are generally seeded at about half the seeding rate of irrigated crops. They need to receive their fertiliser at seeding and a nitrogen/phosphorus fertiliser should be used. DAP or Agras at about 300 kg/ha have given good results.
They are relatively inexpensive to establish. Seed (10 kg/ha @ $4.50 /kg) and fertiliser (300 kg/ha @ $350/t) costs will be about $150/ha, with cultivation and seeding costs on top.
Some trial results:
A comprehensive evaluation of forage crops under almost ideal conditions at Harvey back in the 1980s produced high yields of generally low quality forage. Some varieties have changed since then but others are still being used. The table below shows typical yields and quality for the different crop types in this trial.
The sweet sorghums were allowed to grow right through summer to be cut for silage while the others provided two or three grazings. In this trial, maize yielded about 40 t/ha dry matter but a recent more commercial crop at Wokalup yielded about 22 t/ha and this was considered a very good crop.
Suggested budget for a maize crop/ha
Farmer experience:
A crop of Nutrifeed (Pearl Millet) grown under sprinkler irrigation at Boyanup produced just over 14 t/ha dry matter over summer, of which about 11 t/ha was utilised. The paddock was cut for hay, cultivated and the crop planted just before Christmas.
It was grazed three times between January and March. Energy remained at about 11 MJ/kg DM and crude protein at about 20% right through summer. A dryland crop of Jumbo planted at Boyanup in late November and sampled in late January yielded about 10 t/ha dry matter at 10 MJ/kg DM and 10% crude protein in the good bits.
The crop was very variable, with crop height ranging from 0.8 m up to 1.6 m. Dryland crops often produce only one good grazing, with the amount of regrowth depending on summer rain. In very dry summers, they can fail completely.
Where do they fit in?
Summer forage crops can produce useful feed over summer but you need to be sure that the cost is justified. On irrigation farms, a forage crop is generally the first crop planted after land forming.
Forage crops are easier to establish than pasture in summer, they generally handle hot weather better than pasture and they allow options for weed control before pasture is planted in autumn.
Staggered planting goes some way to preventing all the forage crop being ready for grazing at the same time but this can still be a problem. Don’t put the milkers into an over mature crop just to clean it up - use dry stock for this and keep the milkers on your highest quality feed.
If a dryland summer forage crop is being planted as part of a renovation program for deteriorated pasture, make sure you know why your pasture has deteriorated before you spend money on the crop.
Planting the crop after harvesting pasture for silage or hay means that you won’t be sacrificing spring pasture growth but you will need to reseed the pasture in autumn.
Be very careful with crops which have the potential to be toxic, especially if they become stressed through of lack of moisture after the first grazing. Summer/autumn rain will stimulate fresh growth which can be very toxic. Millets are the safest option.
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