Dual cropping ‘Ts & Cs’

Answering your questions about dual-cropping maize with winter legume-based forages.

Dual cropping  ‘Ts & Cs’

The fact that dual cropping maize with winter legume-based forages results in two streams of income from one land in one year is an enticing prospect. But making significant changes to proven farming practices is always risky. I have no doubt that the risk, capital cost and effort are more than justified. But ‘terms and conditions’ apply! I trust that the following will answer some of my readers’ questions.

Biological farming
Grain producers must improve the biological fertility of their arable lands to reduce the amount of chemical fertiliser required in crop production. They have no choice in the matter – the fact that the price of fertiliser is very closely linked to the ever-spiralling cost of fossil fuel dictates that a change must take place.

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In Australia’s winter rainfall areas, it has been common practice for many years to build soil fertility with perennial legume-based pastures planted in rotation with winter grain crops. The pasture phase is normally six years, followed by four years of cash cropping. Tramline maize with winter legumes is an adaptation of the Australian system. And it works! A considerable reduction in the amount of nitrogen fertiliser required to produce a good maize crop can be achieved.

Maize yield
Tramline maize is best suited for lands that have a long-term yield potential of 4t to 7t grain/ha. A yield of less than 4t is unlikely to return a profit even at a good grain price. Above 7t, the chance of reaping less grain from tramlines, as opposed to conventionally spaced maize, increases. A drop in the maize price will, of course, swing the economics in favour of dual cropping with tramlines. Seen from another angle, dual cropping stabilises profits in the long run. What’s more, the high-quality forage grown in the pathways that separate the tramlines can be converted into profit by animals.

The animal factor
The type of animal allowed to use the winter pastures planted in the pathways between the maize tramlines will determine how much profit is made. Animals must be regarded as ‘cash converters’ – in other words, they must convert the stover/legume forage into cash. Traditionally, maize stover has been used as an inexpensive way of overwintering livestock, but when winter legumes are added, the scenario changes from overwintering to production.

Sheep are the best cash converters. The tramline/legume combination will more than double the number of ewes and lambs that can be carried per hectare. The lamb growth rate will be higher and the effective grazing period will be extended, especially in years when winter and early spring rains are experienced.

Another good option is to use the winter forage for autumn beef weaners and then sell them in spring when prices are normally better. You can bargain on an average weight gain of at least 800g/day when they are on the upgraded stover.
Gestating cows are another good option. Dual cropping will ensure they are in good condition when they calve down in late winter and early spring, an important factor in determining their ability to reconceive.

John Fair, an expert on pastures, heads up Fair’s Biofarm Assist. He can be contacted on 058 622 3585 or [email protected].