Dryland techniques can help cropping farmers

Cropping farmers with storm-damaged irrigators may need to adopt dryland farming techniques to maintain production until repairs are complete and water restored, the Foundation for Arable Research (Far) says.

Last month, more than 800 irrigators throughout the region were damaged by strong winds putting pressure on installers to complete repairs ahead of the irrigation season.

Far Cereals research manager Rob Craigie said while some Canterbury cropping farmers had only recently moved to irrigation and were familiar with dryland practice, others had been under irrigation ''for years''.

''This has come totally out of left field ... it's something people would never have considered.''

He said two factors should be uppermost in minds of arable farmers waiting for repairs.

Nitrogen application - the input which had the biggest impact on crop yield - was ''constrained'' by lack of water.

And disease management would need to be altered if conditions became dry, he said.

The crop canopy would not be as dense as it might be under water and there would be less chance of fungal disease so fungicide applications would need adjusting.

However, if spring conditions matched those of the past two years, the effect of lack of irrigation on yields might not be too significant, he said.

''The last two seasons, it hasn't been dry until December so it hasn't been yield limiting.

''But irrigation has taken away that certainty,'' Mr Craigie said.

Far has issued general advice to arable farmers and recommended they seriously consider some dryland crop management approaches, at least in the short term.

In particular, regarding the timing and overall rate of N application.

It recommends timing an application to just before, or even during, rainfall to help reduce N loss to the atmosphere.

Applications could be delayed if there was a good soil mineral nitrogen reserve.

However, where repairs were expected to take longer and turn some crops from irrigated to dryland, it was important to review the agronomy of the whole crop, including the overall rate of N application, Far said.

For further information, visit the Foundation for Arable Research website www.far.org.nz.

- by Ruth Grundy 

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