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
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
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