Fixed-grid irrigation under development

A Timaru man who has developed fixed-grid irrigation believes he has an answer for many irrigation issues on New Zealand farms.

Fixed Grid Irrigation Ltd manager Owen Batt says he believes his company is the only one in the country providing completely underground irrigation systems.

Also known as solid set irrigation, the system involved placing pop-up sprinklers inside a protective aluminium pod, which added strength so dairy cows could not damage the sprinklers and allowed tractors and other farm machinery to drive over it.

The system was completely underground except for when the sprinklers were running.

Although suitable for most kinds of farming, cropping farmers would not be able to utilise the system due to working the ground, and his company was targeting dairy farmers as its main market.

Mr Batt only knew of two farms which had similar systems.

Lower Waitaki Irrigation Company chairman and arable and dairy farmer Chris Dennison said he thought the system would have a place in the North Otago region, but uptake would depend upon the capital costs and economic restraints on farmers.

''If it still allows field operations such as mowing and so on, I think it will have a lot of merit,'' Mr Dennison said.

''I can see it being quite effective. It would have some uptake I think, working in with other methods [of irrigation].''

Mr Batt said the pipeline for the system would be laid in rows, with sprinklers laid out in a grid, mapped by GPS.

The company had been running for about 12 months and was still getting set up, he said.

So far, one demonstration block had been established, near Timaru, with much praise from the landowner.

A major issue with making fixed-grid irrigation a competitive irrigation option to centre-pivot irrigation was cost.

''I'm quite aware that at the end of the day to get it up and running it must be cost-effective and competing against centre pivots which are certainly the most cost-effective method of irrigation,'' Mr Batt said.

''It [cost] varies greatly per hectare, the simplest [irrigation system] is about $7000 per hectare through to about $12,000 per hectare. Fixed-grid is about $10,000 per hectare but I want to get the cost down so it is affordable for farmers. It boils down to how much someone wants to spend.''

His fixed-grid system had an 80% d.u (distribution uniformity) across the spray range from the sprinkler to the end of its reach, and could also take effluent.

Fixed-grid irrigation could apply any rate of water, as each sprinkler could be programmed to put out different amounts of water, depending on the soil moisture required. The technology used in the system had existed for years, before his company adapted it, he said.

Federated Farmers Southland dairy chairman Allan Baird said he did not expect such a system to be picked up by many Southland farmers, as although not cropping farmers, dairy farms still needed to cultivate their paddocks.

''I just wonder whether the infrastructure that is in the ground . . . and about the inability to cultivate or use those paddocks for winter cropping,'' Mr Baird said.

''There is places where that stuff will work but I have doubts whether it will be a seamless transition into dairy farming in Southland.''

While it would have appeal over K-Line for its ability to run effluent, it would need to be considered carefully, he said.

- by Leith Huffadine