Just add water, project shows

Just add water. That's the key to the successful crops that have been produced on the two Kaipara Water demonstration sites this season.

The highly fertile ground has responded well to the two types of irrigation treatments being tested.

The result has been bumper crops of juicy watermelons, kamokamo, beetroot and soybean/edamame that have been distributed throughout the community in food parcels compiled by Dargaville Combined Churches Food Bank, Mauri Ora ki Ngati Whatua Charitable Trust services, Otamatea Community Services and Mangawhai's Te Whai Community Trust. Some produce had also been dropped off at pataka kai (community pantries) around the district.

Kaipara Water project manager Curt Martin, of Kaipara District Council, said the team was happy with the first season's results and the knowledge that had been gained.

Sharing the produce added to the benefits of having the demonstration sites.

"It's fantastic that local community services have been able to distribute the demonstration produce from this season, an additional yet important contribution from the project to the Kaipara community," he said.

Martin said the crops had been chosen to demonstrate smart water use, "with the potential to inspire and support land diversification in the district".

Learnings from the seasons would be made available on the Kaipara District Council website.

Site manager Greg Hall, of Northland Inc, said the sites faced challenges and lessons learned that would be shared with landowners wanting to try similar enterprises.

"The quality of the produce has been really good and we're almost sick of watermelons," he said.

Hall said planting crops on farmland fresh out of pasture meant weeds had been a problem on the sites.

"For optimum crop results on farmland fresh out of pasture, weed suppression needs to start in the preceding autumn. A cover crop should ideally be planted on sites through the winter.

"Unusually wet conditions at the end of last year combined with the lack of a cover crop pre-planting have been the key contributions to the significant weed pressure seen on both sites," he said.

Nightshade and tobacco weeds had popped up once seeds were exposed during planting.

The soybean crops had been affected, not achieving the expected height, but they did produce a lot of pods.

The sites would be planted in a cover crop for winter before next year's crops were planted in the spring.

"Next year we should see a vast improvement," he said.

Northland Inc is contracted by the Kaipara District Council to manage the two sites, at Te Kopuru on private land, and north at Maunganui Bluff on iwi land.

Site 1 at Maunganui Bluff has an in-ground irrigation system that is set to water in precise amounts every two days. Te Roroa iwi members had been harvesting kamokamo and watermelon.

The yams struggled due to early irrigation issues and higher-than-expected soil temperatures in January and February. No yam plants survived.

Site 2 at Te Kopuru is watered weekly using a centre pivot irrigator and crops have been harvested since the start of March, with good numbers of large watermelons and beetroot. The soybean/edamame plants were stunted due to pressure from weeds and the kaanga ma (Maori corn) had also had slower growth.

Hall said there was a balancing act to manage pest insects alongside the withholding periods of sprays prior to harvesting.

"Until last month we noted there had been no major pests at either of the sites. We continue to battle significant weeds and, unfortunately, we have also seen army worm get into the beetroot and the sweetcorn on both sites, something that can only be combated by high-cost aerial spraying (for the corn), which is not feasible for the size of the sites. Some errant cows also managed to navigate stock fencing that had been put in place, so greater measures are needed to keep them out."

Hall said the project was being well supported by horticulture specialists, researchers and seed experts.

"We have found that the pivot irrigation system is easy to run once it is installed. You can just programme it and let it go.

"The drip tape system at Site 1 is very labour intensive to set up and remove each time machinery needs to be used on the site. However, the drip tape allows water to be better targeted where it is needed."

The sites have had visitors over the past few weeks, including landowners and farmers, iwi and community group representatives, all looking to learn more about the irrigation techniques being demonstrated and opportunities for land diversification in Kaipara.

The Kaipara Water demonstration sites are part of Kaipara KickStart, led by Kaipara District Council and supported by the Government's Kanoa - Regional Economic Development & Investment Unit, with funding from the Provincial Growth Fund.