Building sand country into a dairy farm has been rewarding for Bruce Cave. Photo
After some smelly problems, Bruce and Annette Cave have turned their coastal Wanganui sand country into a highly productive dairying enterprise.
The Caves showed off their achievement to a group of about 15 last week, in a visit arranged by the Wanganui Rural Community Board.
Three district councillors, three regional councillors, two Federated Farmers office holders and two MPs met them at their Seafield Rd milking shed on a windy afternoon.
Rural board member Tex Matthews began by saying the Caves had converted what was not a lot more than sand dunes into something pretty highly productive - using local resources, ingenuity and a lot of water.
The couple started with a sheep and beef farm and low returns, added 250ha and converted to dairy 22 years ago. Their initial herd was 400 cows, milked in a 40-a-side herringbone shed. Now they have 570ha, half of it irrigated, and milk 1100 Friesians.
They have increased production on their coastal sand country from 3000kg dry matter/ha/year in poorer parts to 12,000 to 15,000kg. They employ 10 permanent staff and several casuals.
Their milk usually goes to Fonterra, but they are about to supply Open Country because their ability to buy new Fonterra shares can't keep pace with increased production.
This year they will produce 440,000 to 450,000kg of milk solids, and milk about 400 cows through winter. They're in their third season of milking in a new rotary platform shed.
Productivity improved when they scraped the thin layer of topsoil off the sand dunes, smoothed them out and then put back the topsoil with added organic matter and irrigation.
Affco asked whether they would use paunch waste from the Imlay meatworks as organic matter to build the soil. They decided to try and Affco paid for the resource consent.
"It was smelly downwind, but it made the grass grow like crazy and it looked fantastic," Mr Cave said.
But when they put cows into the first treated area the animals did a circuit and walked out again - possibly the grass had a taint of death. "They wouldn't eat it. We had to cut it for silage and they ate it then."
They tried poultry manure as organic matter, but that was also too smelly for their neighbours.
The most successful addition was sawdust and peeler bark, from a timber mill in nearby Manuka St. It was applied with added nitrogen, grass seed and irrigation.
One area was ready for sawdust to be applied when the mill went bankrupt. It was irrigated anyway, but took a lot longer to build up fertility.
Then for a while the Caves used green waste from a transfer station as their organic matter. That also needed resource consent and the waste tended to come with other rubbish. That source has now dried up as well.
Ten years ago the cost of all those fertility improvements was about $3000 for 0.4ha.
The farm has a two-pond system for dairy effluent, and liquid and solid effluent are added to the soil. They improve fertility and reduce fertiliser bills.
Horizons Regional Council staff were initially worried about nutrient leaching from dairy farms on sand, but Mr Cave said that concern had lessened, compared with other soils.
"In our situation, because we are close to the sea, any potential leaching from our place wouldn't go into freshwater."
The couple get their farm water from bores 40m to 280m deep. Finding water in the sand country was easy, but could be expensive.
The overall result of changes to their land use may be the development of a deeper topsoil.
That was contrary to the expectation of AgResearch scientist Dr Alec Mackay, but Mr Cave said that was what he would expect from uneaten dry matter and cow manure adding to the soil.
The couple have looked for grasses that are productive under irrigation. Kikuyu was useful on unirrigated dunes, but they preferred to grow more nutritious grasses under irrigation.
They also grow barley and turnips to feed the cows, and give them 1-2kg of palm kernel every day, especially when they've been grazing the poorer pasture.
"With dairy cows, the key is to feed them well every day."
Mr Cave has no regrets about changing the former dune landscape to the contrasting bright green of dairy pasture.
"For me, as farmer, seeing gently contoured, irrigated productive pasture - I would rather see that than windblown sand."