New pond prevents boggy soils

Logan Bowler and Kathy Craw held an open day as their new effluent pond was lined. Photo / Laurel Stowell

The effluent pond installed on a Marton dairy unit last week has been a high priority for the pair who bought the farm 3 years ago.

Headed up "Crap Day Out", Logan Bowler and Kathy Craw held an open day on January 13, to allow other farmers to watch the installation.

Education is important to both of them.

Mr Bowler is from Marton and works fulltime as DairyNZ's North Island environmental extension specialist. Ms Craw was brought up on a dairy farm at Taikorea in Manawatu.

She has sharemilked and managed dairy farms, as well as worked as a Horizons Regional Council rural adviser for 2 years.

The new pond will hold 2000 cubic metres of effluent and prevent them irrigating effluent on to wet soils.

"We don't want to irrigate wet soils. When it's really wet around here the last thing you want to do is to put more liquid on," Ms Craw said.

Bigger sump

When the two got together, they wanted to buy land. They scraped together all their savings to buy the 96ha dairy farm on the outskirts of Marton.

At the time it was storing dairy shed effluent in a small sump, and irrigating it to land daily.

They immediately spent about $85,000 on a larger sump - but it still meant daily irrigation.

With the new pond they can store effluent until the soil is dry enough to absorb it.

"That's going to be one of the huge things for Kath, not chasing an irrigator when calving. Spring is the worst time," Mr Bowler said.

"It's wet, the cows are making more effluent and being milked. Now we will just open a valve and fill the pond. It's so much easier."

The new pond is costing $70,000 to $80,000. The two can afford it now that dairy prices have improved.

"For this little farm, the effluent system is costing close to $200,000. It's a lot of money but it gives us a licence to carry on."

Their herd of 220 eats mainly ryegrass and clover pasture, plus some hay and baleage the pair make themselves and some silage, hay and palm kernel expeller that they buy.

They use an "average" amount of fertiliser, as well as irrigating with liquid effluent.

They also spread solid waste once a year, in early autumn. Some of it is mixed with wood chip from their wintering house and some is from their feedpad and stored in a bunker.

The feedpad is concrete, and cows feed on it for parts of each day in the wettest two months of the year. They sleep in the wintering house for about a month of cold nights.

Contractors make last minute adjustments to the new effluent pond. Photo / Laurel Stowell

"It's a dry place to sit. It's not perfect but it's better than being in a wet, muddy paddock," Ms Craw said.

With a $4/kg milksolids payout, the farm could just break even and pay interest on debt.

With a $6 payout predicted this year, the two plan to put some money into improving their cattle races.

It was too windy on Friday for contractors to line the new pond with the black high density polyethylene plastic they had on hand. About 20 people came to the open day, including farmers, milk companies and regional council staff.

The lining was finally put in place the next day.

Under it are strips of gravel covering drains, to capture any effluent that leaks through.

The fluid drains into a sump with a manhole that can be lifted to check for leakage.

Also under the lining are vents to stop any gas in the soil making bubbles under the lining.

Immediately under the plastic lining is a geotextile fabric, to protect it from being punctured.

The linings have a manufacturer's guarantee for 20 years. But IS Dam Lining technical sales engineer Brook Newson says they have been known to last for 50.

Contractors will also install two ladders into the pond, so that anyone who falls in can get out.

Blackley Construction contract manager James Christensen once went back to see a pond they had made. It was full and they found a woman swimming around in it.

She was trying to catch her dog, which had fallen in, and she used a ladder to get out.

In a nutshell:

• Kagan Ltd Farm, Nga Tawa Rd, outside Marton
• 96ha, flat
• heavy clay soil
• herd of 220 dairy cows
• mostly grass fed
• feedpad and wintering house
• produces 80,000 to 85,000kgs milk solids/year
• supplies Open Country Dairy