Canterbury is a relative newcomer to the dairy revolution. Just two decades ago dairying was limited to town supply farms.
Now, it accounts for about 20 per cent of flat land farm use, thanks in part to the invasion from northern farmers seeking something that is in relatively short supply - flat arable land.
Canterbury has overtaken Taranaki in terms of the number of cows and is not far behind the Waikato.
In 1992-3 there were just 409 cow herds in Canterbury - 89,752 cows on 38,598ha producing 24.4 million kg of milksolids.
Last season, there were 1046 herds, or 826,325 cows, on 237,668ha producing 321 million kg of milksolids.
Over the same time span, the average herd size has grown from 219 to 790. Once sleepy towns like Ashburton are now growing, bolstered in no small part by the support services that dairying requires.
On a political level, Federated Farmers supports the broad thrust of the Canterbury Land & Water Regional Plan (LWRP) but has gone to the Court of Appeal to clarify some points.
The LWRP puts in place nutrient management rules that effectively halt land use change or intensification that may result in increases in nitrate leaching over large parts of Canterbury.
Dairying has been a key driver for the national economy. Last month, Westpac revised up its New Zealand GDP growth forecast for 2014 to 4.2 per cent from its previous forecast of 3.8 per cent, based in part on the strong performance in dairy.
On one hand, farmers are under pressure to produce more but also to tidy up their act environmentally.
Cow barns - which allow greater productivity while offering more environmental control - are seen as being one of many tools to get around the problem.
Cropping is big business in Canterbury and it's an added bonus for dairy farmers to have alternative feed sources on their back doorstep. For all farm types in Canterbury, water is the key.
Dairying has taken a lot of flak for the impact it has had on the country's waterways. Federated Farmers dairy chairman Willy Leferink says some of it has been warranted, some of it not. He says farmer attitudes have changed greatly, and for the better, over a short space of time.
To Leferink, who owns or has interests in six farms in the mid Canterbury region - good environmental practices go hand in hand with good business. "Any one kilogram of nitrogen than is lost [through run-off], is a lost opportunity because it could have been used to enhance growth," Leferink says.
"If you leach it, it does not enhance growth," he says.
Some, like Methven farmer Craige Mackenzie have taken on environmental responsibility with a missionary zeal.
He has championed the cause of precision agriculture - a land management concept based on observation and how to respond to variability in the land using new technology.
Mackenzie, who has just been appointed chairman of the Precision Agriculture Association, says farmers are waking up to good environmental practices, thanks in part to advances in technology such as GPS.
He says extensive analysis of the soil can be hugely beneficial to the farmer and the environment.
Soils built up over the ages can develop different characteristics, particularly when they are put to different uses.
If farmers are too heavy, too light, or too uneven in their use of phosphate, it can show up in soil samples years later. Mackenzie talks about the need for "sustainable intensification" in land use.
"Ultimately, we need to be able to produce more product with either the same, or less, inputs," he says. Mackenzie says there is often variability in the soil over quite small areas.
Using an example of a 15ha field on his own farm, an area of land that previously took 75 tonnes of phosphate now only requires 10 tonnes, thanks to detailed soil analysis.
"It's about putting the right product on at the right time and in the right manner," he said.
Mackenzie talks in similar terms about getting the right amount of water onto each part of the farm.
This involves mapping the soils to find out exactly what individual soil types require.
Over-irrigation promotes leaching, so it pays to get it just right, he says. On his own farm, variable rate irrigation saved about 30 per cent of the farm's water intake.
"Our yields are up and our inputs are down, so it's a good environmental story."
"Generally what is good for the environment is good for the bottom line," Mackenzie says. "We are sitting on the same bus alongside the Green Party because we have got the same philosophy."
Leferink has become involved in cow barns in mid-Canterbury, which he says can have positive environmental spinoffs. He has a share in a 960-cow farm near Ashburton that sports two huge barns.
He sees cow barns as "another tool in the toolbox" to allow greater productivity while providing greater control over nutrient run-off.
Cow barns are used extensively in Southland for wintering cows but cow barns as a way of increasing productivity are new to Canterbury.
Environmentally, the advantage is that effluent can be contained and treated on site. Waste water can be cleaned and reused for washing, and what's left spread back on the farm.
The cows spend just over half the year inside, and Leferink says they prefer to be inside at night.
The barns are open sided, with a high roof, and are not overly smelly.
Cow barns allow a more intensive form of dairying but Leferink does not expect their use to suddenly take off.
He says cow barns are particularly useful during winter because they allow farmers to save pasture for the spring. Financially, he says the numbers stack up well in times when the milk payout is high.
They come at a hefty price - about $8 million to $10 million in the case of Leferink's Ashburton partnership.
The detractors of cow barns say farmers can run the risk of overcapitalising their properties, which is something Leferink readily admits is a risk.
"People need to do their homework when they enter this field. It is not for the faint hearted."
He calculates that the farm can grow 10 to 15 per cent more grass because the land is not stressed over the cooler months.
Farmers have other environmental tools at their disposal. There's been the irrigation revolution - centre pivot irrigation technology that allows better management and less waste than the now almost extinct water dyke system.
Then there is "Overseer" - the on-farm decision support model helps users develop nutrient "budgets" for their properties. The model is jointly owned by the Ministry for Primary Industries, the Fertiliser Association of New Zealand and AgResearch.
Leferink says it's been a long time coming, but farmers are coming around to green principles, because they often make good business sense.
"I think farmers have come a long way. They are ready to come together and to reach solutions. They do not want to wreck the environment.
"Twenty odd years ago, effluent just went down the drain. That stuff doesn't happen any more, so I think we have come a long way already," Leferink says.
As Mackenzie sees it, the needs of the farming community and the environmentalists need not be mutually exclusive.
"Even though we are high-input, there is an opportunity to meet all the environmental outcomes that they want," he says.
"We don't want to impact on the environment but we also have to be profitable. It's very hard to be green when you are in the red."
• Jamie Gray travelled to Canterbury courtesy of Federated Farmers.
