Dairy farming harming water

Parliamentary Commissioner for the Environment Dr Jan Wright
Parliamentary Commissioner for the Environment Dr Jan Wright

Calls to limit dairy conversions are being made in the wake of a new report confirming fears dairying is polluting waterways.

The Parliamentary Commissioner for the Environment today released a report on water quality which highlights how the country is facing a ''classic economy versus environment dilemma''.

The report highlights how nitrogen and phosphorus are valuable nutrients on land as they help plants grow, but above certain concentrations in water they became pollutants.


Environmental advocates are calling for urgent action to limit the conversion of beef and sheep farms to dairy to avoid a "freshwater quality disaster".

Forest & Bird say moderation is essential to stop the dramatic decline in the quality of New Zealand's waterways.

Advocacy manager Kevin Hackwell said the PCE report confirmed what everyone knew - that dairying conversion rates could not go on without causing a "dramatic reduction" in water quality.

"What no one wants to talk about is that the current 'white gold rush' is leading New Zealand to a freshwater quality disaster."

He said even if all dairy farmers employed industry best practice, nitrogen levels would increase and make swimming and fishing in many of our lakes and rivers a thing of the past.

The Green Party is also urging the government to set tougher standard to ensure the recreational water quality of the country's waterways.

Water spokeswoman Eugenie Sage said nitrate pollution in Canterbury's rivers, lakes and streams was predicted to increase by 45 per cent between 1996 and 2020.

This proved that mitigation measures, such as riverbank planting, were not enough to offset the increased nutrient load from increased land use change.

"New Zealanders want to be able to swim in our rivers," Sage said.

Fish & Game chief executive Bryce Johnson said the PCE report vindicated the organisations "dirty dairying" campaigns against the industry.

He said that even with good management practice on farms, such as reducing nutrient loss, further declines in water quality from dairy intensification would continue if expansion was not limited.

"It [the report] serves as a stark warning that the nation is at a crossroads; we can either continue with the Government's and primary production sector's agenda of doubling agricultural output by 2025 - completely wrecking the environment, our waterways, our estuaries and beaches, our tourism sector, our international brand, and the kiwi way of life in the process - or we can look at smarter ways to grow the economy."

Johnson said the report showed intensive agriculture had gone too far and was "out of control".

He called for a regulation of the dairy industry.

"Further unregulated dairy expansion is not in the best interest of our economy or our environment.

"If the Government and the dairy industry fail to act on the warnings in this report they will essentially be giving two fingers to the next generation."


Dr Jan Wright said the conversion of beef and sheep farming to dairy farming land had increased nutrient loads on waterways.

''It is almost inevitable that without significantly more intervention, we will continue to see an on-going deterioration in water quality in many catchments across the country, particularly in Canterbury and Southland,'' she said.

''Unfortunately, this investigation has shown the clear link between expanding dairy farming and increasing stress on water quality. Even with best practice mitigation, the large-scale conversion of more land to dairy farming will generally result in more degraded fresh water.''

When sheep/beef farms are converted to dairy farms, annual losses of both nitrogen and phosphorus increased.

Too much nitrogen and phosphorus in water lowered its quality by causing excessive growth of weeds, slime and algae, as well as affecting insect, fish and waterbird populations.

According to the report, some  283,700 hectares of land has been converted to dairy between 1996 and 2008, at the same time sheep/beef farming land decreased by nearly 500,000ha.

Canterbury had the highest conversion rate with 122,500ha, followed by Southland with 111,900ha.

The report predicts that by 2020, another 99,600ha of Canterbury land will be converted to dairy farming, and that nationally up to 370,300ha will be turned into dairy farming land.

Drawing a correlation between regions with a significant increase in dairy farming and those with large increases in nitrogen loads, Wright said the rapid growth had led to a ''big increase'' in the concentration of nitrogen in waterways.

Canterbury, which has highest rate of converted land, had a 27 per cent increase in nitrogen loads between 1996 to 2008.

Wright predicts between 2008 to 2020 nitrogen loads will increase by 15 per cent in Canterbury, and nationally there will be a six per cent growth. Likewise, phosphorus loads are expected to increase in Canterbury by three per cent between 2008 to 2020.

The effect of increased nutrient loads on water depends on it vulnerability. For example, in a river that flows swiftly to the sea, nitrogen and dissolved phosphorus in the water stays low because of its frequent flushing.

''Ongoing and increasing nutrient loads will generally lead to worsening water quality - more degraded lakes, more turbid (cloudy) estuaries, greater frequency and duration of algal blooms at swimming spots and elsewhere, declines in the insects, fish and birds that rely on these ecosystems, and more water wells and surface water that exceed nitrate toxicity limits for drinking,'' she said.

''Unfortunately, if we continue to see large-scale conversion of land to more intensive uses, it is difficult to see how water quality will not continue to decline in the next few years. This is despite the best efforts of many.''

The report also outlines ways nutrient losses could be mitigated.

These include, disposing of town sewage and dairy shed effluent on to land to use as a fertiliser, nutrient budgeting, fencing streams and bridging crossings.

''I applaud the effort that is being put into environmental mitigation on dairy farms. Unfortunately, it is particularly difficult to control nitrogen. Nitrogen - in the form of nitrate - is so soluble that I think of it as the 'elusive' pollutant.''

Irrigation New Zealand chief executive Andrew Curtis said the report did not tell them anything they did not already know.

''IrrigationNZ believes win-wins are possible for agriculture and the environment and we have many examples within New Zealand of how intensive land use can be managed to significantly erduce its footprint, particularly under irrigated agriculture,'' he said.

''The PCE needs to take more note of recent innovations in land use management.''

Curtis said everyone acknowledged that current and future land use needed to be carefully managed in order to grow the economy and maintain and improve water quality. 

He said the question they need to tackle was how to grow farming while improving water quality. 

''New Zealand needs to spend its resources on innovative solutions, not beating itself up,'' he said.


Dairy giant Fonterra are committed to "lifting environmental performance" to ensure New Zealand preserves it's clean green image.

Fonterra group director cooperative affairs Todd Muller said the organisation shared Wright's concerns about the pressure on the country's waterways and recognised they role they had in improving water quality.

He said global demand for dairy had spurred on the increase in dairy farming in the past 20 years.

This had been economically beneficial to New Zealand and farmers had responded well by managing their impact on water by fencing waterways, managing raceways, tracks, paddocks and effluent, and reducing run-off through riparian planting. 

"Fonterra and our farmers have undertaken a significant amount of work to protect waterways, but we recognise there is more to do," said Muller.

Fonterra highlighted that the report recognised that water quality had been shaped by cumulative effects of increased land use by various industries.

Muller said Fonterra was working with scientists and other organisations on improving nutrient use and providing farmers with information to manage farming systems efficiently.

"We are absolutely committed to lifting environmental performance and ensuring on farm management practices meet national and regional limits that preserve New Zealand's clean green image."