Canterbury has the worst water pollution of any region in New Zealand – nitrates and pathogens from ruminants. The primary source of this pollution comes from high concentrations of urea in urine patches passed by dairy cows. The number of dairy cows in the region has grown rapidly to over 1.4 million due to massive irrigation development and a huge increase in the use of inorganic nitrogen fertilizer, (urea). The water pollution stems from ill-considered water use and inorganic urea. This pollution poses risks to public health, lost recreation and damage to aquatic ecosystems.

Investment in recent (subsidized) irrigation projects exceeds $500 million. This infrastructure is here to stay. Over allocation of the region’s water resource is self-evident and ECan now faces the slow process of mitigation as irrigation consents expire. There is presently a ban on new irrigation in the region.

Farming and business lobbying has resulted in the development of elaborate regulatory solutions giving the appearance that ECan and the landowners are actively trying to solve the problem through the actions of the 10 water zone committees and the Canterbury Water Management Strategy, (CWMS). These fail to treat the real disease which is inappropriate land use.

It is self-evident that restricting the use of inorganic nitrogen fertilisers is the single most effective and practical tool to slow the nitrate pollution that is occurring in the region’s once envied aquifers.

New Zealand farmers have dodged a bullet by being excluded from the emissions trading scheme, (ETS), despite pastoral farming contributing to nearly 50% of this country’s greenhouse gas emissions in the form of methane (CH4). Presently there is no means to manage methane generated from ruminant digestive processes despite the government funding intensive scientific research. Methane is estimated to have a Global Warming Potential, (GWP) of 28-36 over 100 years. CO2, the Global Warming reference gas had a GWP of 1. Increases of CO2 in the atmosphere will last thousands of years. (US EPA).

The New Zealand government has not included the manufacture of urea using natural gas at Kapuni in the ETS and by not doing so the government is massively subsidizing farmers from the increased CO2 generated from the manufacture of urea, higher methane levels resulting from increased stocking rates, increased levels of nitrous oxide, and water pollution from nitrate leaching.

Nitrous oxide (N2O) which is emitted as part of the nitrogen cycle during agricultural activities has a GWP of 265-298 times that of CO2 for a 100 year time scale.

In 1976 fertilisers accounted for over 20% of the energy input into UK farms as nitrogen application rose to 20x pre-war rates. Despite this increase stocking rates scarcely doubled despite a substantial rise in other inputs such as feed grains, lime, phosphate, potassic fertilisers (30x increase) and improved grazing management. This addiction to fertilisers made UK farmers vulnerable to price rises from the oil shocks. At this time New Zealand farming successfully based their enterprises on legumes fixing atmospheric nitrogen. A prescient R. J. M. May, Grasslands Division, DSIR, warned Zealand farmers of making the same mistakes that had been made in the UK in the light of the proposed Kapuni urea factory.

Banning the use of urea fertiliser on vulnerable soils such as Central Canterbury will achieve less water pollution due to:

Preventing leaching from nitrogen applications that exceed the uptake from plants
A modest reduction in cow numbers with minimal effects on net profitability
Less urine patches
Healthy soil ecology
Preventing industrial dairy farming on vulnerable high country soils and landscapes where cold weather compromises the development of legume based pastures

Discussion papers on National Freshwater Management Standards and ineffective plan changes through the CWMS are simply mechanisms to delay addressing an emerging environmental crisis.

Is it not better to tackle a problem at the source than to (ineffectively) treat the results?

All truth passes through three stages: First it is ridicule, second it is violently opposed and third it is accepted as being self-evident. Anon.

The majority of New Zealanders accept Global Warming is a reality.

We do not accept the present state of our water.

Should we accept our government’s short term appeasement of agribusiness lobby groups by omitting Kapuni urea from the ETS thus sending the wrong market signals to farmers while at the same time putting our environment at risk?

Footnote: Dr Peter Trolove is a retired veterinarian and President New Zealand Federation of Freshwater Anglers

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