The basis of claims made by Greenpeace in support of its petition to ban use of all synthetic nitrogen fertilizer by 2024 have been called mischievous and misleading.
For example, Greenpeace likes to hammer the point that New Zealand had the highest rate of increase in inorganic nitrogen fertilizer application out of OECD countries from 1990 to 2004. That’s true, but as Federated Farmers GM Policy and Advocacy Gavin Forrest points out, the NGO neglects to mention our farmers started from a very low base and were late adopters of the technology. Countries in Europe were applying it at much higher rates much earlier than New Zealand so that when we did adopt it, our rate of increase outstripped others.
According to 2018 data, New Zealand has the 14th highest nitrogen balance out of 38 OECD member countries. This suggests New Zealand farmers are on part with other OECD countries in terms of nitrogen use.
Gavin, who appeared on-line before the Environment Select Committee earlier this month with national board member Chris Allen and North Island Policy Manager Dr Paul Le Miere, said Greenpeace’s singling out of bagged nitrogen from that supplied by clover or animal urine/dung was “a red herring.
“Nutrients are vital to the growth of plants – plants that we feed to animals and well as plants we consume ourselves. Nitrogen is one of those vital nutrients.”
For plant growth, it makes very little difference what the source of the nitrogen is, Gavin said.
While acknowledging too much nitrogen in some waterways is a real issue “…it’s not about banning the use of something, it’s about the wise use of it.
“It’s about the management of the whole farm system rather than any one input that matters to both the farm itself and the effect of farming on the environment.”
Nitrogen fertilizer is very expensive, and farmers don’t waste it, Chris told the committee. Over the last 20 years, farmers have increasingly adopted best practice, and precision agriculture technologies, to achieve “the right amount of product, in the right place, at the right time.
“We don’t go doing it like our granddads used to do – just putting on 250kg a hectare of superphosphate.”
Sophisticated techniques involving soil testing and moisture analysis, GPS electromagnetic mapping to guide what nutrients are missing for the intended crop and pasture on different places on the farm, and even different places in the same paddock, are about “bang for buck” and looking after the environment.
And this isn’t just the arable sector and irrigated land, Chris said. Pastoral farmers look to Spreadmark-certified contractors who can calibrate their machinery to take advantage of soil mapping and provide proof of placement.
“What the leading edge guys were doing five years ago is now commonplace.”
While precision agriculture is certainly easier on irrigated and flat land, hill country farmers have the ability to spread fertiliser evenly or variably using calibrated “top dressing” GPS guided aircraft, Gavin said.
The vast majority of farmers are lifting their game on this front, and not just in response to new Essential Freshwaters regulations but part of a continuous improvement attitude that farmers and growers have taken for over 40 years as they respond to international market requirements.
An additional challenge is that the efficacy of clover nitrogen fixation that our farmers had relied on prior to 1990 has been severely hampered by clover root weevil. The rise in use of bagged fertilizer has been to a significant degree because of that. The good news is that despite the increase in the use of bagged fertiliser, according to government records, the amount of nitrogen lost off New Zealand livestock farms has been stable for 20 years.
And the ability to employ much more targeted synthetic nitrogen fertilizer, precisely when the grass or crop needs it to maximise yield, is a significant factor in the productivity boosts that have driven the 250% increase in export income from the primary sector since 2004.
The Federated Farmers submission on the Greenpeace petition also highlight the finding from AgResearch that a ban on nitrogen fertilizer would lead to an estimated drop in gross output from our primary sector by $19.8 billion, a drop in Value Add (GDP) of $6.7 billion or over 2% of national GDP, and a reduction in employment of 73,760.
Gavin noted that Greenpeace mischievously linked the synthetic nitrogen issue to its campaign for a much-reduced dairy industry in New Zealand. But the rise of dairy land use, and the relative fall of sheep farming, was about economic and market demand factors, not use of fertilizer.
The facts are that the increase in the loss of nitrogen from New Zealand dairy farmer since 2002 (22.7%) is the same as the increase in the area in dairying in New Zealand (23%). Off the back of this the number of cows increased by 31% and milk production has gone up by a massive 60%.
“So the footprint in terms of nitrogen per kilogram of output has dramatically reduced, and the divergence has been particularly marked since 2008, with an astronomical increase in production and a corresponding relatively low impact on the environment,” Gavin said.
Also, importantly this increase in dairy land has been offset by the decreases in beef and sheep land and so the amount of nitrogen lost off NZ livestock farms has been stable for 20 years. In fact, pastoral farmland has decreased by nearly a million hectares in the last decade, driven by increases in horticulture, arable, forestry and urban areas.
Paul said while clover could be used to replace some synthetic nitrogen as a nutrient source should that be forced on the sector, production would take a significant hit. But for fruit, vegetable, seed and other arable crops, the impact on production would be “massive”.
Similar points made by Federated Farmers to the Select Committee were also made by the Ministry for Primary Industries. Even the Ministry for the Environment said the environmental gains from a full phase-out might of synthetic nitrogen fertiliser would not be as significant as suggested due to its uneven impact on different sectors, and because alternative nitrogen sources are available.
“Before moving towards a full and rapid synthetic nitrogen phase-out, time should be allowed for the latest climate change and freshwater measures, including those in the Essential Freshwater proposals, to demonstrate their effectiveness,” MfE said.
ESR research finds no link with nitrates in drinking water and bowel cancer
If it was thought necessary to cut back the level of nitrates in New Zealanders’ diets, authorities should look at controls on green leafy vegetables rather than drinking water.
That was a message from Federated Farmers North Island Policy Manager Dr Paul Le Miere to the Environment Select Committee when fielding questions from MPs on recent media publicity about nitrates in water and our high rates of bowel and colorectal cancer.
Dr Le Miere referred to a report earlier this year from scientists from independent government crown research institute ESR and the Food Safety Science Research Centre (NZFSSRC), which found that the combination of biology, chemistry and exposure assessment suggests it is highly unlikely that nitrate in drinking-water, or in our food, presents an increased risk of cancer.
The research showed 80-90% of nitrates we ingest come from green vegetables, Dr Le Miere said.
Drinking water accounts for less than 10% of the nitrates Kiwis consume. Most drinking water is ingested either in a ‘food-like’ form (tea, coffee, porridge, etc.) or drunk together with a meal, or within an hour of eating, in which case the nitrates are likely to be cancelled out by antioxidants in food.
Nitrate in drinking water is no different to nitrate in food. Nitrate in water is generally ingested with food and so the body processes it like nitrate in food. There is no plausible rationale for analysing nitrate in water and food independently.
A much-cited Danish study, and also related studies, hypothesised that perhaps nitrates in drinking water that was consumed on its own could cause cancer. However, the ESR and NZFSSRC report said this was extremely unlikely.
The report said the amount of nitrate adults in New Zealand ingest in drinking water, on its own and not in close temporal association to food consumption, is 2.6% of total nitrate exposure, while in children it’s just 0.7%.
We also need to remember that nitrates are beneficial to human health in many ways. The body turns nitrates into nitrites, which combat bacteria in the mouth and stomach, and nitric oxide that makes our arterial walls flexible, which guards against heart disease and stroke.
It is known that what we eat, our alcohol consumption, smoking, age, exercise and genetic factors can all affect the rates of bowel cancer.
Dr Le Miere agreed that New Zealand does have high rates of bowel and colorectal cancer, but they have been going down since the mid-1990s.
“There’s no link. There’s no causation there either.
“Obviously, we have an open mind and as more research comes through it should be looked at,” he said.
“I think at the moment, until the Ministry of Health or other parties come up with authoritative research, we have to take what our crown research institutes have put forward as a scientific basis.”