Nitrogen research was a waste of money

Better soils
with Brett Petersen
Kiwi Fertiliser & Golden Bay Dolomite

About eight years ago MAF, Fonterra and the fertiliser co-ops started wasting $10m on nitrogen research. I don’t know how far they got, but if it needs mitigating, nothing has changed.

This approach is attempting to preserve the status quo and as such is irresponsible. A quick look at urea history shows us why business as usual is important.

In 1979 the first shipment brought 16,000 tonnes into NZ. In 2016, it was 560,000 tonnes imported, and 260,000 tonnes manufactured locally. That’s 820,000 tonnes. Now that’s a $39m business to be protected!

Now 2008 was a drought year, but a farm (NR) I was supervising increased production by six per cent. We used 9kg/ha N. Most drought-affected farms and a BOP Focus Farm decreased production by 15 per cent.

The BOPFF’s N usage was 191kg/ha. That is 21 times as much and for what? Grass growth was very similar with 12,900kg/ha on BOPFF and 12,400 on NR.

In 2009, NR was up a further 12 per cent; N was 36 units. The BOPFF was down eight per cent with 235 units of N. Pasture analysis N for NR in 2009 averaged 4.6 per cent. So, what is the big deal about applying nitrogen? When N is applied, farmers sees a visual difference, but that does not translate to quality. The cows need to eat more, but they can’t eat enough. Not to mention digestion problems as reduced cud chewing allows undigested grass to pass through their stomach’s system. The increase in growth lasts for two grazing rounds, then there are two rounds with decreased growth. Nitrogen carries other nutrients out of the soil.

Free nitrogen

There are 74,000 tonnes of free nitrogen above every hectare. Most farmers miss out on this resource because their soil-life cannot capture it. To access this N, conditions apply. Appropriate calcium and magnesium percentage; available phosphorus and iron; cobalt and molybdenum. It does not pay to turn the tap off, but gradual reduction works fine. Most (not all) dairy farms have too little Ca and Mg; too much P, adequate Fe; too little Co and plenty of Mo. Some of these nutrients are being applied direct to the animals and pastures. That short circuits the natural systems and costs more in the long run with a never-ending list of animal health and reproduction problems. To capitalise on free N, get a PAL soil test through a Kiwi Fertiliser representative. They are competent biological and soil fertility consultants expertly trained by Neal Kinsey and others.

Soil carbon

Nitrogen can be sprayed on with buffering substances, usually fulvic acid. A carbon source such as biochar accompanies any solid fertiliser including nitrogen. If N is applied without C, bacteria, that have a C:N ratio of 5:1, have no choice but to consume soil organic matter to maintain that balance. Research shows that every kg of excess N causes the loss of 100kg of soil carbon.

Nitrate pollution of water, milk, land, pasture, animals and humans are symptoms of a degraded environment. When are we going to stop doing what what’s not working and apply some simple common sense that really works? Please remember, our nitrogen balance relative to production is the worst of any OECD country. Identify what drives profit; not production.


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