The short and obvious answer is to stop buying it. Where then does nitrogen come from? The atmosphere that we breathe is 78% nitrogen so there’s absolutely no shortage of it.
How then do plants get enough of it for maximum growth. Plants grew abundantly long before the Haber- Bosch process was developed and urea was available for farmers to purchase.
The ammonia urea plant at Kapuni in the Taranaki was built not because New Zealand pastoral farmers required more nitrogen, but because there was an abundance of cheap energy from the development of the off-shore Maui gas field.
As it is only since the late 1990’s that the regular use of urea has become widespread, the reliance on it for growth has been an experiment and we are yet to fully appreciate the long-term consequences.
Official pasture growth data from the Ruakura Research Station prior to the use of urea, showed annual pasture growth to be regularly above 18,000kgDM/ha from a number of sites in the Waikato.
Today, annual growth of 13,000kgDM/ha for the same region, a drop of over 25%, is regarded as common, and even normal, with increasingly wide seasonal fluctuations blamed on climate change.
That’s not the experience of all farmers. An increasing number of farmers have over the last twenty years profited from growing clover to provide more than sufficient nitrogen to maximise annual growth.
Profiting because they are not spending as much as $500.00/ha on something that is not necessary and in the long term has shown to increase nitrate-nitrogen in ground water.
The key to their success is creating the conditions that favour the growth of large leafed, strong stemmed clover. That is done by increasing the amount of calcium available for plant uptake, necessary because clover contains up to 4 times the calcium of grasses.
Agricultural lime is the cheapest and most abundant soil fertiliser available and therefore is often undervalued.
However there is another important step. The calcium in lime is not water soluble and for plants to access it beneficial soil biology must be present.
The mainstream position on soil biology is that it is always present and because introducing beneficial fungi and bacteria has been shown to be difficult to achieve in the short term that essential aspect can be ignored.
Changing soil biology to benefit pasture is achievable particularly when lime and microbes are added at the same time. Soil is a digester and operates in much the same way as the gut of an animal or human.
Add something different and it takes time for the microbes to build sufficient population for full digestion to take place, the reason that animals are transitioned onto crop.
Probiotics are increasingly accepted as a valid way of improving human gut function and the same principles apply to soil.
With soil constantly under pressure from treading, too much moisture in winter and excess heat over summer, introducing beneficial biology speeds digestion of dung, dead leaves, and old root matter that has accumulated over summer.
Functional Fertiliser Ltd developed two soil improvers over twenty years ago. These were designed to be applied as part of a total nutrient programme that contained both essential phosphorus and sulphur, along with any other necessary input.
CalciZest containing lime was designed specifically to stimulate clover growth. DoloZest containing Golden Bay Dolomite provides both calcium and magnesium. Both contain the same proprietary mix of beneficial fungi and bacteria selected for their role in digestion and increased nutrient uptake.
An application of either this autumn is a low cost and highly effective way of reducing over time the dependence on urea as the provider of nitrogen. For more information call Peter on 0800 843 809.
Peter Burton, January 2022