November 2019


Soil testing is a major part of what we do at Fertilizer New Zealand. Before we can make any sort of sensible recommendations there needs to be a clear understanding of what is in the soil and what needs to be added to grow a sustainable crop or pasture. It stands to reason that if nitrogen is required then there should be a test taken to show the need and then the advantage of applied nitrogen. It is our understanding that most soil tests don’t include a nitrogen test. If this is the case, how can farmers make informed decisions about how much is needed?  Clearly a case should be established as to why extra nitrogen should be applied and what the cost benefit would be.

There are many aspects to be considered before applying nitrogen. Here is just something to consider. There is a system in the soil called the nitrogen cycle. [There are many of these cycles which make up the soil’s ecosystem.] The nitrogen cycle if it is allowed to function will produce much of the nitrogen needs required to grow pasture. Part of this system consists of air in the soil. Compacted soils by their very nature contain very little air. The air around us has almost 80 percent nitrogen. If the soils have 25 percent air as they should, then that would mean nearly 80 percent of that air is nitrogen for free. Include into this equation clovers and this would give the soils even more nitrogen. On top of that is animal urine and earthworms. The list could go on. All of this is free to the farmer and is happening when the nitrogen cycle is active. This is the reason every farmer should have a good idea of how much nitrogen they have in the soil and manage their nitrogen applications accordingly.

It has been reported that the Lincoln University dairy farm has conducted studies which shows that a 25 percent decline in nitrogen applications has not resulted in a loss of productivity but rather it has shown that it had “maintained or increased profit”. In all probability, it could also show an improvement in animal health.

So maybe the latest Government announcement may encourage us to rethink our farming practices and this may also lead to reduced costs and increased profitability.