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Fossil Fuel Fertilizers v. Compost Teas on the Farm

Fossil Fuel Fertilizers v. Compost Teas on the Farm
Rebecca Hosking | Friday, 18th May 2012

Conventional fossil fuel derived fertilisers destroy soil life and wildlife yet they have become like a drug habit to farmers. Rebecca describes her head-to-head (or field to field!) trials with NPK versus homemade compost teas on the farm.

What makes our land so green but perhaps not so pleasant
Around the home and garden you may know it as Miracle-gro®, Phostrogen®, Baby bio®, Growmore® or by one of its other fertile names. On the farm its many forms may be referred to as 'super triple phosphate', Nitram®, '20:10:10', just 'nitrogen' or – rather euphemistically – fertilizer. On our farm it's simply known as NPK, the acronym of this compound's most common chemical ingredients – nitrogen, phosphorus and potassium.

Synthetic fertilizer was essentially developed to stave off the limits to population growth and it's been estimated that almost half the world's human population are currently fed as a direct result of its use. But, this once heralded silver bullet for 'feeding the world' has certainly come at a cost; from vast oceanic dead zones to accumulation of heavy metals in our top soils to the release of greenhouse gasses into our atmosphere.

I'm not going to get into debating the global merits or otherwise of synthetic fertilizer but, when it comes to our farm I will slam my wellied foot down with some defendable authority because there is another obvious drawback of NPK and that is its lack of sustainability in the true sense of the word. The P (Phosphorus) and the K (Potassium) are both mined from depleting mineral sources and the N (Nitrogen) is pulled from the air using large amounts of natural gas or coal.

Our goal on this farm is to create an economically, ecologically and socially resilient business so the notion of relying on a depleting, fossil fuel hungry overseas resource as the basis of fertility on the farm is completely nuts. However, stopping using NPK is not as straightforward as some might think. Even my father who has been merrily spreading it on the fields for decades describes it as a drug and farmers like junkies for using it.

The drug analogy isn't a new one but I don't think many people know quite how fitting it is on so many levels. Like a narcotic, the first hit is the best and from then on you're hooked.

One of the reasons the first rush is sooo gooood is that you actually still have functioning living soils at that point so you are genuinely adding 'extra plant nutrients' to an existing fertile system. I often wonder what wonderful growth rates my father and uncle must have witnessed when they first applied NPK to our then organic fields, what a hit they must have seen.

Naturally, essential plant nutrients and minerals in the soil are taken up by the soil biology. As the saying goes, "Once the mineral becomes life, it's available to all life," meaning once a mineral has been taken up by a soil microbe it's then a plant available nutrient or available to support the life of another microbe.

The sheer volume and variety of microscopic life in healthy soil is mind-boggling. Just one teaspoon of healthy organic soil carries around a billion soil microbes. If you're familiar with the work of such scientists as Dr Elaine Ingham or Dr Patricia Richardson you'll have probably seen incredible electron-microscope footage of this wonderful underworld.

It's a world full of fungal forests and peculiar plants, of bizarre little grazing herbivores that are prey to fang-toothed hunters that in turn are devoured by positively petrifying looking apex predators whose dead bodies are scattered by innumerable little scavengers. They are all their under our feet, unseen.

What's not so commonly known is when you first sprinkle on the NPK these microbes die off in their trillions with each tiny body releasing a small package of nutrients to the plant roots around them. To the naked eye we just see an impressive surge in plant growth but on the microscopic scale it is the apocalypse!.

The pitiful sight of the dead and dying
If, like us, you're one of those farmers or gardeners without your own electron microscope, there is one soil dweller we can observe that can tell us all we need to know about the life in the soil and the effects of chemical fertilizers – the earthworm. We all know that a soil rich in earthworms is healthy and fertile so you can imagine how distressing it was to find dead and dying worms scattered across one of our fields during the first rains after the NPK had gone down.

Like an addictive narcotic, once you start using synthetic fertilizers, it is a one way ride. Each application onto to fields burns off more and more soil biology which in turn severely reduces the amount of available minerals and nutrients from the soil to the plants. Each year you have to add a little more just to stand still and eventually it's a case of add the NPK or go out of business.

Holistic Rancher Greg Judy sums it up by saying, "When you put chemical fertilizer down on your farm you're killing your farms future, and the fertilizer companies are laughing all the way to the bank because you've now got sterile soil, and they know you've got to comeback to them to buy more of their fertilizer."

That's the trap my father and uncle are seemingly in, the only way they view they are going to get any growth out of our fields is by mainlining a direct hit of chemicals straight into the plants roots because they no longer can rely on the now impaired soil biology to help grow healthy plants.

It is possible to wean your farm off chemical fertilizer but it's not easy – it's called 'organic conversion'. As any farmer who has made the move to organic can tell you, going cold turkey from synthetic NPK can be a painful business. Curiously it is not just the land that becomes addicted, the whole way of working the land changes and, in effect, the farmer is just as hooked as his soil.

Intriguingly over the last couple of years since we've started applying pressure for my father and uncle to stop using the stuff, that junkie farmer mentality has unwittingly risen to the surface.

The tale starts four years ago, Tim (my other half) and I sat down with my father and discussed the damaging nature of synthetic NPK. He completely agreed with us and promised not to spread it on the fields on the west side of the farm as a small trial.

The depressing shaker sound of the fertilizer spinner
The following week I heard the unmistakable rumba-shaker noise of the fertilizer spinner... it was in the next-door field to me. Dad had purposely driven the long way round the farm to avoid driving past Tim and myself so he could 'fertilize' the fields he promised not to touch.

That was just the start or this behaviour; since then they've taken to hiding their NPK 'stash' behind the backs of barns in the hope we won't find it. Each year they may have got away with it if the deliveries hadn't been the same size as a grey whale.

They promise not to buy as much only to either buy the same amount if not more each year. Even the language they use sounds like an addict, "Oh I've only used a little bit", "I used to use a lot more then I do now – I've cut right back", "You're right we should give it up... but we've bought it all for this year now so we can't waste it".

The point being my father fully admits NPK is bad for wildlife and knows it damages the soils and is dangerous in waterways and doesn't like using the stuff yet, like a person with a habit, he'll go into complete denial when actually out scattering it on the fields.

The not so secret stash
As a result we realised pretty early on that if we were going to make any headway we needed to find an equivalent to soil methadone to try and wean the Old Boys off their magic white granules.

Our answer came in the form of cold brewed aerobic compost tea. Compost tea (or more correctly, we think, compost beer) has grown and grown in popularity over the past few years, particularly with gardeners but is now making headway into the world of farming. You can make it at home for next to no cost and, if brewed correctly, it's packed full of beneficial micro-organisms who then provide the 'fertilizer effect' by making biologically available those nutrients already present in the soil.

We started using it three years ago and risked a head to head challenge to prove to my father and uncle this bizarre alternative had some merit.

My father doused half a field in NPK and we sprayed the other half in compost tea. When it came to hay harvest time we all walked the two sides of the field to compare the results. Stupidly I never took any photos that day but although the sward wasn't as heavy with the compost tea it still held its own to the fertilized side. Particularly seeing we made the tea for pennies compared to the hundreds of pounds spent on fertilizing the other half. As a result of that trial, the following year we were given the go ahead to spray an additional field and this year a couple more.

In our case, the biggest benefit from using compost tea was to stop the NPK going down which is essential if our soil life is to start building again. Rule one for regenerative agriculture should be the same as in medicine – do no harm! The added bonus of compost tea is that by adding trillions of beneficial microbes it should also be helping to jump-start the biological cycle within the soil.

There are some farmers we know of who swear by compost tea and apply it in quantity several times a year but, for us, we see it as a temporary measure. By changing our land management and grazing practices, we hope to rebuild a truly healthy, self-sustaining cycle of life in our soils powered solely by the sun. Compost tea application will definitely have a role to play in getting things started but hopefully we won't have to apply it for too many more years. To use a thoroughly inappropriate analogy, compost tea is our starter motor and we will only be using it until the main engine kicks in.