Growth spurts 3: dust, dirt and the periodic table

High school chemistry flashback ... aaargh!

You know that feeling when the dentist is picking through your mouth and not tutting at you and not poking at anything that sends you half out of the chair and you're almost convinced that maybe this time there'll be no work required and you feel all weirdly excited? That's how we felt in early 2012 while we waited for the results of our soil testing. 

We knew our dirt was acidic and would need liming but had no real idea about all the other elements that make up soil and in what proportions they'd arranged themselves at Muntanui.

If we re-visit the dental analogy, it turned out we needed a root canal, a wisdom tooth extraction, three additional one-hour appointments and some serious anaesthetic.

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The damage

• Soil pH of 5.3 -- strongly acidic, which means a calcium deficiency. Given that the optimal availability of nutrients to plants is reached at a pH of 6.5, we had a lot of lime to spread.
  
• Deficient in phosphorus -- most NZ soils are, which is a bummer because it's so vital for flowering, fruiting and root growth. One way to increase one's soil phosphorus level is to buy a rock sticking out of the ocean, entice lots of seabirds to hang out there for years and years and years and then mine the guano. Or one can pour sulphuric acid over ground up phosphate rock and: voila! Superphosphate! Ewww! Or one can do what we did and opt for RPR (reactive phosphate rock), which is kinder to the environment.
  
• Deficient in sulphur. This element is essential for the manufacture of chlorophyll, the formation of nitrogen-fixing nodules on legumes, for disease resistance, growth and seed formation. Pretty important, then. We opted for elemental sulphur for that "kindness to the environment" reason mentioned above.
  
• Deficient in magnesium, essential for photosynthesis -- which is why plants with a magnesium deficiency turn all yellow and spindly and look sad and kind of betrayed, radiating "Why?" at you in their mute suffering.
  
• Deficient in trace elements: cobalt, boron, selenium. Cobalt is the name given to a very beautiful shade of blue. It's also an element needed by legumes for the formation of nitrogen-fixing nodules. (I keep mentioning legumes because clover is a legume and if it doesn't grow well, we end up with nitrogen deficiency in our pastures and that's a very sad state of affairs.) A boron deficiency means we wouldn't be able to grow good clover or brassicas (turnips, kale etc.) for livestock and people feed. It's necessary for cell division and in the formation of fruits and seeds. As for selenium, not all plants seem to need it but humans and animals definitely require its anti-oxidant properties. NZ soils (particularly in the South Island) have low concentrations of this element, so it made sense to throw a pinch or two up hill and down dale at Muntanui.

The fix
We should've had our soil amendments spread in autumn last year but we kept getting distracted by saffron harvesting and livestock emergencies and Farmer Wan working in Oz, etc. The spreading finally took place this year, on 12 June -- a bit too close to winter but again, there were other priorities.

On the day, a nice man rocked up in a big truck, opened a valve in said truck and drove up and down our lumpy paddocks releasing white powder until it ran out. Then he headed away to where his trailer was parked, re-filled, came back and drove around again.

This went on for about an hour. The air was so thick with white dust we couldn't see anything else. The tiniest of breezes sent it wafting down the road to our neighbour Helen's place. She later thanked us for the free fertiliser.

I was working in the tunnel house at the time, feeling smug because I'd had the foresight to wear a mask. It made no difference -- I still ended up with the worst sinus infection of my life. I was sick for three and a half weeks. So important safety tip, people: when your paddocks are being spread with 18.42 tonnes of bacteria-inoculated fertiliser, go and play somewhere upwind, preferably a few kilometres away.

Spring will show us how effective this process has been. We'll probably have our soil re-tested in summer and I'll get to experience that dental chair anticipation all over again. I'm hoping for a quick clean and polish. Fingers crossed.

Posted by Farmer Nik