Tuesday, 10 January 2017

Soil Carbon

One of the biggest arguments for excusing agriculture from New Zealand's emissions trading scheme (ETS) is that we farmers have no real prospect for mitigating these emissions. The EPA's chief scientist has recently argued that
"turning down agricultural emissions means altering biology - or getting rid of animals" 
Dr Rowarth indicates that both of these options are doomed by economic realities. I was puzzled because the biological farming methods we and others use are largely focused on fostering and cultivating (altering) soil biology, and here was the chief EPA scientist intimating we are mad.

Our working hypothesis goes like this:
  • we can use liquid foliar feeding (alongside dry ground-spread) to stimulate pasture growth
  • the diverse (salad bar) plants will share some of the nutrients with the soil through root exudates
  • the soil critters (worms, beneficial bateria & fungi) have symbiotic relationships with the plants, supplying them with macro and micro-nutrients.
There is a critical feedback loop here: we feed the soil biota & in return those beneficial critters scavenge around, scooping up nutrients and delivering them back to the plant in an available form.

Most farmers know that P gets locked-up in the soil. That's why the fert reps say we have to keep putting moron, even when the soil tests say we have plenty. We sacked these twits years ago. Since then we've been using small amounts of slow-release organic P and like to think that our soil biota are helping to unlock the abundant P reserves we see in our soil tests.

We reckon that farming can and should be regenerative: we are trying to build the soil rather than deplete it. Traditional agricultural systems have been terrible at conserving carbon but recent science suggests that alternative grassland management systems can indeed regenerate the soil and sequester atmospheric carbon.

If you thought these soil carbon prospects might be of interest to the chief scientist for NZ's EPA, you are sadly mistaken. When I asked Dr Rowarth recently why we don't care about monitoring soil carbon she had three reasons: NZ already has lots of soil carbon, it comes & goes with drought and its very hard to measure. I don't buy any of these reasons: they sound like excuses to me.
  • The current stock of soil carbon is irrelevant except as a baseline measure: farmers should be accountable for changes in soil carbon stocks. 
  • Droughts as a source of soil carbon volatility could be easily managed in a regulatory regime - for example with a rolling average over a few years.
  • And technology is rapidly cutting the cost of measurement.
To be clear, I am not suggesting that it is particularly easy to bring soil carbon into the ETS. Those opposing the idea have no shortage of roadblocks to promote. Instead, I am arguing that New Zealand should be working actively towards surmounting those roadblocks. Those controlling the relevant public funds are actively denying that this is warranted, but seem to have no science on their side - just blind faith in the status quo.

It is particularly distressing that our Environmental Protection Agency seems more interested in excuses than in pushing for (or even admitting there might be value in) scientific effort directed towards this particular form of "environmental protection" for which we pay our taxes.

1 comment:

  1. Getting rid of animals is an emotive term for land use change. You have to be blind or a bit stupid to assume that if some land is being used for something, that this is all that it can be used for. For an obvious example, we drove down the Wairau valley this summer where you can observe clearly sheep farms being displaced by vineyards. Apparently this "getting rid of animals" is not "doomed by economic realities".

    What you are describing is something less observable, but no less effective or dynamic.

    What has puzzled me throughout the carbon debate is why policy makers can't see that land use in NZ is dynamic, changing all the time, and a good thing... And that this is the result of constant innovation by the primary sector.

    I think put soil carbon and methane into the ETS in a meaningful way and let farmers innovate--like they do constantly anyway.

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