Tuesday 7 January 2020

Day 2 of the Beetle Bank blitz

Another early start this morning but given the level of amenities at Ringwood Travel Lodge I am at least getting early nights!
Field kit present and correct for another morning
First stop was Woodyates farm - two banks here, one about 22 years old, the second created last year.

Bank 1 - a venerable c. 22 years old

Bank 2 - produced last year following the line of some power cables
Both these banks are quite different from yesterdays (and look at the Pentridge one, last stop today as well) which highlights I guess what a simple concept Beetle banks are - they really are just a bank of soil that is left uncultivated. They are produced by farmers turning the ploughed top soil onto the line where they want the bank. This makes them easy to produce but might complicate comparing how the carbon builds up over time between banks.

Another contrast with yesterday was that these soils are quite chalky - you can see the creamy coloured bits of stone in the photos above (and below).
You can see the white chalk at the bottom of the "soil sample" on the left and the brown colour of the overlying soil on the right
Normally soils form through a combination of silicate minerals in rock breaking down and organic matter accumulating. Chalk bedrock is largely calcium carbonate, it doesn't have many silicate minerals to break down; typically the chalk just dissolves leaving very few soil minerals behind, so chalk soils are often very thin. The good news is that this means you don't have to sample very deep to get to the parent mineral material, the bad news is that you can spend a lot of time trying to core through rock!

So the shallower samples vs trying to core through rock kind of cancelled each other out and I didn't make really quick time. I did however, have time for a final field at Pentridge farm - again this was a "new beetle bank" and was on my list for tomorrow so I got one ahead.

The bank was a bit of a monster - the photo doesn't really do it justice, far higher than the others I've seen so far, with wide strips on either side that weren't cultivated.
The Pentridge beetle bank
Again, you can see the chalk quite clearly and the soils in the fields were rather shallow. I managed to finish just before the light gave out on me (the last time I did torch lit field work was with Stuart Black and Tracy Buckby in the Rio Tinto about 20 years ago I can't recommend it).

You can tell that it's getting dark (despite the camera's best efforts) as the lights on the GPS base station and clearly visible.
The drizzle started again and I packed up in the dark. Tomorrow's weather looks OK and it is off to Cranbourne for two days of banks.

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