Wednesday, March 11, 2009

If Permanent Grasslands are Cropped the Soil Carbon Does Not Change

The headline is provocative but it seems this is the case, at least in temperate areas of north America.

And one major point to emerge is that some of the earlier modelling assumed the areas would be ploughed.........which might just NOT be the case in many areas today. This is a seemingly critical flaw being used in calculations about the potential for carbon to be emitted from grassland converted to farming.

Farming practices have moved on, but the climate scientists have failed to rejig their algorthims!

is a direct link to a media release about the research findings, recently published in Soil Science.

In the NT, and much of northern Australia, it is likely that any conversion of pasture land to cropping would be done under a no-till system, or at worst with minimum tillage. It is also likely that cropping / faming would not occur continuously for a number of years but rather have some alternation between farming and a pasture phase of several years. An exception to this would probably be the development of irrigated areas in the Ord Irrigation Area, where native vegetation is typically annual savannah grasslands.
So it seems that ploughing is the culprit, not cropping per se.

It all adds to the conundrum that is soil carbon storage.

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