Future Farming: Productive, Competitive and Sustainable.

What is it going to take for the support to shift from industrial farming to regenerative farming where Mother Nature is allowed to do her work? And how do we do this?

There are several areas that are important to this question and a major part of achieving this is in understanding our soils.
Many, many decades ago soils were high in organic matter. Early studies between 1839 and 1843 were conducted by the explorer and geologist Sir Paul Edmund [Count] Strzelecki in south- eastern Australia. Wanting to know why some soils were more productive than others he collected 41 samples of soil from both high and low productivity farms and had them tested. The results showed clearly that level of organic matter (soil carbon) was the key to productivity.
“The top 10 soils in the high productivity group had organic matter levels ranging from 11% to 37.75% (average 20%). The lowest ranking 10 soils in the low productivity group had organic matter levels ranging from 2.2% to 5.0% (average 3.72%” reports Dr. Christine Jones

These high levels of organic matter meant that water stayed in the landscape and that the land was resilient. Strzelecki found an 18-fold difference in capacity to hold moisture between the lowest and the highest. His data indicate that organic matter levels in the early settlement period were around five to ten times higher than in many soils today. The soil test data from Strzelecki is consistent with the writings of first settlers, who described soils in the early settlement period as soft, spongy and absorbent. The 1840s journal of George Augustus Robinson, for example, contains numerous references to the extremely fertile and productive soils encountered by pastoralists in the mid-1800s (Presland 1970).

Soil organic carbon levels in most areas have fallen dramatically since the time of European settlement. Glenn Morris (Morris 2004) extensively researched the water holding capacity of humus (an extremely stable form of soil carbon) and concluded that within the soil matrix, one part of soil humus could, on average, retain a minimum of four parts of soil water. From this relationship it can be calculated that an increase of 16.8 litres (almost two buckets) of extra plant available water could be stored per square metre in the top 30 cm (12”) of soil with a bulk density of 1.4 g/cm3, for every 1% increase (in absolute terms) in the level of soil organic carbon. This equates to 168,000 litres of water that could be stored per hectare, in addition to the water-holding capacity of the soil itself (Jones 2006).

The flip side is that the same amount of water-holding capacity will be lost when soil carbon levels fall. Low soil moisture and low levels of soil organic carbon go hand in hand.

This reduction in soil carbon content represents the LOSS of the ability of soil to store around 504,000 litres of water per hectare.

 

Inspired by Walter Jehne’s presentation at the recent OAA conference: Future Farming: Productive, Competitive and Sustainable and acknowledgement to Dr. Christine Jones