Traditional farming practices revolve round complete turning over of soil and the burial of any weeds. The reasons for this has been presumed requirement of a good fine seedbed for the germination of the food crop, and a reduction in the weed growth.

In general the top 50cm of soil contains a far greater proportion of the total soil carbon than deeper layers. This is due to the natural rooting depth of grasses, sedges and the like, which even in forest situations will tend to provide the bulk of ground cover. Similarly the soil fauna, earthworms and the like, live in the topsoil where moisture and air are readily accessible. SOC is a very fragile element and any movement that increases aeration and direct exposure to sunlight will result in its oxidisation. Thus traditional agricultural land tillage practices result in a lowering of soil carbon and a degradation of the soil health.

Similarly removal of the above ground cover i.e. grasses from the arid and semi arid (ASAL) rangelands of the world, will also impact on soil carbon stocks. There maybe no direct movement of the soil, in this case, removing the shading aspects of grasses results in the soil becoming excessively hot and increased evaporation. This destroys the natural habitat for soil fauna and organisms leading to a loss in carbon.

For both scenarios the replacement of soil carbon will result in an increase in the productive potential of the land. Conservation Agriculture (CA) with its use of minimum tillage and retention of crop and other residue very quickly starts this process. Over time the action of crops and soil micro bacteria and fungi will carry this carbon down below 50cm where it is relatively safe from human destruction. Effective rangeland management that returns the natural grass cover and shades the soil has a similar effect. An added advantage here is that within the East African rangelands many of these natural grasses are of the C4 type. On of the characteristics of the C4 grasses’ is that they are very deep rooting and thus can sequester carbon below the 50cm mark.

Thus Agricultural Carbon is an important component in any climate change discussion, as well as a powerful tool in steps to mitigate total green house gas emissions.