Editorial
Ian Lynn collecting samples during the high country carbon survey.
This issue of Soil Horizons reports on our soil carbon (C) research addressing the need to enhance the terrestrial C pool and reduce carbon dioxide (CO2) emissions to the atmosphere.
Soil C provides the framework for soil organic matter, the life support system of the soil, and makes up about half of its composition. Globally the top metre of soil contains more C (about 1500 Gt (billion tons), than the combined C in the terrestrial vegetation (»600 Gt) and atmosphere (»750 Gt).
Some cultivated soils have lost up to two-thirds of their original soil organic matter (SOM), and this depletion is accentuated by intensive land use for global food supply.
When soils no longer accumulate C, because of cultivation, erosion or drought, existing reserves continue to be lost by leaching as dissolved organic C, and by oxidation to the atmosphere as CO2. During the period 1850–2000, global emissions of CO2 resulting from land-use change and soil cultivation, are estimated to be about half of that due to fossil fuel combustion.
Restorative management of agricultural soils not only reduces the rate of enrichment of atmospheric CO2 but also has positive impacts on food security, agro-industries, water quality, and the environment.
Researchers in Landcare Research, in New Zealand and globally are focussing on the assessment of soil C stocks and mitigation strategies to slow down, halt or even reverse loss of organic C from soils.
In this issue of Soil Horizons we present a few snapshots of our current soil carbon research activities at Landcare Research. These include articles on assessing soil C stocks, soil C storage mechanisms, soil C measurement, soil C change and the processes involved, quantifying losses, mitigation strategies to reverse soil carbon losses and modelling.
This issue of Soil Horizons pays tribute to Peter Stephens, creator of this newsletter, and a much respected science leader.