BZE publication in cooperation with the Institute for Sugar Beet Research in Göttingen

Sugar beet has a very bad reputation when it comes to soil carbon, but it is unclear how this should be included in the product-related greenhouse gas balance of sugar. So far, the humus balance method has been the method of choice, which assumes a C loss of 0.76 tons of C per hectare per year due to row crops. In the BZE-LW we have 365 sugar beet sites, and using a certain statistical method we looked for a similar site without sugar beet cultivation for each site and compared the C stock. The result was that sugar beet sites had "only" 2.6 tons less C. This is significant and can be explained by lower C inputs (mainly roots), crop erosion and severe soil disturbance, but is still moderate after around 200 years of sugar beet cultivation in Germany. Furthermore, it can be seen that the change in C stocks on these sites is also less pronounced than the average of all re-sampled soils. A new equilibrium is therefore being established, which is not reflected in the humus balance method. Sugar beet grows for 6 months only, it is therefore always possible to grow a cover crop before. As this is happening more and more, sugar beet sites could even accumulate C.

The second part of the paper shows data from a crop rotation trial near Göttingen. The soil lost C in all treatments, but the crop rotation with sugar beet and mustard as cover crop had the lowest losses.

Conclusion: On sites where sugar beet has been grown for a long time, further C losses are not necessarily to be expected and sugar beet should always be preceded by a cover crop.

https://doi.org/10.1111/sum.70022