Using preceding crop effects for climate smart sugar beet (Beta vulgaris L.) cultivation
The global warming potential (GWP) of crop cultivation (carbon dioxide equivalents (CO2eq) associated with the production and use of agronomic inputs+nitrous oxide emissions) should be minimized since a ‘climate smart’ label will become economically valuable in future. The choice and succession of crops in a cultivation system are rarely included in the comparison of methods for reducing GWP. This study elucidated the effects of different preceding crops (grain pea, silage maize, winter wheat) on GWP by agronomic inputs in sugar beet cultivation. In addition, the relation of the GPW to the energy yield was assessed as the global warming intensity (GWI). The study was done based on a field trial in Germany (Lower Saxony). The GWP of sugar beet cultivation as well as the GWI differed due to preceding crops (2.1–3.1 Mg CO2eq ha−1 and 6.9–10.8 kg CO2eq GJ-1, respectively). Values were significantly different between treatments with grain pea and silage maize as preceding crops. The cumulative GWP differed between the two years of crop successions (4.9–7.2 Mg CO2eq ha-1) with significant differences between the treatments with grain pea and winter wheat. The GWI as the average of the two years of each crop succession was in the range of 9.8–17.3 kg CO2eq GJ−1 and differed significantly between the treatments with silage maize and winter wheat. Thus, the choice of the preceding crop can contribute to a climate smart cultivation of sugar beet. Moreover, this study offers a set of values which can serve as defaults for estimating the GWP of different sequences of crop rotations including catch crops, grain pea, silage maize, sugar beet, and winter wheat under Central European conditions.