ENERGY INVESTIGATIONS OF DIFFERENT INTENSIVE RAPE SEED ROTATIONS – A GERMAN CASE STUDY - Economics of Sustainable Energy in Agriculture - page 35

4.2 Background of results and critical view on the way of
their presentation

The reduction in energy use for N-fertilisation in the rotations of the
integrated systems had the greatest impact on the results of the first project
period. This reduction was first of all due to the low input crop field beans.
Furthermore a site specific flexible reduction in overall cropping intensity
can be stated (Table 3.5). In the second project period the introduction of
oats into the integrated rotations was most successful in reducing the total
energy input in comparison to 'Conventional'. This crop conserved great
parts of the nitrogen left in the soil by the preceding crop oil seed rape after
harvest with the positive consequence, that the highly energy consuming
N-fertilisation for oats was reduced nearly until zero. Furthermore only
very few pesticides were spread in this crop.
Annual set aside in the fourth year of the crop rotations of the
integrated systems caused further important reductions of the mean area
related energy input They were accompanied by a

considerable reduction in mean energy intensity and - as a

negative aspect - by a reduction in mean energy productivity
of the integrated rotations.
The decision to include the annual set aside into the integrated
rotations was a result of a policy choice. Annual set aside was not essential
for running the integrated farming systems. However, it certainly had
positive ecological effects on the other crops, too. Therefore, it appeared to
be one comprehensive way of analysis to generally include the annual set
aside into the comparisons on rotation level.
Grain units (GU) were used for aggregated considerations of
energy intensity. By this means only, whole rotations could be analysed in
their energy intensity. The impacts of the integrated systems on gross
margins have been the subject of other investigations and thus were
excluded from the argumentation in this chapter (see materials and
methods).

5. CONCLUSIONS

Reductions in production intensity can be better established under good
farming conditions as represented by the location Reinshof . The losses in
productivity observed at Marienstein were higher. The observed negative
impact of annual set aside (Int-a, Int-b resp.) in this context might be
reduced by replacing set aside by a productive crop. The design of the new