Is the Increasing Bio-methane Production the Sole Reason for the Declining Grassland Area in Germany? An Analysis of Geo-referenced Land Use Data

Abstract

In the last years the area used as permanent grassland declined considerably in Germany. This decline raised public concerns as grassland produces more environmental benefits compared to arable land. In the public debate the loss of grassland is frequently linked to the promotion of silage maize as feedstock for bio-methane production via the renewable energy law. We present a geo information system, which is capable to process various high resolution data on land use, land use change and site conditions. With the help of the system we analyse whether the expansion of bio-methane production is the primary reason for the observed land use change in the period 1999–2007. We provide results for Germany as a whole. These general results are supplemented by an analysis conducted for the federal state of Lower Saxony (2005–2007). This state is a stronghold of the bio-methane production and more detailed data are available. Our results show, that feedstock for the production of bio-methane is primarily cultivated on existing arable land. Farms growing feedstock for bio-methane production have a higher probability to convert grassland to arable land though these farms cultivate only very few areas of former grassland. The probability of grassland conversion increases with the vicinity of biogas plants. However, most of the conversion can be attributed to dairy farms without the cultivation of feedstock for bio-methane production. Generally, the likelihood that grassland is converted increases markedly if the managing farmer changes. Based on our findings we discuss different options to protect permanent grassland. We argue that our conclusions do also apply to the general context of limiting undesired direct and indirect land use change.