Industrial Crops and Products 97 (2017) 653–663 Contents lists available at ScienceDirect Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop Tall wheatgrass (Agropyron elongatum) for biogas production: Crop management more important for biomass and methane yield than grass provenance Michael Dickeduisberg a,∗ , Harald Laser b , Bettina Tonn a , Johannes Isselstein a a Department of Crop Sciences, University of Göttingen, Von-Siebold-Strasse 8, 37075 Göttingen, Germany b South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494 Soest, Germany a r t i c l e i n f o Article history: Received 24 October 2016 Received in revised form 27 December 2016 Accepted 28 December 2016 Keywords: Tall wheatgrass Cutting frequency Cutting height NIRS Anaerobic digestion Growing degree days a b s t r a c t Tall wheatgrass (Agropyron elongatum) has been proposed as a new energy crop of a dry matter yield (DMY) and methane hectare yield (MHY) potential similar to maize. So far, little is known about the agronomy of the grass for biogas production in temperate Europe. In a field trial the hypothesis was tested that aboveground DMY and MHY are affected by the frequency of cutting and cutting height, and that these management effects interact with the tall wheatgrass germplasm. Four wheatgrass provenances were sown in a three-factorial block design with three cutting heights at harvest (5, 10, and 15 cm above soil surface) and three levels of cutting frequency (one, two, and four cuts year −1 ). Aboveground DMY (two full harvest years), crude nutrient and fibre content as well as the specific methane yield (SMY, one full harvest year) and MHY were determined. In general, only small differences in the target variables among the different provenances were found. Likewise, a significant interaction of provenance x crop management was only found for the DMY in the second year. The cutting frequency strongly affected the DMY with a two-year average of 14.6, 18.4, and 14.9 t DM ha −1 and the MHY of 3505, 5705, and 5384 Nm 3 methane ha −1 for the one-, two-, and four-cut regime, respectively. The cutting height was less important with DMY values of 17.2, 16.3, and 14.4 t DM ha −1 for 5, 10, and 15 cm cutting height, respectively. SMY was well predictable from growing degree days. In conclusion for Central European conditions the performance of tall wheatgrass is suitable for biogas production and clearly responds to cutting frequency and cutting height with highest DMY and MHY in the two–cut system and 5–10 cm cutting height. The choice of the wheatgrass germplasm was less important. It remains to be shown for how long tall wheatgrass stands will maintain their performance. © 2017 Elsevier B.V. All rights reserved. 1. Introduction During the last decade maize has become the most important feedstock for the increasing number of biogas plants in Germany (Dahlhoff, 2013). In several regions it is now the dominant crop in agricultural systems. As a consequence, public concerns over the sustainability of biogas production have risen because the increas- ing acreage of maize is linked to increasing pest pressure, high soil Abbreviations: DM, dry matter; DMY, dry matter yield; HBT, Hohenheim Biogas Yield Test; MHY, methane hectare yield; Nm 3 , standard cubic meter; oDM, organic dry matter; SMY, specific methane yield. ∗ Corresponding author. Present address: Center of Renewable Resources, Cham- ber of Agriculture for North Rhine-Westphalia, Haus Düsse, 59505 Bad Sassendorf, Germany. E-mail address: michael.dickeduisberg@lwk.nrw.de (M. Dickeduisberg). erosion, nutrient losses and biodiversity decrease (Herbes et al., 2014; Schittenhelm et al., 2011). The predicted climate change with a precipitation shift from summer to winter months and an increased frequency of summer droughts (Zebisch et al., 2005), fur- ther calls for alternative bioenergy crops. Tall wheatgrass (Agropyron elongatum (Host) P. Beauv.) has been proposed as an alternative crop to maize. It is considered to be drought tolerant (Moore et al., 2006) and it is a representative for perennial crops with little erosion risk (Pimentel et al., 1987) and small nutrient losses (Dinnes et al., 2002). As it is a new crop to tem- perate Europe the pressure of pests and diseases is likely to be small. In addition, replacing maize to some extent with tall wheatgrass would contribute to the diversification of crop rotations, which is a goal of the EU Common Agricultural Policy (European Parliament, 2013). Preliminary studies in Germany have demonstrated the yield potential of tall wheatgrass with dry matter yield (DMY) compara- ble to maize (Heinz, 2015). Apart from DMY the specific methane http://dx.doi.org/10.1016/j.indcrop.2016.12.055 0926-6690/© 2017 Elsevier B.V. All rights reserved.