Yield and quality development comparison between miscanthus and switchgrass over a period of 10 years Y. Iqbal a, * , M. Gauder b , W. Claupein b , S. Graeff-H € onninger b , I. Lewandowski a a University of Hohenheim, Biobased Products and Energy Crops (340b), Fruwirthstraße 23, 70599 Stuttgart, Germany b University of Hohenheim, Department of Agronomy (340a), Fruwirthstraße 23, 70599 Stuttgart, Germany article info Article history: Received 7 July 2014 Received in revised form 21 May 2015 Accepted 23 May 2015 Available online xxx Keywords: Miscanthus Switchgrass Harvest date N fertilization LCA (life cycle assessment) Combustion abstract The establishment of perennial crops has emerged as a very viable option for biomass-based energy production mainly due to their comparative ecological advantages over annual energy crops. This study is based on data collected from a field trial between 2002 and 2012 and was carried out with the main objective of evaluating the yield and quality performance of miscanthus and switchgrass using different harvest dates and N fertilization regimes (0 kg, 40 kg, 80 kg). Over the whole plantation period (including three years of establishment period), the mean yield of miscanthus was 16.2 t DM ha 1 a 1 , while switchgrass yielded 10.2 t DM ha 1 a 1 . In miscanthus, each increase in fertilizer level increased the N content in the harvested biomass, whereas in switchgrass, no significant difference was recorded for 0 kg and 40 kg N levels. The effect of N fertilization on ash was significant but independent of the crop. Both miscanthus and switchgrass biomass samples from the late harvests had a significantly lower N content than those from the early harvests. A Life Cycle Assessment covering the conducted field work and inputs of this trial showed relatively low energy input and emissions connected to the cropping of miscanthus. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction In the last decade, policy support and biofuel-driven mandates have led to a significant increase in the production of dedicated energy crops in Europe and America. However, criticism of the production of food and feed crops grown especially for energy purposes, such as maize or rapeseed, has motivated the search for high-yielding non-food energy crops. In recent years, the estab- lishment of perennial crops has emerged as a very viable option mainly due to their comparative ecological advantages over annual energy crops [27,28,32]. Among these, the C4 grasses miscanthus and switchgrass combine the potential to deliver high biomass yield and ability to grow under a wide range of climatic conditions [21]. Miscanthus is characterized by a high dry matter yield potential [6], and can be grown without any pest or weed control measures once the crop is established [24]. However, because there is pres- ently only one commercially available clone, Miscanthus x gigan- teus, it has some limitations such as a lack of winter hardiness during the establishment period [21]. Additionally M. x giganteus needs to be propagated vegetatively resulting in high plantation costs [3]. Contrary to this, switchgrass can be established via seeds and the lower production costs make it a more practical option among the energy crops [26]. However, the biomass yield potential of switchgrass is considered to be lower than that of miscanthus [21]. Miscanthus and switchgrass can be cultivated on marginal soils (mainly low fertile) due to their low nutrient requirements and high net primary production potential [31]. The low nutrient re- quirements of miscanthus in particular [8] are accommodated by its well-developed rooting system [27] and the relocation of nutrients back to rhizomes at the end of the growth season. The annual dry matter yield production potential of the aforementioned C4 perennial crops is 10e20 t ha 1 in temperate climates [36]. Under optimal growth conditions however, the yield can be higher than 30 t ha 1 [27]. The productivity can be further improved by the optimized combination of management practices, such as the appropriate N fertilization rate [1] and choice of appropriate har- vest time [24]. However, improvement in yield through various management practices can, over time, affect the composition of the produced biomass and subsequently the thermo-chemical con- version processes for energy production. * Corresponding author. Tel.: þ49 711 45922379. E-mail address: Iqbal_Yasir@uni-hohenheim.de (Y. Iqbal). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2015.05.134 0360-5442/© 2015 Elsevier Ltd. All rights reserved. Energy xxx (2015) 1e9 Please cite this article in press as: Iqbal Y, et al., Yield and quality development comparison between miscanthus and switchgrass over a period of 10 years, Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.134