Effects of first‐ and second‐generation bioenergy crops on soil processes and legacy effects on a subsequent crop

Abstract

To develop a more sustainable bio-based economy, an increasing amount of carbon for industrial applications and biofuel will be obtained from bioenergy crops. This may result in intensified land use and potential conflicts with other ecosystem services provided by soil, such as control of greenhouse gas emissions, carbon sequestration, and nutrient dynamics. A growing number of studies examine how bioenergy crops influence carbon and nitrogen cycling. Few studies, however, have combined such assessments with analysing both the immediate effects on the provisioning of soil ecosystem services as well as the legacy effects for subsequent crops in the rotation. Here, we present results from field and laboratory experiments on effects of a standard first-generation bioenergy crop (maize) and three different second-generation bioenergy crops (willow short rotation coppice (SRC), Miscanthus 9 giganteus, switchgrass) on key soil quality parameters: soil structure, organic matter, biodiversity and growth and disease susceptibility of a major follow-up crop, wheat (Triticum aestivum). We analysed a 6-year field experiment and show that willow SRC, Miscanthus, and maize maintained a high yield over this period. Soil quality parameters and legacy effects of Miscanthus and switchgrass were similar or performed worse than maize. In contrast, willow SRC enhanced soil organic carbon concentration (0-5 cm), soil fertility, and soil biodiversity in the upper soil layer when compared to maize. In a greenhouse experiment, wheat grown in willow soil had higher biomass production than when grown in maize or Miscanthus soil and exhibited no growth reduction in response to introduction of a soil-borne (Rhizoctonia solani) or a leaf pathogen (Mycosphaerella graminicola). We conclude that the choice of bioenergy crops can greatly influence provisioning of soil ecosystem services and legacy effects in soil. Our results imply that bioenergy crops with specific traits might even enhance ecosystem properties through positive legacy effects.

Impact of newly introduced perennial bioenergy crops on soil quality parameters at three different locations in W‐Germany

“…Crop treatment N-res C-to-N-res N-soil C-to-N-soil N-mic Nitrification Soils under perennial crops tend to store more SOC than annual crops do (Culman et al, 2010;Felten and Emmerling, 2012). This may be attributed to higher amounts of plant resi-dues after harvest or a higher lignin content of PEC residues (Schrama et al, 2016). Changes in SOC due to perennial crop cultivation depend mostly on crop type, management, and previous land-use history (Fargione et al, 2008).…”

“…However, to date, little information is available on the impact that these newly introduced perennial bioenergy crops have on soil quality determining properties ( Doran and Parkin , ; Anderson‐Teixeira et al, ; Don et al, ; Harris et al, ; Chimento et al, ), such as the amounts of soil organic C and N, soil biological properties, and aggregate stability. Perennial grasses, such as switchgrass and reed canary grass, may positively affect key soil quality parameters such as soil organic carbon (SOC) ( Liebig et al, ; Harris et al, ; Ferschaud Chimento et al, ), reduce soil erosion and promote wildlife habitats ( Schrama et al, ). Moreover, beneficial insects (arthropods) responded positively to the increased vegetational diversity of switchgrass sites ( Gardiner et al, ).…”

Environmental Performance of Miscanthus, Switchgrass and Maize: Can C4 Perennials Increase the Sustainability of Biogas Production?

“…For this reason, replacing biogas maize with miscanthus or switchgrass could positively affect the biodiversity by adding novel, perennial crops to the agricultural landscapes. However, it should be noted that the impact on soil biodiversity may be influenced by the choice of the perennial biomass crop [60]. Furthermore, both perennials can be characterized by their comparatively low-input crop management, after their successful establishment in year one.…”

Introducing Miscanthus to the greening measures of the EU Common Agricultural Policy

“…Schneckenberger & Kuzyakov () concluded that the carbon accumulation in soil under Miscanthus was similar to that under permanent grassland. The potential of C storage in addition to no‐till cultivation and less plant nutrition and protection (which in practice is carried out in the first 2–3 years) may also positively affect soil stability, that is aggregate stability, and thus, potential soil erodibility (McCalmont et al ., ; Schrama et al ., ). Specifically, soil quality was significantly improved through the conversion for example of maize monoculture to perennial second generation (2G) bioenergy crops, for example SRC, Miscanthus , switchgrass and giant reed (Chimento et al ., ).…”

“…Many studies on Miscanthus and other perennial 2G bioenergy crops reported positive effects on species and habitat diversity, when they replace arable land use, but this strongly depends on the respective field‐scale management (Bellamy et al ., ; Dauber et al ., ; Sage et al ., ; Baum et al ., ; Schrama et al ., ). According to Jodl et al .…”