Bioenergy from Periodically Waterlogged Cropland in Europe: A First Assessment of the Potential of Five Perennial Energy Crops to Provide Biomass and Their Interactions with Soil

Abstract

Harvesting of silage maize in late autumn on waterlogged soils may result in several ecological problems such as soil compaction and may subsequently be a major threat to soil fertility in Europe. It was hypothesized that perennial energy crops might reduce the vulnerability for soil compaction through earlier harvest dates and improved soil stability. However, the performance of such crops to be grown on soil that are periodically waterlogged and implications for soil chemical and microbial properties are currently an open issue. Within the framework of a two-year pot experiment we investigated the potential of the cup plant (Silphium perfoliatum L.), Jerusalem artichoke (Helianthus tuberosus), giant knotweed (Fallopia japonicum × bohemica), tall wheatgrass (Agropyron elongatum), and reed canary grass (Phalaris arundinacea) for cultivation under periodically waterlogged soil conditions during the winter half year and implications for soil chemical and biological properties. Examined perennial energy crops coped with periodical waterlogging and showed yields 50% to 150% higher than in the control which was never faced with waterlogging. Root formation was similar in waterlogged and non-waterlogged soil layers. Soil chemical and microbial properties clearly responded to different soil moisture treatments. For example, dehydrogenase activity was two to four times higher in the periodically waterlogged treatment compared to the control. Despite waterlogging, aerobic microbial activity was significantly elevated indicating morphological and metabolic adaptation of the perennial crops to withstand waterlogged conditions. Thus, our results reveal first evidence of a site-adapted biomass production on periodical waterlogged soils through the cultivation of perennial energy crops and for intense plant microbe interactions.

Prospects of Bioenergy Cropping Systems for A More Social-Ecologically Sound Bioeconomy

“…Under such conditions, perennial BCS, such as willow short rotation coppice, are suitable options [198]. Recently, several perennial crops were also found to be promising for waterlogged sites [214]. Whereas, these results draw on pot trials and need further evaluation under field conditions.…”

Two Novel Energy Crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L.—State of Knowledge

“…Other authors are more cautious with their statements. Zilverberg et al [86] mentioned that it tolerates moderate flooding while Bauböck et al [87] acknowledged the resistance of S. perfoliatum to water. This observation is supported by Ruf et al [88], who demonstrated that S. perfoliatum not only can withstand waterlogging but benefits from it, doubling the amount of biomass production after waterlogging during the winter period.…”

Jerusalem Artichoke (Helianthus tuberosus L.): A Versatile and Sustainable Crop for Renewable Energy Production in Europe

“…Despite JA can well adapt to dry conditions, the plant has low water use efficiency (WUE) due to its poor stomatal regulation. In a recent study, Ruf et al [33] showed significantly better WUEs in excess soil moisture conditions than in non-excess treatment, for JA plants grown in pots. However, studies conducted in Italy have demonstrated the higher adaptability of this crop to arid environments as compared to other crops such as chicory, kenaf and sweet sorghum [19,21].…”

“…However, in these conditions JA could be cultivated as a perennial crop, targeting to the high stem storage and early tuberization. Even though JA has shown to be tolerant to waterlogging condition [33], excessive soil moisture content has a different negative effect: it reduces plant emergence, increases stalk development, decreases tuber growth and enhances plant vulnerability to pathogens. Overall, fructan yield, tuber size and shape are affected by soil type.…”