Soil quality indicator response to land‐use change from annual to perennial bioenergy cropping systems in Germany

Abstract

Production of biomass feedstock for methanation in Europe has focused on silages of maize and cereals. As ecological awareness has increased in the last several years, more attention is being focused on perennial energy crops (PECs). Studies of specific PECs have shown that their cultivation may enhance agrobiodiversity and increase soil organic carbon stocks while simultaneously providing valuable feedstock for methanation. This study was designed to compare soil quality indicators under annual energy crops (AECs), PECs and permanent grassland (PGL) on the landscape level in south-western Germany. At a total 25 study sites, covering a wide range of parent materials, the cropping systems were found adjacent to each other. Stands were commercially managed, and PECs included different species such as the Cup Plant, Tall Wheatgrass, Giant Knotweed, Miscanthus, Virginia Mallow and Reed Canary Grass. Soil sampling was carried out for the upper 20 cm of soil. Several soil quality indicators, including soil organic carbon (C org ), soil microbial biomass (C mic ), and aggregate stability, showed that PECs were intermediate between AEC and PGL systems. At landscape level, mean C org content for (on average) 6.1-year-old stands of PEC was 22.37 (AE7.53) g kg À1, compared to 19.23 (AE8.08) and 32.08 (AE10.11) for AEC and PGL. C mic contents were higher in PECs (356 AE 241 lg C g À1 ) compared to AECs (291 AE 145) but significantly lower than under PGL (753 AE 417). The aggregate stability increased by almost 65% in PECs compared to AEC but was still 57% lower than in PGL. Indicator differences among cropping systems were more pronounced when inherent differences in the parent material were accounted for in the comparisons. Overall, these results suggest that the cultivation of PECs has positive effects on soil quality indicators. Thus, PECs may offer potential to make the production of biomass feedstock more sustainable.

How to Generate Yield in the First Year—A Three-Year Experiment on Miscanthus (Miscanthus × giganteus (Greef et Deuter)) Establishment under Maize (Zea mays L.)

“…This makes the intercropping establishment MUM more profitable than REF, in particular due to the avoidance of a missing yield in the first year of establishment. Consequently, MUM combines advantages of both maize and miscanthus: high yields of maize [41] and ecosystem services of miscanthus [17,[60][61][62] from the second year onwards. Farmers could generate a notable income to compensate at least some of the high establishment costs arising in the establishment year [30].…”

“…The accumulated DMY over the three years was 31.7 Mg ha −1 for MUM, of which 10.1 Mg ha −1 were miscanthus-based, compared to 17.7 Mg ha −1 for REF.These results indicate that miscanthus establishment under maize could compensate for its lack of yield in the first year.in Europe to be as high as 11.11 million ha. Consequently, miscanthus can be considered a promising industrial crop, both in terms of climate change adaptation and mitigation, and also for the provision of a more environmentally benign biomass supply for a growing bioeconomy [6,[15][16][17][18].Miscanthus utilization options include combustion, anaerobic digestion, bioethanol production, building material and animal bedding [1,[19][20][21]. Harvesting times should be adjusted according to utilization pathway chosen.…”

“…in Europe to be as high as 11.11 million ha. Consequently, miscanthus can be considered a promising industrial crop, both in terms of climate change adaptation and mitigation, and also for the provision of a more environmentally benign biomass supply for a growing bioeconomy [6,[15][16][17][18].…”

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

“…Recently, perennial energy crops (PECs) have been introduced as promising alternatives for biomass production. They are likely to enhance agrobiodiversity, may reduce soil surface runoff and vulnerability for soil erosion, presumably improve groundwater quality and were proven to sequester carbon in soil [9][10][11][12][13][14][15]. However, in terms of methane yields per hectare they cannot entirely compete with silage maize.…”

The possibility of using sewage sludge for energy crop cultivation exemplified by reed canary grass and giant miscanthus

“…Scientific literature suggests that the use of sewage sludge in cultivation of energy crops increases soil biological activity (Ruf et al 2018). The increased soil enzymatic activity confirms that, as a result of mineralization of organic matter, sewage sludge makes macronutrients available to plants (Joniec 2018).…”