Evaluating Bioenergy Cropping Systems towards Productivity and Resource Use Efficiencies: An Analysis Based on Field Experiments and Simulation Modelling

Abstract

Silage maize (Zea mays L.) is the dominating energy crop for biogas production due to its high biomass yield potential, but alternatives are currently being discussed to avoid environmental problems arising from maize grown continuously. This study evaluates the productivity and resource use efficiency of different bioenergy crops and cropping systems using experimental and simulation modelling derived data. The field experiment consisted of two years, two sites differing in soil texture and soil water availability, different cropping systems and increasing nitrogen (N) supply. Continuous (two years) perennial ryegrass and two crop rotations including winter cover crops (double cropping system) and combining C4 and C3 crops were compared with continuous maize (maize-maize). The productivity of the crops and cropping systems in terms of dry matter (DM) yield was analyzed with respect to the fraction of light interception and light use efficiency (LUE). In addition, water use and water use efficiency (WUE), N uptake, and N use efficiency (NUE) were quantified. DM yield of the double cropping system was similar to that of continuous maize, due to a prolonged leaf area duration, compensating for the intrinsic lower LUE of C3 crops. Perennial ryegrass was less productive than the other crops/cropping systems. Nitrogen uptake and consequently N demand of perennial ryegrass and the C3 crops of the crop rotations were higher than for maize-maize. Groundwater recharge was mainly site-dependent, but was at both sites higher for maize than for the crop rotations or the perennial ryegrass system. Our results indicate that, in terms of biomass productivity, optimized rotations are feasible alternatives to maize-maize, but trade-offs exist in terms of water and N use efficiency.

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

“…(1) crop rotations [76,[125][126][127][128], (2) the intercropping of annual or perennial crops with legumes [86,[129][130][131][132], (3) the establishment of winter-annual species such as camelina (Camelina sativa L. Crantz) or perennial rye under annual crops [133][134][135], and (4) under maize-establishment of perennial energy crops such as miscanthus [115], the cup plant [136], and wild plant mixtures [122] among others [76,108,123].…”

Green, Yellow, and Woody Biomass Supply-Chain Management: A Review

“…In [20], multiple-production systems were also evaluated by developing and implementing a comparative computational tool potentially applied to any set of given crops, given energy-related or production-related input, and according to any specific production practices. A study that refers to different bioenergy cropping systems is presented by [21]. They evaluated the productivity of selected systems by using experimental data that were further analyzed by a simulation tool to identify potential limitations of resource-use efficiency on biomass dry matter yield.…”