Perennial Energy Crops Research Articles

Modelling the impact of business risk on the competitiveness of purpose-grown biomass of annual and perennial crops

Perennial energy crops compete with conventional annual crops in land-use. The production price of biomass from perennial energy crops is thus derived on the basis of the opportunity cost principle. This means that in deciding whether to grow perennial energy crops, the farmer will demand a price for biomass that will at least provide him with the same economic effect over the lifetime of the plantation in the form of the present value of net cash flows over the lifetime of the energy crop plantation. The level of discounts used to discount the cash flows associated with (annual) conventional crops and perennial energy crops plays an important role in modelling the biomass production price. The business risk associated with the two types of crops is different, with generally higher risk associated with perennial energy crops. This study focuses on developing a methodology to incorporate the risk associated with growing conventional and energy crops and to derive the discount rate for both crop groups. The methodology is demonstrated using the example of the Czech Republic and the price level in 2021. The analysis using Czech data led to a discount rate of 8.5 % for conventional crops and 11.5 % for perennial energy crops. The increase in the discount value for perennial energy crops leads to an increase in the expected biomass sales price by a producer. The sensitivity of the biomass production price level to an increase in the discount rate is lower for Miscanthus plantations compared to short rotation coppice.

An assessment of policies to promote perennial energy crop and woodland planting

If the UK is to meet its target of reducing greenhouse gas (GHG) emissions to net zero by 2050, significant land-use change will be required. More woodland will have to be created and more perennial energy crops (PECs) will need to be grown. Land will also be required for food production, habitat restoration, and for new settlements. Government intervention will be required if landowners are to deliver this transition in land use. This research identified 43 policies that had been proposed for delivering increased planting of PECs and new woodlands. Their desirability, feasibility and potential effectiveness were assessed by a panel of experts using a policy Delphi method. Results showed that the most important was a comprehensive land-use policy, which will have to be delivered by the post-Brexit, Environmental Land Management (ELM) scheme in the UK. PEC cultivation could be most effectively encouraged by delivering investment or incentives to electricity generators at the top of the supply chain. Woodland creation requires support from attractive, well-administered grants to replace annual farm income. Educational and informational policies are also needed to breakdown the divisions between the farming and forestry sectors, and to overcome reluctance of landowners and farmers to grow non-food crops.

Earthworm communities and their relation to above‐ground organic residues and water infiltration in perennial cup plant (Silphium perfoliatum) and annual silage maize (Zea mays) energy plants

AbstractPerennial energy cropping systems are hailed as a sustainable way of mitigating and potentially adapting to climate change. As a result of the absence of tillage, soils cropped with perennials like cup plant (Silphium perfoliatum) promote abundant and functionally diverse earthworm communities. Hence, ecosystem service provision because of earthworm activity and functional redundancy, for example, litter decomposition, water infiltration and nutrient turnover, is considerably enhanced in perennial cropping systems. We studied the abundance and functional role of earthworms in non‐tilled perennial systems and reduced‐tilled annual systems to assess their relationship with the respective above‐ground organic residues and their implications for the soil water dynamic. We sampled earthworms and simultaneously measured the saturated infiltration rate for two consecutive years in cup plant and maize (Zea mays) fields. Furthermore, we sampled above‐ground litter each trimester in both systems and analysed the total C and N content and CN ratios. Our field investigations revealed significantly higher earthworm abundance, species diversity and richness in cup plant systems likely because of the absence of tillage and the formation of a litter layer. High abundances of juveniles in both maize and cup plant systems pointed to harsh habitat conditions likely because of temperature variations, waterlogging and bulk density. The respective field litter was of minor importance as a food source in both systems because of poor quality, but may positively affect the soil water balance in cup plant systems. Earthworm populations in maize may have been supported by organic fertilizer while earthworm populations in cup plants may have additionally benefitted from the extensive root network and a higher on‐site plant diversity. Reduced tillage regimes in maize systems may have enhanced saturated infiltration rates. A direct link between earthworms and infiltration was not validated, but may not be excluded in the future, as earthworm populations may develop slowly because of adverse habitat conditions. Our results show that perennials support abundant and diverse earthworm populations and indicate the importance of functional redundancy and the diversity of food sources. The combination of both earthworm abundance and perennial cropping systems is capable of increasing on‐site ecosystem stability and supporting adaptation to climate change by increasing functional redundancy and, ultimately, providing ecosystem services. The noticeable occurrence of the latter, however, may be delayed because of the slow establishment of earthworm communities and delayed build‐up of ecosystems stability. Hence, a transitional phase is inevitable to reap the benefits of perennial energy cropping systems and must be accounted for.

Towards a sustainable energy future: Evaluating Arundo donax L. in continuous anaerobic digestion for biogas production

AbstractIn response to the EU's REPowerEU initiative (COM (2022) 108) which encourages an increase in biogas production by 20% in member states by 2030 to boost energy independence, it has become essential to identify sustainable alternatives to traditional feedstocks for biogas production, especially in the EU Member states where there is still high dependence on corn silage as the main raw material in biogas plants. While corn silage, predominantly used in the European biogas plants today, serves primarily for the livestock sector, alternative sources need to be explored. Therefore, this study aimed to evaluate the potential of Arundo donax, a perennial energy crop, as an alternative feedstock in a continuous anaerobic process. The biogas yield and its quality, characterized by CH4, CO2, H2S and O2 content, were determined during a continuous process with A. donax, compared with two mixed feedstocks of A. donax and corn silage over a 5‐month period in a continuous anaerobic digestion process. The results revealed that A. donax exhibits a biogas yield and methane content comparable to corn silage, indicating its potential as a viable and sustainable alternative feedstock for biogas production.

Converting an Established Sida hermaphrodita Field into Arable Farming

The long-term performance of perennial energy crops and their elimination is important for long-term planning and use of agricultural land. In this study, the elimination of a six-year-old Sida hermaphrodita (hereafter referred to as Sida) stock for agricultural reclamation was investigated over three years. Crop rotation using maize, winter wheat, and sugar beet, a catch crop, as well as mechanical–chemical treatments were employed according to agricultural practices. After soil grubbing at the beginning of the experiment and prior to further treatments, on half of the former Sida planting area, visible Sida roots were manually removed in addition to determining their potential effect on total resprouting. Prior to each crop harvest, resprouted Sida plants were counted. At harvest, by the end of the first year, 476 versus 390 resprouted Sida plants were found in the investigated areas of 315 m2 each, where preceding manual root removal either took place or not, respectively. This accounted for 76% and 62% of the initial Sida planted. In the second year, the overall number of resprouted Sida declined significantly, accounting for 15 and 11 plants (i.e., 2.4% and 1.8% of initially planted), and in the third year, only two and four residual plants (i.e., 0.3% and 0.6%) were found, representing an almost 100% Sida elimination rate. We conclude that additional root removal did not result in a significant difference in Sida regrowth compared to the mechanical–chemical treatments only. No impediments to harvesting and no loss of yield in any crops were observed due to resprouted Sida in the existing field crops. No Sida plants were found outside the initial field, indicating a low dispersion potential and invasiveness. The results show that successful recultivation of an established Sida stock is possible through common agricultural practices and that resprouting Sida plants did not negatively affect the subsequent crops.

Energy Costs and Greenhouse Gas Emissions of Giant Reed (Arundo donax L.) Production for Use as a Bioenergy Vector

This study estimates the energy costs and greenhouse gas emissions for the production and the processing for thermal use of Giant reed ( Arundo donax L.), a second-generation perennial energy crop. The agronomic study took place in Buenos Aires (Argentina) under humid to subhumid climatic conditions. Rhizomes and in vitro micropropagated plantlets were employed and cultivated under both fertilization and rainfed conditions during 2018–2022. The yield demonstrated a substantial increase from 3.8 t/ha to 23.1 t/ha from implantation to crop setting. Throughout this period, the energy input escalated from 23 to 70 GJ/ha, with the planting phase exhibiting the highest energy intensity. This surge can be attributed to the use of herbicides, accounting for 44.1%–61.3% of the energy consumed. Energy outputs were 17 (±0.19) MJ/kg as the low heating value obtained from the biomass elemental composition. The net energy yield for the 10-year lifecycle resulted in 2851.3 (±20.2) GJ/ha, and the output/input ratio varied from 41 (for pellets) to 126 (for chips). Carbon emissions ranged from 343.9 (for plantlets) to 371.9 (for rhizomes) kg CO2e/ha during the implantation stage, resulting in 208.3, 397.6, and 859.6 kg CO2e/ha for chips, bales, and pellets, respectively. This study reinforced the knowledge about the farming of this energy crop and displayed a promising scenario for the sustainable development of the Arundo donax L. based value chain. JEL Classification Q4, Q43, Q56

The factors determining uptake of energy crop cultivation and woodland creation in England: Insights from farmers and landowners

Perennial energy crops (PECs) and trees have key roles to play in delivering the negative emissions needed for the UK to reduce greenhouse gas emissions to net zero by 2050. Significant changes to land use are needed and the decision to make changes will lie with individual landowners. Using in-depth, semi-structured interviews, this research explores the attitudes of farmers and landowners in England to replacing traditional arable and livestock farming with growing annual or perennial energy crops or planting trees. It was concluded that considerable government policy intervention will be needed to overcome the many economic and social barriers in place including lack of markets and attractive contracts for growers, high establishment costs, loss of annual income, high prices available for cereal crops and the cultural division between farming and forestry. Although energy crops and woodland creation are generally researched and regulated separately, this research suggests that annual energy crops, PECs and woodland creation form a spectrum of land use options for a landowner, with the propensity to adopt these crops being determined predominantly by crop attributes including the risk of planting and the term of commitment.

Effects of Selected Annual and Perennial Energy Crops on Lumbricidae Community Assemblages

Effects of Selected Annual and Perennial Energy Crops on Lumbricidae Community Assemblages

Complex aspects of climate change impacts on the cultivation of perennial energy crops in the Czech Republic

Perennial energy crops, called also second-generation energy crops, can make a significant contribution to the renewable energy balance in Central European, land locked regions, in the future. When estimating the biomass potential of energy crops, possible impacts of ongoing climate change must be considered. Climate change in Central European conditions will result in an increase in average temperatures and especially in the amount and distribution of precipitation. This will be reflected in a change in the type of climate region assigned to each land plot. Climate change leads to a change in growing conditions, a change in yields of conventional and energy crops and to a change in the allocation of energy crops to land in the region. Analysis of production data from long-term field experiments shows that the varieties of second-generation energy crops are and will be capable of adapting to the current effects of climate change over the next two decades. Modelling of biomass potential in a GIS environment shows that climate change will result in a change in land allocation between short rotation coppice and Miscanthus. The manner in which land is selected for energy crops has a significant impact on biomass potential from second generation energy crop. The paper presents a methodology for estimating the impact of climate change on the biomass potential of perennial energy crops using the Czech Republic as an example.

The efficiency and stability of soil organic carbon sequestration by perennial energy crops cultivation on marginal land depended on root traits

The sustainability of bioenergy cropping systems hinges on the dynamics of soil organic carbon (SOC). Switchgrass and Miscanthus, as the two leading perennial energy crops, have been extensively cultivated on marginal land for bioenergy production. However, the effects of their cultivation on SOC sequestration and its underlying mechanisms remain unclear. Herein, we quantified the contributions of plant– and microbial–derived C to SOC accumulation by tracing 13C natural abundance and amino sugars on switchgrass- and Miscanthus-planted lands (i.e. belongs to poor acidic red soil) experienced 10 years of C3–C4 vegetation conversion. The results showed Miscanthus cultivation induced an approximately 6.3 times greater improvement in SOC compared to switchgrass. However, the organic C stability in Miscanthus-planted soil was comparatively lower than that of switchgrass. This was consistent with our global meta-analysis, whereby Miscanthus and switchgrass cultivation were observed to increase SOC by 16.0% and 7.1%, respectively. Miscanthus–cultivated soil was more replenished by plant–derived C stored in particulate organic C, owing to the greater biomass and lower root quality (reflected by the high ratio of lignin to nitrogen). In contrast, switchgrass–cultivated soil was enriched with more microbial–derived C, as its greater root quality induced a more efficient C utilization by the microbes. This was preferentially associated with the soil minerals. In conclusion, perennial energy crops cultivation on marginal land substantially enhances SOC sequestration, whereas the stability of SOC is dependent on the root traits.

Spatial Differentiation of Agricultural Biomass Potential in Polish Voivodeships

The main aim of the article is to assess the potential of agricultural biomass and the possibility of its use for energy purposes in Polish voivodeships. Five sources of agricultural biomass were analyzed: straw, hay, waste wood from orchards, perennial energy crops, and natural fertilizers. For the purposes of the research, the theoretical and technical potential of agricultural biomass was estimated. The potential of agricultural biomass was estimated for Polish voivodeships based on the data of the 2020 Agricultural Census. The conducted research shows that Polish voivodeships have a significant theoretical potential for agricultural biomass. However, due to the fact that biomass is widely used in plant production (as a natural fertilizer) and animal production (as fodder or bedding), only about 40% of the identified theoretical potential can be used for energy purposes. The research also shows that the dominant source of agricultural biomass that can be used in Poland is straw from cereal crops. Moreover, a significant part of the identified potential is located in the western part of Poland (Wielkopolskie, Dolnośląskie, Kujawsko-Pomorskie, Zachodniopomorskie voivodships) and partly in the east (Lubelskie voivodship). Although the possibility of using natural fertilizers for energy purposes has not been identified, the theoretical potential of which is very high, an increase in the importance of renewable energy from agricultural biogas plants should be expected in the near future. This is due to the changes taking place in the storage and management of natural fertilizers.

A Spatially Explicit Evaluation of the Economic Performance of a Perennial Energy Crop on the Marginal Land of the Loess Plateau and China

The Loess Plateau, with a large area of marginal land, holds the potential to produce 62–106 Tg per year of switchgrass biomass; however, the economic feasibility of producing bioenergy in the region is unclear. The farm-gate feedstock production (FGFP) cost of switchgrass was calculated in a spatially explicit way by taking the geographic variation in crop yield, soil properties, land quality, and input costs into consideration in order to evaluate the economic performance of bioenergy production. Cost–supply curves were constructed to explore the energy supply potential of switchgrass feedstock. The calculations were conducted using ArcGIS in a 1 km grid and all the evaluations were conducted under different agricultural management practice (AMP) scenarios in parallel. The FGFP costs showed significant spatial variation ranging from 95 to 7373 CNY (Chinese Yuan) per tonne−1 and that the most economically desirable areas are scattered in the south and southeast region. The weighted average FGFP costs are 710, 1125, and 1596 CNY per tonne−1 for small bale (SB), large bale (LB), and chipping (CP) harvest methods, respectively. The projected energy supply potential is 1927 PJ (Petajoules) per year−1, of which 30–93% can be supplied below the market prices of different fossil fuels according to feedstock formats. Compared to current biomass residual pricing, 50–66 Tg (Teragrams) switchgrass feedstock is competitive. The results demonstrated that the Loess Plateau holds the potential to produce bioenergy that is economically feasible. This study provides a methodological framework for spatially explicit evaluation of the economic performance of perennial energy crops. Detailed information obtained from this study can be used to select the optimal locations and AMPs to produce feedstock production at minimum cost.

Nematode abundances and community diversity under energy crop (maize and sainfoin) cultivation in annual and perennial cropping systems

Despite conservation efforts and increased awareness, the loss of soil biodiversity goes on across a wide range of ecosystems. Since soil function and structure depend mainly on the state of the biological communities, the soil quality assessment and disturbance in annual vs. perennial cropping systems is done with the help of indicators such as nematodes. Agricultural practices like mix cropping causes variations in the taxonomic abundance of soil nematode communities. This field experiment aimed to assess the overall effect of annual and perennial energy crops (maize: Zea mays and sainfoin: Onobrychis viciifolia) on the nematode communities under pure and mixed cultivation. Sainfoin had the highest nematode abundance, followed by the mixed culture and maize. Out of 38 identified genera, 19 were identified under maize, 31 under perennial sainfoin, 28 under annual sainfoin, 28 under perennial mixture, 20 under the annual mixture and 13 co-existed among these treatments. Of all the trophic groups, the bacterivores were the most abundant (738), followed by plant-parasitic nematodes (272), omnivores (230), fungivores (84), and carnivores (33). Nematode abundance was lower under the annual than perennial plots of both sainfoin and the mixed culture. The perennial plots were dominated by plant-parasitic nematodes. Our results support the idea that soil nematodes should be considered for inclusion in indices of soil quality through their contribution to soil processes. Also, soil nematodes and energy crops like sainfoin may increase the functional properties of agricultural ecosystems and allow better productivity and sustainability.

Spatial cost analysis for switchgrass cultivation: Case of Eskisehir

Switchgrass (Panicum virgatum L.) is a highly drought-resistant and cold-tolerant perennial energy crop, promising a favourable biomass energy source lately. For cost-effective switchgrass cultivation, physical characteristics and cost factors are critical in encouraging decision-makers to invest in this field. This study aims to develop a methodology to place cost analyses on a spatial basis and relate them with the environmental factors in the Eskisehir province, Türkiye. The results of a former study presenting the suitable lands for switchgrass cultivation in the region, in terms of physical parameters, were used to perform the spatial cost analysis based on the so-called indirect factors, fuel consumption, and crop yield. Regarding the assumed yield amounts and fuel consumption, the findings revealed that switchgrass agriculture on suitable lands would not promise a fixed profitability rate or fixed dry product sales price. Hence, different dry product sales prices were spatially determined and mapped according to five profitability ratios. The sales prices of the dry crop produced from high-suitable agricultural lands were found to be competitive (26.24 USD, 26.28 USD, and 26.31 USD) under free market conditions. Profitability rates varied between 22.79% and 22.66% with an optimistic scenario. It is predicted that 124,680 tons of bioethanol can be obtained with switchgrass production on lands where maximum benefit is provided. The method presented in this study demonstrates that a suitable site selection process can be conducted more holistically when cost-affecting parameters are integrated into spatial analyses and layering processes.

Assessment of Energy–Economy and Environmental Performance of Perennial Crops in Terms of Biogas Production

Biogas production plays an important role in the clean energy economy and is reducing the problems of the energy crisis. The main objective of the current study is to analyze environmental performance by using perennial energy crops in the agricultural sector. Perennial energy crops are neutral for carbon and can be used for electricity and heating, which may mitigate climate change as well. The purpose of this work was to investigate and compare the energy–economy effectiveness and environmental performance of the suitability of four perennial crops for biogas production. Environmental performance was analyzed using the method of the life cycle assessment. To identify the most environmentally sustainable perennial crops for biogas production, a comparative analysis was conducted on four different crops: Lucerne, Miscanthus, Switchgrass, and Reed canary grass. The results of the analysis showed that Lucerne and Miscanthus, during the first–sixth years period, have lower indirect energy input (from 15.2 to 3.2 GJ/ha and 15.6 to 3.2 GJ/ha) than Switchgrass (from 20.9 to 3.2 GJ/ha) and Reed canary grass (from 16.7 to 3.2 GJ/ha). However, the highest direct energy input was determined by Lucerne (from 15.7 to 1.6 GJ/ha), and Miscanthus (from 11.9 to 0.9 GJ/ha) compared to Switchgrass (from 7.4 to 1.8 GJ/ha) and Reed canary grass (from 8.1 to 1.6 GJ/ha). Additionally, the lowest result of the direct economy and indirect economy costs was determined by Lucerne (from 3.9 to 3.7 kEUR/ha (direct) and 9.9 to 2.1 kEUR/ha (indirect)) and by Miscanthus (from 2.4 to 4.9 kEUR/ha (direct) and 11.8 to 1.9 kEUR/ha (indirect)) compared to Switchgrass (5.9 to 5.7 kEUR/ha (direct) and 17.5 to 2.1 kEUR/ha (indirect)), and reed canary grass (from 5.3 to 4.9 kEUR/ha (direct) and 13.7 to 1.9 kEUR/ha (indirect), respectively. The assessment of environmental performance revealed that Reed canary grass and Miscanthus had a more pronounced impact on Acidification. In contrast, Lucerne and Switchgrass had a more significant impact on Eutrophication indicators. The crop cultivation of four perennial crops impacted the environment in various significant ways. Despite the varying environmental impacts of the four perennial crops, the analysis revealed that all of them have the potential to increase biogas production.

Assessment of Earthworm Services on Litter Mineralisation and Nutrient Release in Annual and Perennial Energy Crops (Zea mays vs. Silphium perfoliatum)

Abundant and functionally diverse earthworm communities in perennials deliver ecosystem services like increasing nutrient availability by incorporating organic matter. This study aimed to analyse the decomposition of annual and perennial energy crop residues, and the subsequent nutrient release, depending on earthworm functional diversity. In a laboratory experiment, two ecological earthworm groups—anecics (detritivorous Lumbricus terrestris (L.)) and endogeics (geophagous Aporrectodea caliginosa and A. rosea)—were incubated with wilted cup plant (Silphium perfoliatum) and maize (Zea mays) litter for 4 or 8 weeks. Decomposition and consumption rates were calculated. The C, N and P in litter and casts were analysed. Mineralisation was a function of earthworm biomass and the number of individuals. Functional diversity had no beneficial effect. Decomposition was found to be highest in treatments with detritivorous earthworms, i.e., higher earthworm biomass, yet consumption and nutrient turnover in relation to earthworm biomass were higher in treatments with geophages indicating enhanced competition. N limitation became apparent in both litter treatments and was predominant with cup plant litter. N limitation and recalcitrant cell wall compounds affected consumption rates and the egestion of total C and P. While N in casts was lower than expected, P was increased. We observed that the effects manifested at different stages of decomposition of maize and cup plant, highlighting differences in temporal development of decomposition and nutrient turnover between litter types. Our results indicate that earthworms promote decomposition of recalcitrant litter and nutrient turnover, but N limitation may hamper nutrient release. Cup plant systems offer a suitable habitat for soil-dwelling organisms, but management approaches must consider the adequate input of organic matter as an energy and nutrient source to enhance ecosystem service provision.

ПРОЄКТИ, РЕАЛІЗОВАНІ В УкрНДІПВТ ім. Л. Погорілого

Summary The purpose of this work is to highlight the range of scientific and industrial projects implemented in L. Pogorilyy UkrNDIPVT during the last years, and promising directions of the institution’s activities. Methods and materials: a comprehensive analysis of the available results of project solutions implemented in UkrNDIPVT and scientific publications in the direction of this research. Results. In recent years, in the experimental fields of UkrNDIPVT named after L. Pogorily implemented a number of projects related to the implementation of promising technical and technological solutions for the implementation of various tillage systems and their impact on the efficiency of growing the main agricultural crops, the implementation of new methods of forecasting the yield of agricultural crops, optimization of technologies for growing perennial energy crops, etc. In particular, the following projects were implemented: “AgroOlymp” - the latest technical and technological solutions for a differentiated system of soil cultivation and sowing when growing grain crops; “Agroperspective” is a complex multivariate test of the productivity of new varieties and hybrids of agricultural crops typical for the Forest-Steppe of Ukraine in real production conditions of a demonstration crop rotation; “MARS” – monitoring of agro-resource systems and forecasting of the productivity of the main agricultural crops using the data of remote sensing of the Earth; “Biotechnology” - greening of technologies, extended reproduction of soil fertility, increase in the economic efficiency of growing agricultural crops; “Strip-till” - development of technical and technological solutions for strip tillage and sowing for small and medium-sized farms; “Bioenergy Conveyor” - development and optimization of technologies for growing perennial energy crops, which ensure obtaining the maximum amount of raw materials for the production of thermal energy from a unit of area. In addition to active scientific work, UkrNDIPVT named after L. Pohoriloy also works in the field of testing and ranking of technical means for the agro-industrial complex of Ukraine and helps manufacturers of agricultural machinery overcome the path of promotion to European markets Conclusions. Analysis of the implemented in UkrNDIPVT named after L. Pogorily of project solutions certifies that the institution’s active research and testing activities have quite fruitful results and broad prospects for the implementation of scientific and industrial ideas in the agricultural direction.

Ecosystem services and economic competitiveness of perennial energy crops in the modelling of biomass potential – A case study of the Czech Republic

The paper focuses on the design of a methodology that links the modelling of biomass potential from agricultural land using geographic information systems (derivation of biomass yields according to soil, topographical and climatic characteristics) with the growing need to provide non-productive functions contributing to sustainable land use and ensure the economic viability of biomass from energy crops. According to the proposed methodology, perennial energy crops are prioritized for allocation where the land risk index is highest. The land risk index is determined by assessing 5 basic characteristics - landscape connectivity, landscape heterogeneity, threat of drought, threat of water erosion and threat of soil erosion. In order to assess the economic competitiveness of biomass produced, a methodology for determining biomass production price is used, with the aim of matching the economic effect of growing conventional crops. Land best allocated to perennial energy crops is characterized by a high land risk index value and a competitive biomass production price. The application of the methodology is demonstrated using the case study of the Czech Republic. The results of the case study show that when energy crops are selected based on a combination of necessary non-productive functions and economic competitiveness, this significantly influences the allocation of perennial energy crops to individual land blocks and their contribution to biomass energy potential.

Determining spatially varying profit‐maximizing management practices for miscanthus and switchgrass production in the rainfed United States

AbstractDetermining optimal management practices for the profitable production of perennial energy crops is critical for scaling up production beyond experimental levels. Although many experimental field studies have examined the effects of management practices on the performance of miscanthus and switchgrass, there are no recommendations for economically optimal nitrogen (N) application rates and how they should vary spatially and with the age of the energy crop as well as on optimal rotation age of the energy crop to maximize profits. We develop a modeling framework to determine economically optimal crop management decisions and simulate the variability under various scenarios for miscanthus and switchgrass production across 2287 counties in the rainfed United States. We find that profit‐maximizing N recommendations for these crops vary across maturity stages and regions and can increase the landowner's profits compared with a uniform N rate across ages and regions. We also find that the optimal rotation for these crops is shorter than the productive physical lifespan (15–20 and 10 years for miscanthus and switchgrass, respectively). Specifically, the N rate that maximizes the economic returns is negligible for miscanthus and 111 kg ha−1 for switchgrass production at age 2. The mean profit‐maximizing N rate increases with age for miscanthus, peaking at 151 kg ha−1 at age 11 before declining to 114 kg ha−1 at the optimal rotation age of 13 years while that for switchgrass is 150 kg ha−1 for middle‐aged stands and declines to 114 kg ha−1 at the optimal rotation of 8–9 years. We find that miscanthus is the most profitable energy crop in the northern region of the rainfed United States while switchgrass is most profitable in the south of the rainfed United States. Our findings are useful for improving assessments of the profitability of energy crops and guiding future management decisions by landowners.

Profit‐maximizing of perennial energy crop production through optimized management practices: A commentary on Zhang et al. (2022)

I was invited to make a brief commentary on a recent article titled “Determining Spatially Varying Profit‐Maximizing Management Practices for Miscanthus and Switchgrass Production in the Rainfed United States” published in GCBB by Zhang et al. (2022). In the work, they propose management practices to maximize profitability through economically optimal N fertilizer application, temporal and spatial variation, and optimal age rotation of two energy crops. This interesting and thoroughly investigated result would be instructive for the applications of perennial energy crops.