Annual Biomass Production Research Articles

The effect of oil shale ash and mixtures of wood ash and oil shale ash on the above- and belowground biomass formation of Silver birch and Scots pine seedlings on a cutaway peatland

Use of biofuel ashes for the afforestation of cutaway peatlands helps to balance the content of nutrients in peat substrate, which improves the survival of planted seedlings and increases significantly bio-production. The purpose of this study was to investigate the effect of fertilization with alkaline ashes on the above- and belowground biomass formation of four-year-old Silver birch (Betula pendula Roth) and five-year-old Scots pine (Pinus sylvestris L.) stands on a cutaway peatland. Five treatments were established: three mixtures with different proportions of wood ash (10–15tha−1) and oil shale ash (10–15tha−1), pure oil shale ash (10tha−1) and control (unfertilized plot). Three years after fertilization with ashes the content of phosphorus was up to 150 times and that of potassium 23 times higher in the peat substrate treated with ashes than on the control plot. The growth and biomass formation varied among treatments and depends strongly on the content of P and K in the growth substrate. The best results were observed on plots of Silver birch treated with mixed ashes; there the seedlings annual height increment was 2–3 times (first year), 5–7 times (second year) and 8–9 times (third year) greater than on the control plot. The effect of mixed ashes on the annual height increment of Scots pine was weaker: the annual height increment was 1.4 times (first year), 3 times (second year) and 5 times (third year) greater than on the control plot. The effect of pure oil shale ash on the growth and biomass formation of trees was the smallest. The greatest root collar diameter increment of birch and pine was observed on the third vegetation period. Roots formed the largest part of the total Silver birch biomass, followed by stem, branches and leaves. At the end of the third year after treatment the largest part of the biomass of Scots pine was allocated to the needles, followed by roots, stem and branches. The biomass and biomass production were the greatest on the plots treated with mixed ashes, especially on the WA15+OSA10 and WA15+OSA10 treatments. The total bio-productivity of birch was until 4 times intense than in the case of pine. The average current annual biomass production of Silver birch and Scots pine stands were respectively 0.17–0.21t ha−1 and 0.3–0.56t ha−1 (mixed ashes), 0.04t ha−1 and 0.16t ha−1 (OSA10) and 0.02t ha−1 (control).

Abiotic and Biotic Formation of Amino Acids in the Enceladus Ocean

The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H2 production of 0.6-34 mol/s from serpentinization, sufficient to sustain abiotic and biotic amino acid synthesis of 1.6-87 and 1-44 g/s, respectively. Two-dimensional (2D) numerical simulations of the hydrothermal vent suggest that the vent fluids could reach the ice-water boundary in less than 11-55 days for a 50 km deep ocean diluted by ambient ocean water 10 to 1. Concentrations of glycine, alanine, α-amino isobutyric acid, and glutamic acid in the plume and in the ambient ocean could all be above 0.01 μM just due to abiotic production. Biological synthesis, if occurring, could produce a maximum of 90 μM concentrations of amino acids based on a methanogenic ecosystem consuming H2 and CO2. Racemization timescales in the ocean are short compared with production timescales. Thus, no enantiomeric excess is expected in the ambient ocean, and if biology is present, enantiomeric excess at the vent fluids is expected to be less than 10% in the plume. From vent H2 concentrations of 7.8 mM (e.g., Lost City) and assuming complete H2 use and conversion to chemical energy by methanogens, cell production is estimated. Annual biomass production in the methanogenic-based biology model is 4 × 104-2 × 106 kg/year. This corresponds to cell concentrations ∼109 cells/cm3 in the vents and ∼108 cells/cm3 in the plume, and when diluted into the ambient ocean, we predict cell concentrations of 80-4250 cells/cm3. Key Words: Abiotic organic synthesis-Enceladus-Extraterrestrial life. Astrobiology 17, 862-875.

An Integrated Landscape Management Approach to Sustainable Bioenergy Production

Integrated landscape management has emerged in recent years as a methodology to integrate the environmental impacts of various agricultural practices along with yield and profitability in a variety of cropping systems. In this study, the Landscape Environmental Assessment Framework (LEAF), a decision support toolset for use in integrated landscape management and developed at Idaho National Laboratory, was used to evaluate the profitability of grain-producing subfields, to determine the efficacy of sustainably harvesting residual biomass after grain harvest, and to determine the efficacy of integrating bioenergy crops into grain-producing landscapes to enhance farmer profitability. Three bioenergy crops, sorghum, switchgrass, and miscanthus, were integrated into non-profitable subfields in four US counties. The manuscript describes in detail the material and methods used to define crop rotations, land management units and practices, subfield units and productivity, grain profitability, sustainability criteria, energy crop integration, and feedstock cost estimation. With the integration of bioenergy crops, the overall annual biomass production rates in the four counties could be increased by factors ranging from 0.8 to 21, depending on the energy crop and county, over the annual residue biomass production rates. By modeling the harvesting of residual biomass and energy crops using geo-referenced, precision harvesting equipment and optimal harvesting paths on individual subfields, the average logistics costs including harvesting of both residual biomass and energy crops were observed to fall well below US DOE’s 2017 goals for biomass feedstock price of US$84/ton or US$92.6/dry Mg. Miscanthus, grown in counties in Ohio and Kansas, provided the maximum potential, among the three energy crops considered, for increment in biomass production and also posed maximum threat to the grain production. Considerable variability was observed in the harvesting and total costs because of the size, shape, and productivity of individual subfields. It was shown that variability in the harvesting costs could be used to down-select non-profitable farms with low harvesting costs and high residue and bioenergy crop yields and to reduce the negative impacts of bioenergy crop integration into croplands on grain production. The results of the assessment suggest that (1) the potential to produce biomass is considerably enhanced when non-profitable grain-producing subfields are replaced by bioenergy crops and (2) the subfield-scale integrated landscape assessment provides a defensible methodology to directly address individual farmer’s profitability, sustainability, and environmental stewardship.

Carbon saturation and assessment of soil organic carbon fractions in Mediterranean rainfed olive orchards under plant cover management

Abstract Olive groves are undergoing a marked change in the way that inter-row land is managed. The current regulation and recommendation encourages the implementation of plant cover, mainly to improve soil fertility and reduce erosion. However, there is no quantitative information on the dynamics and pools of soil organic carbon (SOC) fractions of different protection levels of the plant-residue-derived organic carbon (OC). This study was conducted to provide a range of annual OC inputs in commercial olive oil groves under natural plant cover, to assess the influence of the annual application of aboveground plant cover residues on unprotected and physically, chemically and biochemically protected SOC. In addition, we tested the carbon saturation hypothesis under plant cover. Ten olive oil orchards under plant cover management (PC), together with five comparable bare soil olive oil orchards (NPC) were selected and annual aboveground natural plant residues and SOC pools were sampled and quantified. Annual aboveground plant cover biomass and OC production in PC olive orchards averaged 1.48 t dry-weight (DW) ha −1 and 0.56 t C DW ha −1 , respectively with a great variability among sites (coefficient of variation of about 100%). SOC concentration in PC orchards was, on average, 2.8 (0–5 cm soil) and 2.0 (5–15 cm) times higher than in bare soils of NPC, and the pool of protected SOC in the top 15 cm was 2.1 times higher in the PC (17.9 mg C g −1 ± 5.7) (±standard deviation) compared to NPC (8.5 mg C g −1 ± 2.9) olive orchards. Linear or saturation type relationships between each SOC fraction and total SOC content for the range of SOC of the commercial olive oil orchards were statistically indistinguishable, and thus linear models to predict SOC accumulation due to plant cover in olive orchards are suitable, at least for the studied range of SOC. Overall, at regional scale where olive oil groves represent a very high proportion of the agricultural land, the use of plant cover appears to be a promising practice that promotes protection of the SOC, thus improving SOC sequestration.

Carbon budgets in fertile grey alder (Alnus incana (L.) Moench.) stands of different ages

Estimation of the carbon (C) storages and fluxes in different forest ecosystems is essential for understanding their C sequestration ability. Grey alder (Alnus incana (L.) Moench) is a fast growing tree species with a great potential for short-rotation forestry in the Nordic and Baltic countries and its stands are considered C accumulating ecosystems. We hypothesized that grey alder stands growing at fertile sites act as C sinks in the young and middle-age stages, while mature stands become C sources as a consequence of declined net primary production (NPP). Net ecosystem production (NEP) was studied in five grey alder stands aged between 9 and 40years. It was found that the NEP of the studied grey alder stands of different ages varied from −1.98 to +4.14tCha−1yr−1. The oldest grey alder stand proved to be a weak C source (−0.77tCha−1yr−1). However, also young alder stands regenerated in a clear-cut area may emit C in the earlier stage, owing to previous cutting and decomposition of organic residues matter. In this aspect, the land use history is of great significance.Leaf litter accounted for the largest (44–61%) annual organic C input to soil, the fine roots contributed with 12–32% and the herbaceous understorey (aboveground+belowground), with 14–26% to it. Annual cumulative soil heterotrophic respiration (Rh) in the studied stands ranged between 2.6 and 5.8tCha−1yr−1; C leaching was negligible, being 10–30kgCha−1yr−1. The C sequestration to soil depended on previous land use; in the first forest generation, i.e. a stand growing on previous agricultural land, the annual Corg input into soil exceeded Rh, which indicated C accumulation in soil. Although grey alder stands are generally C accumulating ecosystems, the annual biomass production of the studied stands was highly variable; thus annual NEP depended on the effect of the year rather than on stand age. The current study demonstrates that use of repeated time-series measurements applied for stands of different development stages can provide more detailed estimation of C accumulation in forest ecosystems.

How methodological choices affect LCA climate impact results: the case of structural timber

Life cycle assessment (LCA) is broadly applied to assess the environmental impact of products through their life cycle. LCA of bio-based products is particularly challenging due to the uncertainties in modeling the natural biomass production process. While uncertainties related to inventory data are often addressed in LCA by performing sensitivity analyses, the sensitivity of results to LCA methodologies chosen is seldom addressed. This work investigates the influence of common methodological choices on LCA climate impact results of forestry products. Performing a consequential LCA, the study compares results obtained through different choices concerning four methodological aspects: the modeling of land use change effects, the choice of climate metric for impact assessment, the choice of time horizon applied, and the completeness of the forest carbon stock modeled. Eight scenarios were tested, applied to the same case study to ensure the full comparability of the results. A dynamic life cycle inventory of annual forest biomass production and degradation was obtained through a methodology accounting dynamically for the annual carbon fluxes in a forest plot. The results obtained for the eight scenarios showed a great variability of the estimated climate effect, ranging from a net carbon sequestration of 24 kg CO2 equivalents to a net carbon emission of 3220 kg CO2 equivalents, though seven out of eight scenarios resulted in a net carbon emission. The results are particularly sensitive to the choice of time horizon, especially when combined with the choice of static or dynamic climate indicator and different climate metrics as GWP and GTP. The case study showed a lower variability of results to the choice of forest carbon stock compared to the effect of the other tested assumptions. LCA results of forestry products were highly sensitive to the tested methodological choices. A description and motivation of these choices is required for a clear and critical interpretation of the results. The choice of climate indicator and TH applied depends on the goal and scope of the study and strongly affects the contribution to climate impact results of all LCA processes. Those choices need to be carefully discussed and should be in accordance with the goal of the study, since different climate metric and TH have distinct interpretations. The interpretation of different climate indicators and their time horizons should be linked with the considered endpoints of climate change.

The Eurotiomycete Apinisia graminicola as the causal agent of a leaf spot disease on the energy crop Miscanthus x giganteus in Northern Germany

Miscanthus x giganteus is a fast growing, perennial energy crop for temperate climates. Because of its high annual biomass production rates and its characteristics as a low-input crop, an expansion of field cultivation can be anticipated to cover increasing demands for sustainable biomass production. However, knowledge about pathogens that could have an impact on biomass production is still limited for M. giganteus. Here, we report about the isolation of the filamentous fungus Apinisia graminicola from necrotic leaf lesions of M. giganteus grown on a field trial plot in Northern Germany. Inoculation assays with the isolated A. graminicola strain confirmed its capacity to cause a leaf spot disease on M. giganteus. Additional inoculation assays revealed that A. graminicola also caused necrotic lesions on leaves of the model grass Brachypodium distachyon. Generally, symptoms of A. graminicola-caused leaf spot disease were stronger on B. distachyon compared to M. giganteus. Incubation temperatures above 22 °C during A. graminicola infection resulted in stronger disease symptoms on both, M. giganteus and B. distachyon leaves. Microscopic analysis of cross sectioned, infected leaf tissue revealed an epiphytic mycelium formation on the surface and an endophytic colonization of the mesophyll leave tissue, especially in M. giganteus. Our results revealed that the isolated A. graminicola strain is a causal agent of a leaf spot disease on grass leaves. Its potential on endophytic growth in M. giganteus might open new possibilities in studying this type of plant-fungal interaction on a cellular and molecular level in an energy crop.

Relationship between soil nutritive resources and the growth and mineral nutrition of a beech (Fagus sylvatica) stand along a soil sequence

In forest ecosystems, the specific influence of soil resources on stand productivity is difficult to assess because many other ecological variables also affect tree growth. In this study, we took advantage of a natural soil gradient, from shallow calcic soil to deep acidic soil, all with similar climate, atmospheric depositions, species composition and management, to determine the relationship between soil nutritive resources and the growth and mineral nutrition of a beech (Fagus sylvatica) mature forest of Northeastern France. Soil resources were assessed through the quantification of the stocks of available water and mineral nutrients (Ca, Mg, K and P2O5). Beech stand growth and mineral nutrition were determined through the use of several indicators, i.e., standing aboveground biomass and annual biomass production, potential growth index (prediction of the height of dominant trees at 100years) and foliar nutrient content. We observed a gradient of nutritive resources in soils as well as a gradient of stand growth on the study site: the current aboveground biomass was highest on the calci-brunisol which presented the highest water and nutrient stocks while it was lowest on the rendisol, characterized by a very low water holding capacity and a very low stock of available K. However, the growth of beech trees on the rendisol was equivalent to the highest growth classes of beech trees in France, and K nutrition was optimal. Observations on the study site suggest that, in favorable climate conditions, some biological adaptation processes, such as an efficient root colonization as well as an efficient nutrient cycling may allow to maintain stand growth and nutrition on soils with low water and nutrient reserves. The fertility of forest soils has thus to be assessed in a dynamic way by integrating nutrient fluxes as well as the adaptations of trees to environmental constraints. The biological processes become an increasingly important part in the conservation of soil fertility, notably in the perspective of global changes.

Species composition but not diversity explains recovery from the 2011 drought in Texas grasslands

AbstractExtreme droughts can have profound direct consequences for grassland ecosystems, but it is poorly known how ecosystems recover from drought and what ecological factors are associated with recovery. Recovery occurs when ecosystem functioning returns to values observed prior to a perturbation. Here, we tested for ecosystem recovery after an extreme drought in 2011 in previously established native and exotic experimental communities in Central Texas. Planted mixtures of all native and all exotic species were crossed with a summer irrigation treatment, with eight community compositions (random draws) per treatment. Prior to the drought, native plots had higher diversity than exotic plots, which sets up the prediction that the high‐diversity native plots will recover more quickly than exotics. The extreme drought decreased rain‐use efficiency ([RUE], annual biomass production per unit of rainfall) by 82%. Rain‐use efficiency remained well below pre‐drought levels during the growing season after the drought. However, on average, RUE recovered to pre‐drought levels by the second growing season following drought. Exotic communities showed higher RUE than native communities, and irrigation significantly reduced RUE in both exotic and native communities across years. Interestingly, not all of the mixtures recovered from the drought, and recovery was associated with species composition, but not diversity. Rain‐use efficiency recovery from drought was greatest in native communities in which the proportion of C3 forb biomass increased during and following drought and in exotic communities with a low proportion of short grass biomass. Extreme droughts can exert differential impacts on plant functional groups, leading to a drought legacy effect that reduces recovery with possible long‐term repercussions.

An initial investigation of forage production and feed quality of perennial wheat derivatives

Perennial cereals may offer a novel forage source in mixed farming enterprises while improving the sustainability of grain farming. There has been limited analysis of the quality of this forage type and its likely value to mixed grazing/cropping farming systems. This study evaluated the biomass and grain production of four wheat × wheatgrass hybrid experimental lines under four simulated grazing regimes; nil defoliation (grain only; D0), defoliate once (D1), defoliate twice (D2) and defoliate twice followed by a simulated hay cut (D3), and compared performance to a winter wheat, Wedgetail, and the perennial grass Thinopyrum intermedium. Early biomass production of the perennial entries was significantly less than Wedgetail (P = 0.01). Grain yield from Wedgetail was generally higher (P < 0.001) than all other lines. As defoliation frequency increased, the comparative difference in grain yield between Wedgetail and the hybrid entries decreased, with lines OK7211542 and 11955 exceeding the grain yield of Wedgetail in the D3 treatment. Cumulative annual biomass production of the hybrid lines exceeded that of Wedgetail, though the seasonal production differed markedly. Generally there was limited decline in perennial plant population between April and December in both years of the experiment. Defoliation had little impact on perennial plant survival; however, none of the hybrids could sustain a significant plant population beyond the second summer of the experiment. Yield declines of the hybrid entries was due to increasing plant mortality, rather than a predisposed yield limitation of the germplasm, as all hybrid entries either maintained or increased their grain yield on a per plant basis. In contrast, the perennial grass maintained a constant population for the duration of the experiment. Dry matter digestibility and energy content of all forages tested were high, averaging 80.2% and 13.3 MJ ME/kg DM, respectively. Crude protein was higher (P < 0.001) in Th. intermedium and the hybrid entries with 62% and 25% more crude protein than Wedgetail, respectively. All cereals had very high potassium : sodium and low calcium : phosphorus ratios, which indicated the need to provide mineral supplements to grazing animals to maintain growth rates and manage animal health disorders, similar to conventional grazing cereals. This paper discusses the role perennial cereals could play in a sustainable expansion of the cropping zone in south-eastern Australia.

Dynamic of nematode communities in energy plant cropping systems

The perennial cropping system of the cup plant (Silphium perfoliatum) might counteract major drawbacks of intensively managed annual biomass production systems due to a long-term reduction of agricultural management. In this context, the ecological value of the cup plant was assessed for free-living soil nematodes to reveal changes in soil biodiversity and functions associated with cultivation period length. For this purpose, cup plant fields from a chronosequence were sampled in two consecutive years and compared to energy maize production systems. Nematodes were identified on a family level and assigned to feeding guilds. General and nematode-specific diversity indices, as well as multivariate redundancy analysis were used to assess changes in community structure. General mixed-effects modeling and multi model averaging were applied to reveal the influence of cultivation period length and environmental factors on nematode assemblages. Major changes were found in almost all trophic groups. In the long-term, abundances of herbivores, fungivores and carnivores increased along with total nematode abundance. Bacterivores remained almost unchanged, but decreased in dominance. Old cup plant fields (8+ years) showed mass occurrences of Helicotylenchus spp.. In cup plant fields, facilitation of fungal decomposer channels and top-down regulation within the nematode food web could improve soil fertility and soil quality. However, long-term dynamic of the nematode community was not indicative of succession and remained characteristic for agroecosystems, hence positive effects are presumably restricted to conversion of farmed land.

Potential of biogas production to reduce firewood consumption in remote high-elevation Himalayan communities in Nepal

Remote communities in the Nepalese mountains above 2500 m a.s.l. belong to the most precarious in the world. Inhabitants struggle for the minimum in terms of safe drinking water, food and sanitation. Reliable, affordable and clean energy for cooking, room heating and warm water for personal hygiene is often lacking and dependency on firewood very high. The remoteness and unlikeliness of electric grid connection in the coming decades make a diversified energy supply from renewable local resources crucial. Small-scale anaerobic digestion (AD) of organic substrates has been used for long in rural areas of developing countries to produce biogas as energy source and recover residue as organic fertilizer. AD is challenging at high elevations due to year around lower ambient temperatures and lower annual biomass production per area compared to lowlands. Nevertheless, examples of operational household AD exist even above 3000 m a.s.l. in the Andes. Here we compare firewood consumption with biogas potential from organic substrates in a community with 39 households at 3150 m a.s.l. in Jumla District, Nepal. In five households with varying numbers of members and animals kept, mean firewood use and its energy content per capita (cap) and day (d) were 2.1 kg or ca. 25 MJ in spring and 2.3 kg or ca. 28 MJ in winter. Easily available substrates include cow, sheep and horse dung from overnight shelters and human excrements from pit latrines, amounting on average to 1.7 kg wet weight (kgww ) cap−1 d−1 in spring and 2.2 kgww cap−1 d−1 in winter. Adjusted to normal conditions (Nm3 at 0 °C, 1013.15 hPa), these substrates yielded on average 0.08 Nm3 cap−1 d−1 biogas in spring and 0.12 Nm3 cap−1 d−1 in winter (35–60% methane content) in biochemical methane potential (BMPs) tests at 36 °C. This could provide up to 60% of basic cooking needs on average and up to 75% in a “typical” household in terms of members and animals kept. Of the overall thermal energy needs including also room heating ca. 10–20% could be covered, substituting 0.1–0.4 (mean: 0.2) kg firewood cap−1 d−1 . If only animal dung and human excrements are considered, no competition for resources arises as residues can still be used as organic fertilizer. This study supports the design and introduction of planned pilot digesters integrated into on-going community development including pit latrines for substrate availability, greenhouses as possible way of thermal insulation, and planned pico-hydropower plants to use excess electricity during the night for digester heating.

LEMONGRASS OIL - A MAJOR SOURCE OF INCOME FOR THE TRIBALS OF WAYANAD DISTRICT KERALA

Paniyas, Adiyas, Kattunaikan, Kuruman, Karimbalan and Kurchiyas are the native tribal communities and inhibiting the Wayanad district of Kerala. Most of the tribals have engaged in the collecting of minor forest produce and lemongrass cultivation. They have also involved as agriculture labours and casual laboursfor forest dept etc to meet their demand for basic livelihood. Cultivation of lemongrass for oil distillation is considered to be one of the major sources of income for them. The oil yield was determined on basis of grass biomass distilled and the quantity of oil extracted. Among the study areas, Pulpally registered higher annual biomass production of lemongrass (8380 kg/acre) followed by Ambalavayal (7800 kg/acre), Meppadi (7540 kg/acre) and Mananathavady (6440 kg/acre). Lemongrass cultivation and extraction of lemongrass oil from the host provide better job oppurtunities and fairly good economic return in Wayanad district.

Managing peatland vegetation for drinking water treatment.

Peatland ecosystem services include drinking water provision, flood mitigation, habitat provision and carbon sequestration. Dissolved organic carbon (DOC) removal is a key treatment process for the supply of potable water downstream from peat-dominated catchments. A transition from peat-forming Sphagnum moss to vascular plants has been observed in peatlands degraded by (a) land management, (b) atmospheric deposition and (c) climate change. Here within we show that the presence of vascular plants with higher annual above-ground biomass production leads to a seasonal addition of labile plant material into the peatland ecosystem as litter recalcitrance is lower. The net effect will be a smaller litter carbon pool due to higher rates of decomposition, and a greater seasonal pattern of DOC flux. Conventional water treatment involving coagulation-flocculation-sedimentation may be impeded by vascular plant-derived DOC. It has been shown that vascular plant-derived DOC is more difficult to remove via these methods than DOC derived from Sphagnum, whilst also being less susceptible to microbial mineralisation before reaching the treatment works. These results provide evidence that practices aimed at re-establishing Sphagnum moss on degraded peatlands could reduce costs and improve efficacy at water treatment works, offering an alternative to ‘end-of-pipe’ solutions through management of ecosystem service provision.

Developing manufactured soils from industrial by‐products for use as growth substrates in mine reclamation

AbstractSuitable soils for reclamation can be acquired through excavation and translocation of local soils, increasing the industrial footprint on previously undisturbed lands and causing negative environmental impacts. Manufactured soils (Technosols) could be a viable soil source when the availability of suitable natural soils is limited. The purpose of this study was to manufacture a Technosol from an admixture of woody residuals, primary paper sludge, and two subtypes of nonacid generating crushed mine rock, to function as a growth substrate for revegetation of mined land. Technosols manufactured with 0, 25, 50, and 75% organic materials (v/v) were assessed in a 10‐week growth study using annual ryegrass biomass production and allocation as a performance indicator. Technosols containing no organic materials had significantly lower plant nutrient concentrations than Technosols containing an organic constituent and, after 5 weeks of growth, ryegrass grown on nonorganic Technosols had greater root:shoot ratios than ryegrass grown on organic Technosols. Organics increase the water holding capacity and nutrient concentrations of Technosols and should be included in manufacturing Technosols for revegetation. Technosols manufactured with primary paper sludge produced lower shoot biomass than Technosols manufactured with woody residuals, which could be in part due to the higher pH of the paper sludge. Technosols can be manufactured for revegetation purposes and individual components should be assessed before and after mixing. Further development of Technosols should include field testing and amendment or fertilizer use to improve soil nutrient content.

Annual brown shrimp (Crangon crangon) biomass production in Northwestern Europe contrasted to annual landings

The brown shrimp (Crangon crangon) fishery is economically one of the most important fisheries in the North Sea. Fishing is unregulated, apart from the number of licenses and technical measures. The fishery has long been considered sustainable in terms of the effect on the target species, even though annual stocks are not regularly assessed. Average landings constantly increased annually and since 2000 have been 40% higher than in the 1980s and 1990s. Because brown shrimp lack a clear age structure and reproduce almost year-round, an agebased stock assessment is not possible. In the absence of a formal estimate of stock size, it is difficult to judge whether current fishing practices can still be considered sustainable. Here, we use annual survey data collected during peak occurrence in late summer to obtain a depth- and area-stratified, swept-area estimate for the period 1970–2015. The resulting estimate of the total commercial-size shrimp biomass varied between 4000 and 21 000 tonnes over the years. Both parametric and non-parametric methods arrived at very similar results. In combination with length-based mortality estimates (as a proxy for production/biomass ratio), knowledge on the seasonal occurrence, catchability, gear efficiency, and their variation, total adult annual biomass production was estimated. Values ranged between 38 000 and 216 000 tonnes and overlapped at the lower end with total annual commercial landings, which varied between 8000 and 38 500 tonnes, indicating that in some years (1977, 1998, 2007), the larger part of the total brown shrimp production was harvested. Annual brown shrimp landings have gradually increased since the series started, whereas no trend in standing biomass and production was detected. Concurrent with the increase in landings, natural mortality of shrimp by predation has diminished. Considering the increase in fishing pressure and unknown consequence if natural predators recover or shrimp recruitment decreases, the lack of management for the brown shrimp fishery needs to be reconsidered.

A flexible parametric model for a balanced account of forest carbon fluxes in LCA

Despite a mature debate on the importance of a time-dependent account of carbon fluxes in life cycle assessments (LCA) of forestry products, static accounts of fluxes are still common. Time-explicit inventory of carbon fluxes is not available to LCA practitioners, since the most commonly used life cycle inventory (LCI) databases use a static approach. Existing forest models are typically applied to specific study fields for which the detailed input parameters required are available. This paper presents a simplified parametric model to obtain a time-explicit balanced account of the carbon fluxes in a forest for use in LCA. The model was applied to the case of spruce as an example. The model calculated endogenous and exogenous carbon fluxes in tons of carbon per hectare. It was designed to allow users to choose (a) the carbon pools to be included in the analysis (aboveground and belowground carbon pools, only aboveground carbon or only carbon in stem); (b) a linear or sigmoidal dynamic function describing biomass growth; (c) a sigmoidal, negative exponential or linear dynamic function describing independently the decomposition of aboveground and belowground biomass; and (d) the forest management features such as stand type, rotation time, thinning frequency and intensity. The parametric model provides a time-dependent LCI of forest carbon fluxes per unit of product, taking into account the typically limited data available to LCA practitioners, while providing consistent and robust outcomes. The results obtained for the case study were validated with the more complex CO2FIX. The model ensures carbon balance within spatial and time delimitation defined by the user by accounting for the annual biomass degradation and production in each carbon pool. The inventory can be used in LCA studies and coupled with classic indicators (e.g. global warming potential) to accurately determine the climate impacts over time. The model is applicable globally and to any forest management practice. This paper proposes a simplified and flexible forest model, which facilitates the implementation in LCA of time-dependent assessments of bio-based products.

Potential for Production of Perennial Biofuel Feedstocks in Conservation Buffers on the Coastal Plain of Georgia, USA

With global increases in the production of cellulosic biomass for fuel, or “biofuel,” concerns over potential negative effects of using land for biofuel production have promoted attention to concepts of agricultural landscape design that sustainably balance tradeoffs between food, fuel, fiber, and conservation. The Energy Independence Security Act (EISA) of 2007 mandates an increase in advanced biofuels to 21 billion gallons in 2022. The southeastern region of the USA has been identified as a contributor to meeting half of this goal. We used a GIS-based approach to estimate the production and N-removal potential of three perennial biofeedstocks planted as conservation buffers (field borders associated with riparian buffers, and grassed waterways) on the Coastal Plain of Georgia, USA. Land cover, hydrology, elevation, and soils data were used to identify locations within agricultural landscapes that are most susceptible to runoff, erosion, and nutrient loss. We estimated potential annual biomass production from these areas to be: 2.5–3.5 Tg for giant miscanthus (Miscanthus × giganteus), 2–8.6 Tg for “Merkeron” napier grass (Pennisetum purpureum), and 1.9–7.5 Tg for “Alamo” switchgrass (Panicum virgatum). When production strategies were taken into consideration, we estimated total biomass yield of perennial grasses for the Georgia Coastal Plain at 2.2–9.4 Tg year−1. Using published rates of N removal and ethanol conversion, we calculated the amount of potential N removal by these systems as 8100–51,000 Mg year−1 and ethanol fuel production as 778–3296 Ml year−1 (206 to 871 million gal. US).

Genetic evaluation and selection index in tetraploidBrachiaria ruziziensis

AbstractHalf‐sib progenies of congo signal grass (Brachiaria ruziziensisGermain & Evrard, syn.:B. eminii,Urochloa ruziziensis) were analysed using a mixed model methodology. The objective was to estimate genetic and phenotypic parameters, predict individual genetic values, estimate correlations between characters associated with biomass production and forage nutritive value and use this information to determine the economic weights to compare three multiplicative selection indices. Individual narrow‐sense heritabilities corrected for inbreeding varied from 0.14 to 0.91 for characters associated with biomass production and from 0.04 a 0.24 for nutritional value characters. The correlations among characters associated with annual biomass production were of high magnitude. In contrast, biomass production characters were negatively correlated with crude protein, acid detergent fibre and lignin. Total dry matter yield, crude protein and regrowth ability were weighted separately in evaluations during wet and dry season or annually in selection indices. Index that considered characters annually resulted in better distribution of forage production along the year than indices that separated wet and dry season production.

Variation of biomass energy yield in wastewater treatment high rate algal ponds

Wastewater treatment high rate algal ponds (WWT HRAPs) have been recently highlighted as a potential system for low-cost algal energy production since the algal biomass is essentially a free by-product of the wastewater treatment process. This paper investigates the biomass energy yield potential of WWT HRAP (calculated by multiplying biomass productivity and biomass energy content). We address experimentally, for the first time, the influence of algal species dynamics, zooplankton grazing, environmental conditions, biomass chemical composition and biomass algal proportion on overall biomass energy yield. Two parallel identical pilot-scale HRAPs (8m3 volume, 0.3m depth and 31.8m2 surface area) were operated for one year and monitored each week for biomass productivity and energy content. Pond effluent nutrient concentration, microalgal relative abundance, biomass chemical composition and chlorophyll-a content were all measured and their effect on biomass productivity and energy content was assessed. The algal species composition and algal proportion in the HRAP effluent varied with season and grazing pressure. The highest biomass lipid content (45wt%) was achieved when effluent ammonia concentration was lowest (<1mg·L−1). Biomass productivity depended on season and zooplankton grazing pressure and biomass energy content increased algal proportion and lipid content of the HRAP biomass. The average biomass energy yield in the HRAPs was 113.3kJ·m−2·day−1 (based on the average annual biomass energy content of 19.2kJ·g−1 and the mean annual HRAP biomass productivity of 5.9gVSS·m−2·day−1 during the year). Biomass energy yield increased significantly during summer (175±5kJ·m−2·day−1) compared to winter (68±18kJ·m−2·day−1) since summer environmental conditions were more favorable for biomass growth. Results suggest improving algal proportion and productivity would promote biomass energy yield in WWT HRAP by enhancing biomass energy content and productivity concurrently.