Annual Biomass Production Research Articles

Development of integrated screening, cultivar optimization, and verification research (DISCOVR): A coordinated research-driven approach to improve microalgal productivity, composition, and culture stability for commercially viable biofuels production

To address major knowledge gaps and barriers to the commercial development of algal biomass for biofuels and co-products, a collaborative consortium, Development of Integrated Screening, Cultivar Optimization, and Verification Research (DISCOVR), was established in 2016. Funded by the U.S. Department of Energy (DOE) Bioenergy Technologies Office (BETO), this consortium constitutes a partnership between four DOE national laboratories - Pacific Northwest National Laboratory (PNNL), Los Alamos National Laboratory (LANL), the National Renewable Energy Laboratory (NREL), and Sandia National Laboratories (SNL) - and the Arizona Center for Algae Technology and Innovation (AzCATI) at Arizona State University.To address the barriers of strain selection for achieving high seasonal productivities with a suitable composition and culture resilience, a tiered strain down-selection pipeline is implemented. At Tier I, the temperature and salinity tolerance of strains is determined in flask cultures; at Tier II, the areal biomass productivity and composition is determined in climate-simulation photobioreactors; at Tier III, the productivity and culture stability are determined in outdoor raceways. The top performing strains move forward to long-term testing at the algae testbed site at AzCATI to generate annual biomass productivity data.Concurrent to the strain down-selection in the DISCOVR pipeline, hypotheses for increasing biomass productivity, shifting biomass composition to enhance intrinsic value, and improving culture stability and resistance to pests are also tested. Techno-economic analyses are carried out to determine whether promising findings from laboratory studies or proposed modifications in outdoor pond cultivation conditions translate into reductions in the minimum biomass selling price (MBSP). In the three years following the launch of DISCOVR, annual biomass productivity has increased from 11.7 to 17.6 g m−2 day−1, resulting in an MBSP decrease from 824 to 611 $ ton−1.

Declines in freshwater mussel density, size and productivity in the River Thames over the past half century.

A pioneering, quantitative study published in Journal of Animal Ecology in 1966 on freshwater mussel populations in the River Thames, UK, continues to be cited extensively as evidence of the major contribution that mussels make to benthic biomass and ecosystem functioning in global river ecosystems. Ecological alteration, as well as declines in freshwater mussel populations elsewhere, suggest that changes to mussel populations in the River Thames are likely to have occurred over the half century since this study. We resurveyed the site reported in Negus (1966) and quantified the changes in mussel population density, species composition, growth patterns and productivity. We found large declines in population density for all unionid species. The duck mussel Anodonta anatina decreased to 1.1% of 1964 density. The painter's mussel Unio pictorum fell to 3.2% of 1964 density. The swollen river mussel Unio tumidus showed statistically nonsignificant declines. In contrast to 1964, in 2020 we found no living specimens of the depressed river mussel Pseudanodonta complanata (classified as Vulnerable by the IUCN Red List) but found new records of the invasive, nonnative zebra mussel Dreissena polymorpha and Asian clam Corbicula fluminea. Additionally, we found strong decreases in size-at-age for all species, which now grow to 65-90% of maximum lengths in 1964. As a result of reduced density and size, estimated annual biomass production fell to 7.5% of 1964 levels. Since mussels can be important to ecosystem functioning, providing key regulating and provisioning services, the declines we found imply substantial degradation of freshwater ecosystem services in the River Thames, one of the UK's largest rivers. Our study also highlights the importance to conservationists and ecologists of updating and validating assumptions and data about wild populations, which in the present era of anthropogenic ecosystem alteration are undergoing significant and rapid changes. Regular population surveys of key species are essential to maintain an accurate picture of ecosystem health and to guide management.

Resource Recovery of the Wastewater-Derived Nutrients into Algal Biomass Followed by Its Cascading Processing to Multiple Products in a Circular Bioeconomy Paradigm

The cultivation of Plectonema terebrans BERC10 in wastewater and integrating the wastewater-derived biomass followed by its processing for multiple products in a biorefinery could help in achieving environmental sustainability and cost effectiveness. This study evaluated the resource recovery potential of the cyanobacterium Plectonema terebrans BERC10 from urban wastewater followed by the cascading processing of the biomass into multiple bioproducts. The annual biomass productivity ranged from 0.035–0.064 gL−1d−1 and contained 40–46% lipids and 20–38% protein. The cascading processing of the biomass resulted in multiple products, including 53 mgg−1 of high-value pigments and high-quality biodiesel in accordance with American and European standards. The pigment-free and de-fatted residual biomass was used as a sole feedstock (30–70 gL−1) to produce enzymes and mycoproteins via fungal fermentation employing Aspergillus niger and Aspergillus oryzae. Interestingly, A. oryzae produced 28 UmL−1 of α-amylase and the final residues were mycoproteins after 96 h. Furthermore, the strain removed 80–90% of total phosphorous, 90–99% of total nitrogen, and significantly lowered the COD, BOD, and TDS of urban wastewater. The data demonstrated that P. terebrans has substantial potential for resource recovery and could become a candidate for a wastewater-derived algal biorefinery.

Agroforestry offers multiple ecosystem services in degraded lateritic soils

Degradation of agricultural and forest lands is a global problem causing climate change, loss of biodiversity, ecosystem services, and environmental hazards. In the red and lateritic soils of the northeast, central and southern India, land degradation remains a major problem affecting the lives of millions of people. Agroforestry systems with appropriate combinations of arable crops, horticultural trees, and forest tree species are suggested as effective strategies to combat land degradation by restoring biodiversity and ecosystem services but the scientific evidence is lacking for red and lateritic soils of northeast India. In response, a forest deciduous tree species Gmelina [ Gmelina arborea Roxb.], a fruit tree mango [ Mangifera indica L.], and a legume crop pigeon pea [ Cajanus cajan (L.) Millsp.] were grown solely or in various combinations for ten years (July 2009 to June 2019) in the red and lateritic soil of West Bengal, India to evaluate their role in the restoration of degraded land and the potential for offering multiple ecosystems services. Eleven indicators were selected for evaluating the multifunctionality of ecosystem services having synergies between them. Results after ten years of field experiments revealed that the Gmelina -mango-pigeon pea agroforestry system has provided multiple ecosystem goods like edible seeds (pigeon pea), fruits (mango), fuelwood and timber (mango/ Gmelina ) sequentially, and was 2–3 times more profitable in terms of net present value compared to sole Gmelina or mango or pigeon pea. This system also offered greater climate resiliency with 1–2 times higher annual biomass production , thus offsetting greenhouse gases emission . The composite evaluation index demonstrated that this system offers the highest level of multifunctionality of multiple ecosystem services. Evidence from this long-term experimentation suggests that the crop-fruit tree-forest tree-based agroforestry system has the potential to restore the land productivity of the degraded red and lateritic soils and provide multiple ecosystem services to millions of people dependent on such land. This system could potentially be out-scaled in many other similar agroecological zones of the world. • A new comprehensive evaluation index of ecosystem services is proposed. • Agriculture, horticulture, forestry and agroforestry were compared with the new index. • Agroforestry shows the highest level of synergies of multiple ecosystem services. • It results in net positive C balance, high EROI, and improved biodiversity.

Adaptive potential and productivity of two Salix viminalis L. clonal varieties grown in North Central Bulgaria

Salix viminalis L. is a broadly cultivated willow species that has been intensively used for breeding purposes, particularly in selection of clones and hybrids for biomass production. The present study aimed to explore and compare growth and adaptability of two basket willow (Salix viminalis L.) clonal varieties - rubra and purpurea - at the specific edaphic and climate conditions and cultivation practice presented in an experimental plantation in North Central Bulgaria. The influence of spacing, genotype, root age and rotation on their productivity were also investigated and allometric relationships for non-destructive estimation of woody plant biomass were suggested. The trial plantation was established in the spring of 2018 as 4 sectors of a Nelder wheel plot with 15 nearly-square spacings, ranging from 0.25 to 9.80 m2 (40000–1020 plants per hectare). The two varieties were arranged in 4 four-spoke sectors (2 sectors per clone). Data collection took place from 2018 to 2020 and comprised 1- and 2-year rotations. The study showed that Salix viminalis var. rubra was more susceptible to desiccation-causing adverse climatic changes, poorly adapted to the specific conditions of the study site and gradually died out during the second and the third year. Salix viminalis var. purpurea exhibited steady survival rate (97 - 77%) and annual biomass productivity varying from 3 to 17 Mg/ha/year across the densities, sectors and years. During the first year of growth purpurea variety had a significantly higher plant weight and sprout number than rubra variety. Growing space affected positively the number of shoots and tree dendromass, and sprouting was reinforced by coppicing that doubled the shoot number during the subsequent rotation. This was reflected in the development of the stump-level allometric models that were differentiated according to rotation. The stump-level allometric model of higher predictive power was based on the main shoot length and shoot number. An exponential relationship to the breast-height shoot diameter was also suggested for biomass estimation of each sprout separately.

Allometric models for estimating aboveground biomass of young Norway spruce trees in the Western Carpathians, Slovakia

Abstract In the period of climate change, it is necessary to have biomass models for trees of all sizes to make precise estimations of biomass forest stocks to quantify carbon sequestration by forest cover. Therefore, we created allometric models of aboveground biomass in young Norway spruce (Picea abies [L.] Karst.) trees including main components, i.e. stem, branches and needles. The models used 200 sampled trees from 10 sites located in the central part of the Western Carpathians in Slovakia. The models, i.e. allometric regression relations implemented stem base diameter (diameter d0) and/or tree height. Moreover, using the derived allometric relations and a constant annual diameter increment of 10 mm, we calculated quasi-annual aboveground biomass production with regard to diameter d0. While stem had the largest contribution to aboveground biomass, followed by needles and branches, a different situation was revealed for the annual aboveground biomass production with the largest share of needles followed by stem and branches. Finally, we implemented the allometric models in a specific forest stand, where repetitive measurements were performed within 14 consecutive years. The results showed for example nearly 650 kg of the aboveground biomass per 102 m2 at the stand age of 10 years. The new biomass models can be applied to estimate the aboveground biomass stock in Norway spruce dominating stands in the Western Carpathians. Since the models are based on both diameter d0 and tree height a user can choose which variable is more suitable for particular conditions.

Persistence in a tropical transition zone? Sargassum forests alternate seasonal growth forms to maintain productivity in warming waters at the expense of annual biomass production

Macroalgal forests provide productivity and biomass that underpins the function of many coastal ecosystems globally. The phenology of forests is seasonally driven by environmental conditions, with the environment-productivity relationship understood for most coastlines of the world. Climatic transition zones, however, have characteristics of temperate and tropical regions, creating large fluctuations in environmental conditions, and potentially limiting productivity and the persistence of macroalgal forests. The response of a forest-forming, dimorphic seaweed (Sargassum hemiphyllum) to seasonal temperature and light conditions in a rapidly warming tropical-temperate transitional zone (Hong Kong) was quantified by measuring in situ growth, net primary productivity (NPP), respiration, and photosynthetic potential. These physiological responses of S. hemiphyllum were then experimentally tested in response to changing temperatures (16.5–27 °C) and irradiances (20, 110, and 300 μmol m−2 s−1) in laboratory mesocosms. In contrast to predictions, S. hemiphyllum demonstrated asynchronous NPP and growth patterns, with growth maximized in cooler conditions but, counter-intuitively, highest photosynthetic rates in summer after annual senescence and dormancy were established. This discrepancy between peak photosynthetic rates and growth may provide regional populations of S. hemiphyllum the ability to survive higher temperatures in the near future, resisting the predicted range shifts under ocean warming. In contrast, warming is likely to drive a shorter growth season, longer dormancy, and reduced annual biomass production in bi-phasic seaweeds inhabiting climatic transition zones, potentially reducing system-wide productivity of these algal forests.

Microalgae biomass production from cultivation in availability and limitation of nutrients: The technical, environmental and economic performance

Microalgae cultivation offers the potential to produce different biomass compositions while preventing pollution, treating waste and recovering resources. However, the energy, environmental and economic performance of the production of microalgae biomass should be advantageous compared to that of conventional biomass sources. The goal of this research was to quantify the performance of energy demand, carbon footprint and financial cost of microalgae biomass production in cultivation with availability and limitation of nutrients. The product system is composed of microalgae cultivation in open raceway ponds with carbon dioxide injection and harvesting with settling, filtration and centrifugation. The average annual biomass productivity in the cultivation was 18 g (m2 day)−1 in the base scenarios with availability (S1) and limitation (S2) of nitrogen and phosphorus, which was changed to 8.5 g (m2 day)−1 in S1LOWER and S2 LOWER and 25 g (m2 day)−1 in S1HIGHER and S2HIGHER. The methods used in this study were attributional life cycle assessment (LCA) for energy demand (Cumulative Energy Demand – CED) in Megajoule (MJ) and carbon footprint (IPCC-2021, Global Warming Potential 100 years) in kilogram of carbon dioxide equivalent (kg CO2eq) and techno-economic analysis (TEA) for financial cost in United States dollar (USD). The energy demand, carbon footprint and financial cost, respectively, in S1 were 10 MJ kg−1, 0.48 kg CO2eq kg−1 and 0.59 USD kg−1 for a dewatered biomass in total solids, while those varied by: +30%, +24% and +72% in S1LOWER; −11%, −8.9% and −19% in S1HIGHER; −38%, −46% and −15% in S2; −6.1%, −20% and +62% in S2LOWER; and −50%, −56% and −36% in S2HIGHER compared to S1. The largest contribution of energy demand and carbon footprint, respectively, in S1 was the fertilizer supply (52% and 61%), while in S2 it was the electricity supply (51% and 48%). The use of residual N and P and photovoltaic electricity supply were considered in the sensitivity analysis, which showed a potential to reduce up to 61% in energy demand, 84% in carbon footprint and 37% in financial cost compared to S1. Therefore, limiting nutrients and using nutrients from residual sources in cultivation along with providing electricity from a cleaner and affordable source are strategies for commodity production from microalgae biomass.

Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands

<h2>Summary</h2> Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m³ biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.

Biomass Quality Variations over Different Harvesting Regimes and Dynamics of Heavy Metal Change in Miscanthus lutarioriparius around Dongting Lake

Miscanthus lutarioriparius has a growing area of 100,000 ha and an annual biomass production of 1 Mt around Dongting Lake. However, due to serious soil pollution, there is a concern that the M. lutarioriparius biomass could have high heavy metal (HM) concentrations. This necessitates investigation of biomass quality to find the appropriate end use. Thus, this study aims to investigate the dynamics of HM elements in the M. lutarioriparius biomass and their impact on biomass quality across different growing areas and harvest times. We analyzed the HM concentrations in soil and biomass from 11 sites under different harvesting times (April, August and December). Results showed that Cd in soil samples was 9.43-fold higher than the national standards. The heavily polluted soil caused a high HM concentration in the biomass and the accumulation increased with the delayed harvest. The fresh young shoots in April met the food limitation for Cd and Cr, whereas Pb concentration was slightly higher than the threshold limit. The mature biomass from the southern part had higher Mn, Cd and Pb, but lower Cu, Zn and Cr concentrations than that from the eastern part. These results can provide guidance for guaranteeing the consistent quality of the M. lutarioriparius biomass for bio-based industry.

Effect of untreated and pretreated sugarcane molasses on growth performance of Haematococcus pluvialis microalgae in inorganic fertilizer and macrophyte extract culture media.

The growth of Haematococcus pluvialis in two alternative culture media NPK (10:10:10) and ME (macrophyte extract), under mixotrophic conditions using sugarcane molasses as a carbon source were evaluated for 28 days. The molasses was used in two different ways, in a native form (untreated) and a hydrolyzed (pretreated). Cell density of Haematococcus pluvialis in mixotrophic cultivation was higher in pretreated molasses. Growth rate was higher when pretreated molasses were employed in mixotrophic cultivation with NPK culture medium (k=0.5 7th growth day). Biomass, chlorophyll-a, conductivity and total inorganic nitrogen were not significantly different (p>0.05) during the experimental period for two mixotrophic cultivation and culture media. Protein contents of H. pluvialis biomass were higher in NPK culture medium with pretreated molasses (50% dry biomass). Annual biomass production was 520 kg-1 dry biomass with untreated molasses for two culture media, and 650 and 520 kg-1 dry biomass with pretreated molasses for NPK and ME culture media, respectively. The use of NPK and ME culture media in mixotrophic cultivation may be a new protocol for H. pluvialis cultivation due to the low cost and similar annual production.

An Assessment of the Potential Use of Forest Residues for the Production of Bio-Oils in the Urban-Rural Interface of Louisiana

Louisiana is endowed with forest resources. Forest wastes generated after thinning, land clearing, and logging operations, such as wood debris, tree trimmings, barks, sawdust, wood chips, and black liquor, among others, can serve as potential fuels for energy production in Louisiana. This paper aims to evaluate the potential annual volumes of forest wastes established on detailed and existing data on the forest structure in the rural-urban interface of Louisiana. It also demonstrates the state’s prospects of utilizing forest wastes to produce bio-oils. The data specific to the study was deduced from secondary data sources to obtain the annual average total residue production in Louisiana and estimate the number of logging residues available for procurement for bioenergy production. The total biomass production per year was modeled versus years by polynomial regression curve fitting using Microsoft Excel. Results of the model show that the cumulative annual total biomass production for 2025 and 2030 in Louisiana is projected to be 80000000 Bone Dry Ton (BDT) and 16000000 (BDT) respectively. The findings of the study depict that Louisiana has a massive biomass supply from forest wastes for bioenergy production. Thus, the potential for Louisiana to become an influential player in the production of bio-based products from forest residues is evident. The author recommends that future research can use Geographic Information Systems (GIS) to create maps displaying the potential locations and utilization centers of forest wastes for bioenergy production in the state.

Biomass productivity, forest stability, carbon balance, and soil transformation of agricultural land afforestation: A case study of suitability of native tree species in the submontane zone in Czechia

The increasing trend of afforestation is described in almost all European countries, however, the knowledge of the growth parameters of particular tree species on abandoned agricultural land is still incomplete. Therefore, the characteristics of young forest stands which are afforested with 5 native tree species (Norway spruce, European beech, English oak, sycamore maple, and small-leaved lime) were analyzed 14 years after afforestation. Afforestation had a positive influence on the soil physical characteristics with the highest porosity (58.2%) in spruce stands and water saturation (48.5%) in oak stands. Maple had the fastest initial growth and production with the highest mean annual increment (12.1 m3 ha−1 y-1) and total biomass production (200.8 t ha−1). Contrarily, the lowest production parameters were found in the beech stands with a low mean annual increment (1.4 m3 ha−1 y-1) and total biomass production (28.4 t ha−1). The most abundant carbon quantity in the soil and tree biomass together was sequestered in lime (125.1 t ha−1) followed by maple stands (124.5 t ha−1). On average, the total carbon balance was 67.4% stored in the tree biomass, and 32.6% in the soil for tree species evaluated together. The amount of carbon sequestered in the soil will increase in the following years in relation to overlying humus development, incorporation of soil organic carbon in the mineral soil horizons, as well as with tree biomass production. The study demonstrated a significant difference in growth potential, biomass production, soil transformation and carbon sequestration in native tree species stands established on former agricultural lands. Most importantly, the differences in carbon sequestration should be considered in future agricultural land afforestation to mitigate the negative impact of global climate change.

Global Mercury Assimilation by Vegetation.

Assimilation of mercury (Hg) by vegetation represents one of the largest global environmental Hg mass fluxes. We estimate Hg assimilation by vegetation globally via a bottom-up scaling approach using tissue Hg concentrations synthesized from a comprehensive database multiplied by respective annual biomass production (NPP). As global annual NPP is close to annual vegetation die-off, Hg mass associated with global NPP approximates the transfer of Hg from plants to soils, which represents an estimate of vegetation-mediated atmospheric deposition. Annual vegetation assimilation of Hg from combined atmospheric and soil uptake is estimated at 3062 ± 607 Mg yr-1, which is composed of 2491 ± 551 Mg yr-1 from aboveground tissue uptake and 571 ± 253 Mg yr-1 from root uptake. Assimilation of atmospheric Hg amounts to 2422 ± 483 Mg yr-1 when considering aboveground tissues only. Atmospheric assimilation increases to 2705 ± 504 Mg yr-1 when considering that root Hg may be partially derived from prior foliar uptake and transported internally to roots. Estimated atmospheric Hg assimilation by vegetation is 54-137% larger than the current model and litterfall estimates, largely because of the inclusion of lichens, mosses, and woody tissues in deposition and all global biomes. Belowground, about 50% of root Hg was taken up from soils with currently unknown ecological and biogeochemical consequences.

Strategies to Produce Cost-Effective Third-Generation Biofuel From Microalgae

Third-generation biofuel produced from microalgae is a viable solution to global energy insecurity and climate change. Despite an annual current global algal biomass production of 38 million litres, commercialization confronts significant economic challenges. However, cost minimization strategies, particularly for microalgae cultivation, have largely been excluded from recent studies. Therefore, this review provides essential insights into the technologies and economics of cost minimization strategies for large-scale applications. Cultivation of microalgae through aquafarming, in wastewater, or for biogas upgrading, and co-production of value-added products (VAPs) such as photo-bioreactors, protein, astaxanthin, and exopolysaccharides can drastically reduce biodiesel production costs. For instance, the co-production of photo-bioreactors and astaxanthin can reduce the cost of biodiesel production from $3.90 to $0.54 per litre. Though many technical challenges need to be addressed, the economic analysis reveals that incorporating such cost-effective strategies can make the biorefinery concept feasible and profitable. The cost of producing microalgal biodiesel can be lowered to $0.73kg−1dry weight when cultivated in wastewater or $0.54L−1when co-produced with VAPs. Most importantly, access to co-product markets with higher VAPs needs to be encouraged as the global market for microalgae-based VAPs is estimated to rise to $53.43 billion in 2026. Therefore, policies that incentivize research and development, as well as the production and consumption of microalgae-based biodiesel, are important to reduce the large gap in production cost that persists between biodiesel and petroleum diesel.

Lipid extraction from some seaweeds and evaluation of its biodiesel production

The present study evaluated the efficiency of seaweeds collected from Abu Qir Bay, Alexandria, Egypt, as a feedstock for biodiesel. A total of 15 macroalgal species were collected overall in the four seasons. The highest seasonal biomass production of 652.1 and 626.3 g m −2 was recorded with Chaetomorpha linum and Ulva compressa in autumn and spring, respectively. While the highest annual biomass production was detected in Ulva fasciata (1056.8 g m −2 ). Lipid content varied among species, with the highest value of 14.66% and 9.94% dw in U. fasciata and U. compressa during spring, which resulted in the highest annual lipid productivity of 67.4 and 63.3 g m −2 , respectively. Palmitic acid (C16:0) showed the highest value among all fatty acids (1.12–19.62 mg g− 1 dw) in all studied species. The biodiesel characteristics of all algae species tested are in agreement with the values of international standards. Overall, the present study recommended U. compressa and U. fasciata as a promising biodiesel feedstock due to the relatively higher lipid productivity and FAMEs characteristics that comply with the international standards and high net energy output that reached 1.24 and 1.30 GJ ton −1 , respectively. • Chaetomorpha linum and Ulva compressa recorded the highest seasonal biomass production. • Possible exploring of 15 macroalgae as biodiesel feedstock species. • Palmitic acid (C16:0) showed the highest proportion in all studied seaweed species. • Ulva compressa and Ulva fasciata are a promising biodiesel feedstock.

Natural soil microbiome variation affects spring foliar phenology with consequences for plant productivity and climate-driven range shifts.

Identifying the potential for natural soil microbial communities to predictably affect complex plant traits is an important frontier in climate change research. Plant phenology varies with environmental and genetic factors, but few studies have examined whether the soil microbiome interacts with plant population differentiation to affect phenology and ecosystem function. We compared soil microbial variation in a widespread tree species (Populus angustifolia) with different soil inoculum treatments in a common garden environment to test how the soil microbiome affects spring foliar phenology and subsequent biomass growth. We hypothesized and show that soil bacterial and fungal communities vary with tree conditioning from different populations and elevations, that this soil community variation influences patterns of foliar phenology and plant growth across populations and elevation gradients, and that transferring lower elevation plant genotypes to higher elevation soil communities delayed foliar phenology, thereby shortening the growing season and reducing annual biomass production. Our findings show the importance of plant-soil interactions that help shape the timing of tree foliar phenology and productivity. These geographic patterns in plant population×microbiome interactions also broaden our understanding of how soil communities impact plant phenotypic variation across key climate change gradients, with consequences for ecosystem functioning.

Development and characterization of a Napier grass (Cenchrus purpureus Schumach) mapping population for flowering‐time‐ and biomass‐related traits reveal individuals with exceptional potential and hybrid vigor

AbstractNapier grass is a tropical perennial C4 grass with superior biomass yield and quality. It is an important forage crop and a promising feedstock for lignocellulosic biofuel production. However, precise phenotyping and genotyping data to support the molecular breeding of Napier grass are scarce. A Napier grass F1 mapping population (segregating pseudo‐F2 population) was generated by hybridizing genetically distant parents (N190 × N122) with contrasting flowering‐time‐ and biomass‐related traits. True F1 hybrids were confirmed with a simple sequence repeat marker, vegetatively propagated, and phenotyped in replicate field plots for 2 years (2 harvests per year) in Citra, FL, USA (29.40N). Near‐normal distributions were observed for flowering date, plant height, number of tillers, stem diameter, and leaf width, confirming the quantitative nature of these traits. The annual dry biomass yield of F1 hybrids varied between 21.0 and 41.1 t ha−1. The highest‐yielding F1 hybrids showed remarkable hybrid vigor exceeding the annual biomass production of the highest‐yielding parental accession (26.9 t ha−1) by 52% and the biomass yield of the control “Merkeron” cultivar (29.2 t ha−1) by 41% over 2 years. F1 hybrids with delayed flowering time along with significantly increased biomass yield were also identified. Late‐flowering accessions allowed maximum biomass harvest before formation and dispersal of seeds, reducing invasion risk. The developed mapping population will be an excellent resource for identifying quantitative trait loci and candidate genes for flowering‐ and biomass‐related traits in Napier grass that will accelerate the improvement of this non‐domesticated bioenergy crop.

Climate-Simulated culturing suggests high microalgal biomass and oil productivities in most of the South American continent.

Current production costs of microalgal biomass indicate that only highly-productive cultivation facilities will approach commercial feasibility. Geographical site selection for siting those facilities is critical for achieving target productivities. The aim of this study was to provide a semi-empirical estimation of microalgal biomass and lipids productivity in South America. Simulated-climate was programed in environmental photobioreactors (Phenometrics) for a simulation of cultivation in open raceway ponds at different geographical sites. The mean annual South American biomass productivity of 20-cm deep ponds was 12 ± 4g · m- 2 · d-1 . The most productive regions were clustered in the subtropical and tropical regions of the continent. Fortaleza (Brazil) showed a low seasonality and a high annual mean productivity of 23g · m-2 · d-1 in 5-cm deep ponds, closely approaching the productivity target. Lipids accumulation and productivity in Fortaleza showed a high microalgal oil accumulation up to 46% (w/w) and a maximum oil productivity of 5g · m-2 · d-1 for biomass containing around 20% lipids (w/w). This study provides the first semi-empirical estimation of microalgal productivity in South America and supports a high potential of a vast region of the continent.

Optimization of ecosystems services for sustainable coffee production under changing climate

Legume cover crops have previously been evaluated for green manure, weed control and soil moisture conservation, this study includes further evaluation of biomass of the legume fodder. Our research was to compare soil nutrients and moisture concentration at different times in the treatment plots in the coffee plantation after the establishment of a desmodium legume cover crop with quantification of the resulting biomass as fodder for livestock. This case study conducted at the University of Nairobi coffee plantation evaluating different weed control methods in coffee using hand weeding, glyphosate (1.0 kg ha-¹ of acid equivalent) based herbicide and desmodium spp legume cover crop compared weeding costs and implications to farmers’ incomes in coffee production. Using completely Randomized Block Design 3 treatments replicated 3 times were analyzed for the annual weeding labour costs, soil nutrients, soil moisture and biomass production. Statistical analysis of soil moisture content and nutrients was evaluated among the treatments. Results indicated that coffee intercropped with desmodium had higher moisture retention of 36 % on average being higher than other treatment and desmodium legume fresh biomass production was extrapolated to 17,000 kgs per hectare per year. Desmodium spp planted was able to establish providing groundcover (90%) 18 weeks after planting inhibiting weed growth thus reducing the need for weeding as well as conserve soil moisture. There were significant savings on the cost of manual weeding with additional earnings or savings of 750 $ US from sales or utilization of the desmodium fodder per hectare. The study concludes that cover crops can enhance farmers’ resilience to changing climate utilizing the same size of land while enhancing output and increasing revenue. Policymakers need to realign extension services to introduce legume cover crops in coffee production to reduce the labour costs and the high doses of synthetic fertilizers which emit