Aim of study: To analyze the environmental and economic performance of a multifunctional poplar plantation (MPP), which was managed to produce timber for sawn wood and chips for bioenergy. Area of ...study: The plantation was located in Southern Spain producing roundwood and woodchips (from tops and branches). Material and methods: The life cycle assessment (LCA) methodology was chosen to perform the environmental impact assessment from a cradle-to-gate perspective. Capital goods, including machinery-manufacturing processes, were included. One oven dry tonne (odt) of forest biomass was chosen as functional unit. The economic analysis was performed using present costs and common indicators: net present value (NPV) and internal rate of return (IRR). Main results: The harvest operations are the most environmental impacting subsystem and cultivation the costliest. Chipping was the process contributing the most to the environmental burden. The use of fertilizers, within the cultivation subsystem, had a notable impact on certain midpoint categories. In terms of climate change potential, 1 odt of delivered wood chips generated 64.1 kg CO2-eq. When considering the whole system (including the roundwood fraction), this value was 45.2 kg CO2-eq odt-1. MPP was hardly profitable with land rental and irrigation being the most expensive items. NPV, including harvesting and transport subsystems, was 1,582 € ha-1, while IRR reached 6.3%. Research highlights: Our results allow to identify the costliest operations and those with the greatest impact to improve the system. Finally, these figures can be compared with other crop alternatives such us poplar short rotation coppice (SRC).
Land use efficiency can be maximized if an intercropping system is utilized to produce switchgrass (Panicum virgatum L.) biomass within the alleys between hybrid poplar trees (Populus spp.). ...Information is limited on switchgrass production and intercropping system in the Pacific Northwest of U.S. The objectives of this study were to evaluate the effects of hybrid poplar trees on switchgrass yield and forage quality and to determine the land use efficiency in an intercropping system under irrigation. Three cultivars of switchgrass (‘Kanlow’, ‘Blackwell’, and ‘Trailblazer’) were planted in the alleys between hybrid poplar trees (Clones: OP367 and PC4) at the Greenwood Resources, Boardman, OR in 2011. Switchgrass growth was negatively influenced by hybrid poplar trees with mean leaf area index, tiller density, and switchgrass dry matter (DM) yield in the monoculture and intercropped plots equal to 4.9 and 1.7, 383 and 69 tillers m−2, and 15 and 4 Mg ha−1, respectively, in the third year of this study. The 3-year cumulative switchgrass monoculture, switchgrass intercropping, and tree yield was 47.7, 21.5, and 58.5 Mg ha−1. As a result, cumulative land equivalent ratio during the three years of the study was 1.45 in intercropped compared to 1.0 in monoculture plots. This indicates that 45% more land would be required in monoculture system to produce the same amount of DM produced in the intercropping system. This study revealed that, despite the reduced switchgrass growth under hybrid poplar trees, intercropping hybrid poplar and switchgrass can improve land use efficiency for biomass production.
•Effects of intercropping hybrid poplar and switchgrass on yield, forage quality, and land use efficiency were proposed.•Switchgrass growth decreased in terms of leaf area index, tiller density, and dry matter yield.•Land use efficiency was greater in the intercropped than monoculture plots regardless of the reduced switchgrass growth.
Abscisic acid (ABA) is a well known stress hormone regulating drought adaptation of plants. Here, we hypothesised that genetic engineering of genes involved in ABA stress signalling and photoperiodic ...regulation affected drought resistance by trade-off with biomass production in perennial poplar trees.
We grew Populus tremula × tremuloides wild-type (T89) and various transgenic lines (two transformation events of 35S::abi1-1, 35S::RCAR, RCAR:RNAi, 35S::ABI3, 35S::AREB3, 35S::FDL1, FDL1:RNAi, 35S::FDL2 and FDL2:RNAi) outdoors and exposed them to drought in the second growth period.
After the winter, the surviving lines showed a huge variation in stomatal conductance, leaf size, whole-plant leaf area, tree height, stem diameter, and biomass. Whole-plant leaf area was a strong predictor for woody biomass production. The 35S::AREB3 lines were compromised in biomass production under well irrigated conditions compared with wild-type poplars but were resilient to drought. ABA signalling regulated FDL1 and FDL2 expression under stress. Poplar lines overexpressing FDL1 or FDL2 were drought-sensitive; they shed leaves and lost root biomass, whereas the FDL RNAi lines showed higher biomass allocation to roots under drought.
These results assign a new function in drought acclimation to FDL genes aside from photoperiodic regulation. Our results imply a critical role for ABA-mediated processes in balancing biomass production and climate adaptation.
Here, we describe a method for the combined metabolomic, proteomic, transcriptomic and genomic analysis from one single sample as a major step for multilevel data integration strategies in systems ...biology. While extracting proteins and DNA, this protocol also allows the separation of metabolites into polar and lipid fractions, as well as RNA fractionation into long and small RNAs, thus allowing a broad range of transcriptional studies. The isolated biomolecules are suitable for analysis with different methods that range from electrophoresis and blotting to state‐of‐the‐art procedures based on mass spectrometry (accurate metabolite profiling, shot‐gun proteomics) or massive sequencing technologies (transcript analysis). The low amount of starting tissue, its cost‐efficiency compared with the utilization of commercial kits, and its performance over a wide range of plant, microbial, and algal species such as Chlamydomonas, Arabidopsis, Populus, or Pinus, makes this method a universal alternative for multiple molecular isolation from plant tissues.
Nitrous oxide (N₂O) is a major greenhouse gas and cultivated soils are the most important anthropogenic source. N₂O production and consumption are known to occur at depths below the A or A
p horizon, ...but their magnitude in situ is largely unknown. At a site in SW Michigan, USA, we measured N₂O concentrations at different soil depths and used diffusivity models to examine the importance of depth-specific production and consumption. We also tested the influence of crop and management practices on subsurface N₂O production in (1) till versus no-till, (2) a nitrogen fertilizer gradient, and (3) perennial crops including successional vegetation. N₂O concentrations below 20 cm exceeded atmospheric concentrations by up to 900 times, and profile concentrations increased markedly with depth except immediately after fertilization when production was intense in the surface horizon, and in winter, when surface emissions were blocked by ice. Diffusivity analysis showed that N₂O production at depth was especially important in annual crops, accounting for over 50% of total N₂O production when crops were fertilized at recommended rates. At nitrogen fertilizer rates exceeding crop need, subsurface N₂O production contributed 25–35% of total surface emissions. Dry conditions deepened the maximum depth of N₂O production. Tillage did not. In systems with perennial vegetation, subsurface N₂O production contributed less than 20% to total surface emissions. Results suggest that the fraction of total N₂O produced in subsurface horizons can be substantial in annual crops, is low under perennial vegetation, appears to be largely controlled by subsurface nitrogen and moisture, and is insensitive to tillage.
Nitrous oxide (N2O) is a prime greenhouse gas and cultivated soils are the most important anthropogenic source. N2O production and consumption are known to occur at depths below the A or Ap horizon, ...but their magnitude in situ is largely unknown. At a site in SW Michigan, USA, we measured N2O concentrations at different soil depths and used diffusivity models to examine the importance of depth-specific production and consumption. Additionally, we tested the influence of crop and management practices on subsurface N2O production in (1) till versus no-till, (2) a nitrogen fertilizer gradient, and (3) perennial crops including successional vegetation. N2O concentrations below 20 cm exceeded atmospheric concentrations by up to 900 times, and profile concentrations increased markedly with depth except immediately after fertilization when production was intense in the surface horizon, and in winter, when surface emissions were blocked by ice. Diffusivity analysis showed that N2O production at depth was especially important in annual crops, accounting for over 50% of total N2O production when crops were fertilized at recommended rates. At nitrogen fertilizer rates exceeding crop need, subsurface N2O production contributed 25–35% of total surface emissions. Dry conditions deepened the maximum depth of N2O production. Tillage did not. In systems with perennial vegetation, subsurface N2O production contributed less than 20% to total surface emissions. Results suggest that the fraction of total N2O produced in subsurface horizons can be substantial in annual crops, is low under perennial vegetation, appears to be largely controlled by subsurface nitrogen and moisture, and is insensitive to tillage.
Riparian cottonwood forests in dry regions of western North America do not typically receive sufficient growing season precipitation to completely support their relatively high transpiration ...requirements. Water used in transpiration by riparian ecosystems must include alluvial groundwater or water stored in the potentially large reservoir of the unsaturated soil zone. We used the stable oxygen and hydrogen isotope composition of stem xylem water to evaluate water sources used by the dominant riparian cottonwood (Populus spp.) trees and shrubs (Shepherdia argentea and Symphoricarpos occidentalis) in Lethbridge, Alberta, during 3 years of contrasting environmental conditions. Cottonwoods did not exclusively take up alluvial groundwater but made extensive use of water sourced from the unsaturated soil zone. The oxygen and hydrogen isotope compositions of cottonwood stem water did not strongly overlap with those of alluvial groundwater, which were closely associated with the local meteoric water line. Instead, cottonwood stem water δ18O and δ2H values were located below the local meteoric water line, forming a line with a low slope that was indicative of water exposed to evaporative enrichment of heavy isotopes. In addition, cottonwood xylem water isotope compositions had negative values of deuterium excess (d‐excess) and line‐conditioned (deuterium) excess (lc‐excess), both of which provided evidence that water taken up by the cottonwoods had been exposed to fractionation during evaporation. The shrub species had lower values of d‐excess and lc‐excess than had the cottonwood trees due to shallower rooting depths, and the d‐excess values declined during the growing season, as shallow soil water that was taken up by the plants was exposed to increasing, cumulative evaporative enrichment. The apparent differences in functional rooting pattern between cottonwoods and the shrub species, strongly influenced the ratio of net photosynthesis to stomatal conductance (intrinsic water‐use efficiency), as shown by variation among species in the δ13C values of leaf tissue.
Analyses of stem water stable isotope composition were used to identify water taken up by plants. The Populus trees and Shepherdia and Symphoricarpos shrubs had contrasting functional rooting depths as illustrated by the different seasonal patterns of change in deuterium excess values, which indicated greater shallow soil water use by the shrub species.
Chelant-enhanced phytoextraction of heavy metals is an emerging technological approach for a non-destructive remediation of contaminated soils. The main objectives of this study were (i) to assess ...the extraction efficiency of two different synthetic chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS)) for desorbing Pb from two contaminated agricultural soils originating from a mining and smelting district and (ii) to assess the phytoextraction efficiency of maize (
Zea mays) and poplar (
Populus sp.) after EDTA application. EDTA was more efficient than EDDS in desorbing and complexing Pb from both soils, removing as much as 60% of Pb. Maize exhibited better results than poplar when extracting Pb from the more acidic (pH
∼
4) and more contaminated (up to 1360
mg
Pb
kg
−1) agricultural soil originating from the smelting area. On the other hand, poplars proved to be more efficient when grown on the near-neutral (pH
∼
6) and less contaminated (up to 200
mg
Pb
kg
−1) agricultural soil originating from the mining area. Furthermore, the addition of EDTA led to a significant increase of Pb content especially in poplar leaves, proving a strong translocation rate within the poplar plants.
On the basis of the compiled database in a number of 413 sample plots with determinations of forest biomass of the genus Populus sp. on the territory of Eurasia from France to southern China and ...Japan statistically significant transcontinental decreasing of stem, above ground and total biomass as in the direction from northern temperate to subequatorial zonal belt and in the direction from the Atlantic and Pacific coasts to the continentality pole in Siberia is established. Unlike wood story, understory biomass in these directions has not decreased, and increasing. The root: shoot ratio increases in the range between northern temperate and subequatorial zonal belts from 15 to 32% and within the southern temperate zone it monotonically increases from 5% on the oceanic coasts to 40% near continentality pole. The ratio of understory to wood story biomass increases from 0.3 to 1.6% ranging from northern temperate to subequatorial zonal belt, and within the south temperate zone it monotonically increases from zero values near Atlantic and Pacificcoasts, approaching the level of 40% near the continentality pole. The results can be useful in the management of biosphere functions of forests, what is important when implementing activities on climate stabilization, as well as in the validation of the results of the simulations for assessing the carbon-depositing forest capacity.
Remote sensing of phenology is adopted as the practice in greenery monitoring. Now research is turned towards the fusion of data from various sensors to fill in the gap in time series and allow ...monitoring of pests and disturbances. Poplar species were monitored for the determination of the best approach for detecting phenology and disturbances. With the adjustments that include a choice of indices, wavelengths, and a setup, a multispectral camera may be used to calibrate satellite images. The image processing pipeline included different denoising and interpolation methods. The correlation of the changes in a signal of top and lateral imaging proved that the contribution of the whole canopy is reflected in satellite images. Normalized difference vegetation index (NDVI) and normalized difference red edge index (NDRE) successfully distinguished among phenophases and detected leaf miner presence, unlike enhanced vegetation index (EVI). Changes in the indices were registered before, during, and after the development of the disease. NDRE is the most sensitive as it distinguished among the different intensities of damage caused by pests but it was not able to forecast its occurrence. An efficient and accurate system for detection and monitoring of phenology enables the improvement of the phenological models’ quality and creates the basis for a forecast that allows planning in various disciplines.
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