• Authors:
    • Pereira, G. T.
    • Panosso, A. R.
    • Cerri, C. E. P.
    • Bicalho, E. S.
    • Teixeira, D. D. B.
    • La Scala, N.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 167
  • Year: 2013
  • Summary: The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60 m x 60 m containing 127 points with minimum separation distances from 0.5 to 10 m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28 +/- 0.11 mu mol m(-2) s(-1) (F197) to 1.82 +/- 0.07 mu mol m(-2) s(-1) (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity.
  • Authors:
    • Tausz, M.
    • Norton, R. M.
    • Cane, K.
    • Tausz-Posch, S.
    • Thilakarathne, C. L.
    • Seneweera, S.
  • Source: Functional Plant Biology
  • Volume: 40
  • Issue: 2
  • Year: 2013
  • Summary: In order to investigate the underlying physiological mechanism of intraspecific variation in plant growth and yield response to elevated CO2 concentration [CO2], seven cultivars of spring wheat (Triticum aestivum L.) were grown at either ambient [CO2] (similar to 384 mu mol mol(-1)) or elevated [CO2] (700 mu mol mol(-1)) in temperature controlled glasshouses. Grain yield increased under elevated[CO2] by an average of 38% across all seven cultivars, and this was correlated with increases in both spike number (productive tillers) (r = 0.868) and aboveground biomass (r = 0.942). Across all the cultivars, flag leaf photosynthesis rate (A) increased by an average of 57% at elevated [CO2]. The response of A to elevated [CO2] ranged from 31% (in cv. H45) to 75% (in cv. Silverstar). Only H45 showed A acclimation to elevated [CO2], which was characterised by lower maximum Rubisco carboxylation efficiency, maximum electron transport rate and leaf N concentration. Leaf level traits responsible for plant growth, such as leaf mass per unit area (LMA), carbon (C), N content on an area basis ([N](LA)) and the C : N increased at elevated [CO2]. LMA stimulation ranged from 0% to 85% and was clearly associated with increased [N](LA). Both of these traits were positively correlated with grain yield, suggesting that differences in LMA play an important role in determining the grain yield response to elevated [CO2]. Thus increased LMA can be used as a new trait to select cultivars for a future [CO2]-rich atmosphere.
  • Authors:
    • Thomas,Amy R. C.
    • Bond,Alan J.
    • Hiscock,Kevin M.
  • Source: Global Change Biology Bioenergy
  • Volume: 5
  • Issue: 3
  • Year: 2013
  • Summary: Reduction in energy sector greenhouse gas GHG emissions is a key aim of European Commission plans to expand cultivation of bioenergy crops. Since agriculture makes up 1012% of anthropogenic GHG emissions, impacts of land-use change must be considered, which requires detailed understanding of specific changes to agroecosystems. The greenhouse gas (GHG) balance of perennials may differ significantly from the previous ecosystem. Net change in GHG emissions with land-use change for bioenergy may exceed avoided fossil fuel emissions, meaning that actual GHG mitigation benefits are variable. Carbon (C) and nitrogen (N) cycling are complex interlinked systems, and a change in land management may affect both differently at different sites, depending on other variables. Change in evapotranspiration with land-use change may also have significant environmental or water resource impacts at some locations. This article derives a multi-criteria based decision analysis approach to objectively identify the most appropriate assessment method of the environmental impacts of land-use change for perennial energy crops. Based on a literature review and conceptual model in support of this approach, the potential impacts of land-use change for perennial energy crops on GHG emissions and evapotranspiration were identified, as well as likely controlling variables. These findings were used to structure the decision problem and to outline model requirements. A process-based model representing the complete agroecosystem was identified as the best predictive tool, where adequate data are available. Nineteen models were assessed according to suitability criteria, to identify current model capability, based on the conceptual model, and explicit representation of processes at appropriate resolution. FASSET, ECOSSE, ANIMO, DNDC, DayCent, Expert-N, Ecosys, WNMM and CERES-NOE were identified as appropriate models, with factors such as crop, location and data availability dictating the final decision for a given project. A database to inform such decisions is included.
  • Authors:
    • Venkateswarlu, B.
    • Rao,V. U. M.
  • Source: Climate Change Modeling, Mitigation, and Adaptation
  • Year: 2013
  • Authors:
    • Wei, H.
    • Broeckx, L. S.
    • Verlinden, M. S.
    • Ceulemans, R.
  • Source: Plant Soil
  • Volume: 369
  • Issue: 1-2
  • Year: 2013
  • Summary: In this study we quantified the annual soil CO2 efflux (annual SCE) of a short rotation coppice plantation in its establishment phase. We aimed to examine the effect of former (agricultural) land use type, inter-row spacing and genotype. Annual SCE was quantified during the second growth year of the establishment rotation in a large scale poplar plantation in Flanders. Automated chambers were distributed over the two former land use types, the two different inter-row spacings and under two poplar genotypes. Additional measurements of C, N, P, K, Mg, Ca and Na concentrations of the soil, pH, bulk density, fine root biomass, microbial biomass C, soil mineralization rate, distance to trees and tree diameters were performed at the end of the second growth year. Total carbon loss from soil CO2 efflux was valued at 589 g m(-2) yr(-1). Annual SCE was higher in former pasture as compared to cropland, higher in the narrow than in the wider inter-row spacings, but no effect of genotype was found. Spatial differences in site characteristics are of great importance for understanding the effect of ecosystem management and land use change on soil respiration processes and need to be taken into account in modeling efforts of the carbon balance.
  • Authors:
    • McManus, M. C.
    • Whittaker, C.
    • Smith, P.
  • Source: Environmental Modelling & Software
  • Volume: 46
  • Issue: August
  • Year: 2013
  • Summary: In light of concerns over climate change and the need for national inventories for greenhouse gas reporting, there has been a recent increase in interest in the 'carbon foot printing' of products. A number of LCA-based carbon reporting tools have been developed in both the agricultural and renewable energy sectors, both of which follow calculation methodologies to account for GHG emissions from arable cropping. A review was performed to compare 11 existing greenhouse gas (GHG) accounting tools produced in order to calculate emissions from arable crops, either for food or bioenergy production in the UK, and a multi-criteria-analysis was performed to test their relative strengths and weaknesses. Tools designed for farm-based accounting achieved a higher 'user-friendliness' score, however bioenergy-based tools performed better in the overall level of information provided in the results, transparency and the comprehensiveness of emission sources included in the calculations. A model dataset for UK feed wheat was used to test the GHG emissions calculated by each tool. The results showed large differences, mainly due to how greenhouse gas emissions from fertiliser manufacture and application are accounted fat Overall, the Cool Farm Tool (Hillier et al., 2011) was identified as the highest ranking tool that is currently available in the public domain. The differences in the results between the tools appear to be due to the goal and scope, the system boundaries and underlying emission factor data. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.
  • Authors:
    • Jamont,Marie
    • Piva,Guillaume
    • Fustec,Joelle
  • Source: Plant and Soil
  • Volume: 371
  • Issue: 1-2
  • Year: 2013
  • Summary: Legume-brassica intercrops may help to reduce N fertilizer input. We tested whether (i) intercropping with faba bean can improve N status of rapeseed, and (ii) root complementarity and/or N transfer is involved in such performance. Pre-germinated rapeseed and faba bean were grown either together or in monospecific rhizotrons (2 plants per rhizotron). Root growth was recorded. N rhizodeposition of the crops and N transferred between species were assessed using a N-15 stem-labelling method. Intercropped rapeseeds accumulated 20 % higher amounts of N per plant than monocultures. Up to 32 days after sowing, root distribution in the rhizotrons was favourable to physical sharing of the soil N: 64 % of faba bean root length was located in the upper part, as 70 % was in the lower part for rapeseed. At late flowering of the faba bean (52 days after sowing), N rhizodeposition of the two crops were similar and reached 8 to 9 % of the plant N. N transferred from the faba bean to the rapeseed was similar to that transferred from the rapeseed to the faba bean. Niche complementarity benefits more intercropped rapeseed than net N fluxes between species in the early growth.
  • Authors:
    • Moriondo,M.
    • Jones,G. V.
    • Bois,B.
    • Dibari,C.
    • Ferrise,R.
    • Trombi,G.
    • Bindi,M.
  • Source: Climatic Change
  • Volume: 119
  • Issue: 3-4
  • Year: 2013
  • Summary: This research simulates the impact of climate change on the distribution of the most important European wine regions using a comprehensive suite of spatially informative layers, including bioclimatic indices and water deficit, as predictor variables. More specifically, a machine learning approach (Random Forest, RF) was first calibrated for the present period and applied to future climate conditions as simulated by HadCM3 General Circulation Model (GCM) to predict the possible spatial expansion and/or shift in potential grapevine cultivated area in 2020 and 2050 under A2 and B2 SRES scenarios. Projected changes in climate depicted by the GCM and SRES scenarios results in a progressive warming in all bioclimatic indices as well as increasing water deficit over the European domain, altering the climatic profile of each of the grapevine cultivated areas. The two main responses to these warmer and drier conditions are 1) progressive shifts of existing grapevine cultivated area to the north-northwest of their original ranges, and 2) expansion or contraction of the wine regions due to changes in within region suitability for grapevine cultivation. Wine regions with climatic conditions from the Mediterranean basin today (e.g., the Languedoc, Provence, Ctes Rhne M,ridionales, etc.) were shown to potentially shift the most over time. Overall the results show the potential for a dramatic change in the landscape for winegrape production in Europe due to changes in climate.
  • Authors:
    • Poggio,Laura
    • Gimona,Alessandro
    • Brewer,Mark J.
  • Source: Geoderma
  • Volume: 209
  • Year: 2013
  • Summary: Knowledge of soil properties with complete area coverage is needed for policy-making, land resource management, and monitoring environmental impacts. Remote sensing offers possibilities to support Digital Soil Mapping, especially in data-poor regions. The aim of this work was to test the potential of time-series of MODIS (Moderate Resolution Imaging Spectroradiometer) vegetation and drought indices to provide relevant information to model topsoil properties in a Boreal-Atlantic region (Scotland) focussing on differentiation between soils with high and soils with low organic matter contents. For each of the three considered years, 345 MODIS data sets were included in the exploratory analysis; 15 data products for 23 dates (bi-weekly) per year. Terrain parameters derived from Shuttle Radar Topography Mission were also included. A methodology was implemented to exploit fully the high number of covariates, to identify the band, index or product that best correlates with the soil property of interest. In particular the proposed approach i. relies on freely globally available data-sets; ii. uses statistical criteria to select the combination of covariates providing the highest predictive capability, among the data considered and available; iii. deals with both continuous (using Generalized Additive Models, GAMs) and multinomial categorical (using Random Trees) types of variables; iv. takes into account fully the spatial autocorrelation of the data; v. provides estimates of the spatial uncertainty for each pixel; and vi. is computationally efficient when compared with methods such as forward stepwise. The models fitted show a fairly good agreement with existing data sets, presenting a consistent spatial pattern. The use of MODIS data as covariates increased the predictive capabilities of GAMs using only terrain parameters. The misclassification error for organic matter classes was between 25 and 35%. The assessment provided of the spatial uncertainty of the modelled values can be used in further modelling and in the assessment of consequences of climate-change and trade-off in land use changes. This approach can contribute to improving our understanding and modelling of soil processes and function over large, and relatively sparsely sampled, areas of the world. (C) 2013 Elsevier B.V. All rights reserved.
  • Authors:
    • Bateman,Ian J.
    • Harwood,Amii R.
    • Mace,Georgina M.
    • Watson,Robert T.
    • Abson,David J.
    • Andrews,Barnaby
    • Binner,Amy
    • Crowe,Andrew
    • Day,Brett H.
    • Dugdale,Steve
    • Fezzi,Carlo
    • Foden,Jo
    • Hadley,David
    • Haines-Young,Roy
    • Hulme,Mark
    • Kontoleon,Andreas
    • Lovett,Andrew A.
    • Munday,Paul
    • Pascual,Unai
    • Paterson,James
    • Perino,Grischa
    • Sen,Antara
    • Siriwardena,Gavin
    • van Soest,Daan
    • Termansen,Mette
  • Source: Science
  • Volume: 341
  • Issue: 6141
  • Year: 2013
  • Summary: Landscapes generate a wide range of valuable ecosystem services, yet land-use decisions often ignore the value of these services. Using the example of the United Kingdom, we show the significance of land-use change not only for agricultural production but also for emissions and sequestration of greenhouse gases, open-access recreational visits, urban green space, and wild-species diversity. We use spatially explicit models in conjunction with valuation methods to estimate comparable economic values for these services, taking account of climate change impacts. We show that, although decisions that focus solely on agriculture reduce overall ecosystem service values, highly significant value increases can be obtained from targeted planning by incorporating all potential services and their values and that this approach also conserves wild-species diversity.