• Authors:
    • Sastre,C. M.
    • Gonzalez-Arechavala,Y.
    • Santos,A. M.
  • Source: Applied Energy
  • Volume: 154
  • Year: 2015
  • Summary: This paper aims to provide more accurate results in the life cycle assessment (LCA) of electricity generation from wheat straw grown in Spain through the inclusion of parameter uncertainty and variability in the inventories. We fitted statistical distributions for the all the parameter that were relevant for the assessment to take into account their inherent uncertainty and variability. When we found enough data, goodness of fit tests were performed to choose the best distribution for each parameter and, when this was not possible, we adjusted triangular or uniform distributions according to data available and expert judge. To obtain a more complete and realistic LCA, we considered the consequences of straw exportation for the agricultural system, specially the loss of soil organic carbon and the decrease of future fertility. We also took into account all the inputs, transformations and transports needed to generate electricity in a 25 MWe power plant by straw burning. The inventory data for the agricultural, the transport and the transformation phases were collected considering their most common values and ranges of variability for the Spanish case. We used Monte Carlo simulation and sensitivity analysis to obtain global warming potential (GWP) and fossil energy (FOSE) consumption of the system. These results were compared with those of the electricity generated from natural gas in Spanish power plants, as fossil reference energy system. Our results showed that for the majority of the simulations electricity from wheat straw biomass combustion produced less greenhouse gases (GHG) emissions and consumed less fossil energy than electricity from natural gas. However, only 58% of the simulations achieved the sustainability threshold of 60% GHG savings proposed by the European Union (EU). Our analysis showed that agricultural field works and the loss of soil organic carbon due to straw exportation were the most important phases for FOSE consumption and GWP respectively. According to parameters sensitivity analysis, the loss of soil organic carbon was completely dependent on the isohumic coefficient and the soil carbon content factor values. Due to this fact, local and specific estimates of these parameters are relevant tasks to be performed in order to reduce uncertainties and provide a definitive answer to the compliance of the EU sustainability criteria. (C) 2015 Elsevier Ltd. All rights reserved.
  • Authors:
    • Tribouillois,H.
    • Cruz,P.
    • Cohan,J. P.
    • Justes,E.
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 207
  • Year: 2015
  • Summary: Cover crops are used during fallow periods to produce ecosystem services, especially those related to N management such as (i) capturing mineral-N from soil to reduce nitrate leaching, and (ii) improving N availability for the next main crop (green manuring). Bispecific mixtures consisting of legume and non-legume species could simultaneously produce these two services of nitrate saving and green manuring. The magnitude of these services can be estimated from indicators of agroecosystem functions such as crop growth rate, crop N acquisition rate and the C:N ratio of the cover crop. We developed a conceptual model for each indicator which was described using general linear models. A three-step procedure was used: (1) represent the behavior of each species based on a sub-model and calibrate each species in bispecific mixtures; (2) validate the complete-mixture models, corresponding to the sum of the two species sub-models, and the proportion of each species in the whole cover, and (3) validate the generality of sub-models and complete-mixture models to predict the agroecosystem function indicators of species in mixture not used for calibration. The combined use of (i) potential agroecosystem functions measured in sole crop in non-limiting conditions, (ii) difference in leaf functional traits, as indicators of plant strategies and (iii) environmental factors, was efficient in fitting and predicting the level of agroecosystem functions provided by a cover crop species in mixture in actual conditions. The models fitted for bispecific mixtures were efficient to represent the behavior of each species in mixture and to estimate the legume proportion which expressed the species dominance. The models were evaluated as satisfactory for crop growth rate and C:N ratio for their generality in predicting the agroecosystem functions provided in mixtures by other species not used in the model calibration step, which illustrates the relevance and robustness of the approach.
  • Authors:
    • Bosco,S.
    • Volpi,I.
    • o Di Nasso,N. N.
    • Triana,F.
    • Roncucci,N.
    • Tozzini,C.
    • Villani,R.
    • Laville,P.
    • Neri,S.
    • Mattei,F.
    • Virgili,G.
    • Nuvoli,S.
    • Fabbrini,L.
    • Bonari,E.
  • Source: Italian Journal of Agronomy
  • Volume: 10
  • Issue: 3
  • Year: 2015
  • Summary: Agricultural activities are co-responsible for the emission of the most important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Development of methodologies to improve monitoring techniques for N2O are still needful. The LIFE+IPNOA project aims to improve the emissions monitoring of nitrous oxide from agricultural soils and to identify the agricultural practices that can limit N2O production. In order to achieve this objective, both a mobile and a stationary instrument were developed and validated. Several experimental field trials were set up in two different sites investigating the most representative crops of Tuscany (Central Italy), namely durum wheat, maize, sunflower, tomato and faba bean. The field trials were realized in order to test the effect on N2O emissions of key factors: tillage intensity, nitrogen fertiliser rate and irrigation. The field trial on durum wheat was set up in 2013 to test the effect of tillage intensity (minimum and conventional tillage) and nitrogen fertilisation rate (0, 110, 170 kg N ha-1) on soil N2O flux. Monitoring was carried out using the IPNOA mobile prototype. Preliminary results on N2O emissions for the durum wheat growing season showed that mean daily N2O fluxes ranged from –0.13 to 6.43 mg m-2 day-1 and cumulative N2O-N emissions over the period ranged from 827 to 2340 g N2O-N ha-1. Tillage did not affect N2O flux while increasing nitrogen fertilisation rate resulted to significantly increase N2O emissions. The IPNOA mobile prototype performed well during this first year of monitoring, allowing to catch both very low fluxes and peaks on N2O emissions after nitrogen supply, showing a good suitability to the field conditions. © S. Bosco et al., 2015 Licensee PAGEPress, Italy.
  • Authors:
    • Franklin,D.
    • Bender-Özenç,D.
    • Özenç,N.
    • Cabrera,M.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: composts and soil conditioners may be useful soil amendments to provide organic matter as well as nutrients such as n and P, but net n mineralized and P released can vary greatly among materials. consequently, it is important to identify the material characteristics that control these processes. Furthermore, the magnitude of these processes may be affected by particle size. we conducted two laboratory studies at 30°c to: (i) identify variables that can be used to estimate n mineralized and Mehlich-1 P released from 14 composts and soil conditioners; and (ii) evaluate net n mineralized from three size fractions (<1.0 mm, 1.0-2.0, and 2.0-4.0 mm) of five different composts. organic n content and c/n ratio explained 83% of the variability in the amount of net n mineralized or immobilized per unit of material from the 14 composts or conditioners in 214 d. similarly, organic n content and total P content explained 99% of the variability in the amount of Mehlich-1 P released per unit of material. in the study with size fractions, we found that larger size fractions (1-4 mm) mineralized more n (4% of applied n) than the 0-to 1-mm size fraction (0.5%). these results indicate that sieving composts to obtain specific size fractions may affect the rate of n mineralization. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Giguere,A. T.
    • Taylor,A. E.
    • Myrold,D. D.
    • Bottomley,P. J.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: Although ammonia-oxidizing archaea (aoa) and bacteria (aoB) coexist in most non-acidic agricultural soils, the factors that influence their relative contributions to soil nitrification activity remain unclear. a 2-to 4-d whole soil microcosm assay was developed, utilizing the aliphatic c8 alkyne 1-octyne to inactivate aoB-driven nitrification activity without impacting aoa nitrification activity. responses of aoa-and aoB-supported net nitrifi-cation activities (accumulation of no2-+ no3-) to different concentrations of extractable nH4 + were examined in four diverse, paired cropped and non-cropped Oregon soils sampled in summer and winter. Maximum aoasupported net nitrification rates were significantly higher in non-cropped (3.7 mg n kg-1 soil d-1) than in cropped soils (0.9 mg n kg-1 soil d-1) and in summer (3.1 mg n kg-1 soil d-1) compared with winter soils (1.6 mg n kg-1 soil d-1). the nH4 + concentration required to significantly stimulate aoB nitrification activity was significantly higher in cropped soils (67 mg n kg-1 soil) than in non-cropped soils (12 mg n kg-1 soil). Maximum aoB activity was significantly higher in cropped (8.6 mg n kg-1 soil d-1) than in non-cropped soils (2.9 mg n kg-1 soil d-1) and in summer (7.8 mg n kg-1 soil d-1) compared with winter soils (3.8 mg n kg-1 soil d-1). this study revealed that aoa-and aoB-supported nitrification rates in cropped and non-cropped soils respond differently to season and nH4 + concentration and raises the possibility that aoa and aoB nitrification activities might be differentially managed to improve n use efficiency. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Guo,Miao
    • Li,Changsheng
    • Facciotto,Gianni
    • Bergante,Sara
    • Bhatia,Rakesh
    • Comolli,Roberto
    • Ferre,Chiara
    • Murphy,Richard
  • Source: Biotechnology for Biofuels
  • Volume: 8
  • Year: 2015
  • Summary: Background: Environmental issues, e.g. climate change, fossil resource depletion have triggered ambitious national/regional policies to develop biofuel and bioenergy roles within the overall energy portfolio to achieve decarbonising the global economy and increase energy security. With the 10 % binding target for the transport sector, the Renewable Energy Directive confirms the EU's commitment to renewable transport fuels especially advanced biofuels. Imola is an elite poplar clone crossed from Populus deltoides Bartr. and Populus nigra L. by Research Units for Intensive Wood Production, Agriculture Research Council in Italy. This study examines its suitability for plantation cultivation under short or very short rotation coppice regimes as a potential lignocellulosic feedstock for the production of ethanol as a transport biofuel. A life cycle assessment (LCA) approach was used to model the cradle-to-gate environmental profile of Imola-derived biofuel benchmarked against conventional fossil gasoline. Specific attention was given to analysing the agroecosystem fluxes of carbon and nitrogen occurring in the cultivation of the Imola biomass in the biofuel life cycle using a process-oriented biogeochemistry model (DeNitrification-DeComposition) specifically modified for application to 2G perennial bioenergy crops and carbon and nitrogen cycling. Results: Our results demonstrate that carbon and nitrogen cycling in perennial crop-soil ecosystems such as this example can be expected to have significant effects on the overall environmental profiles of 2G biofuels. In particular, soil carbon accumulation in perennial biomass plantations is likely to be a significant component in the overall greenhouse gas balance of future biofuel and other biorefinery products and warrants ongoing research and data collection for LCA models. We conclude that bioethanol produced from Imola represents a promising alternative transport fuel offering some savings ranging from 35 to 100 % over petrol in global warming potential, ozone depletion and photochemical oxidation impact categories. Conclusions: Via comparative analyses for Imola-derived bioethanol across potential supply chains, we highlight priority issues for potential improvement in 2G biofuel profiling. Advanced clones of poplar such as Imola for 2G biofuel production in Italy as modelled here show potential to deliver an environmentally sustainable lignocellulosic biorefinery industry and accelerate advanced biofuel penetration in the transport sector.
  • Authors:
    • Ho,A.
    • Reim,A.
    • Kim SangYoon
    • Meima-Franke,M.
    • Termorshuizen,A.
    • Boer,W. de
    • Putten,W. H. van der
    • Bodelier,P. L. E.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 10
  • Year: 2015
  • Summary: Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO 2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may compensate for the loss of the methane sink function following land-use change.
  • Authors:
    • Nishina,Kazuya
    • Sudo,Shigeto
    • Yagi,Kazuyuki
    • Sano,Tomohito
    • Takata,Yusuke
    • Obara,Hiroshi
    • Eguchi,Sadao
    • Oura,Noriko
    • Yano,Shinji
    • Ohkoshi,Satoru
    • Fujita,Yutaka
    • Shiratori,Yutaka
    • Tsuji,Masaki
    • Hasukawa,Hiroyuki
    • Suzue,Yasufumi
    • Yamada,Yasunao
    • Mizukami,Hiroyuki
    • Uezono,Ichiro
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 103
  • Issue: 1
  • Year: 2015
  • Summary: The use of N fertilizers for agricultural production acts as a sources of atmospheric . Fertilizer induced emission considerably varies in accordance with environmental factors. We conducted a flux measurement campaign across 10 different experimental sites with various soil types throughout Japan and investigated the fertilizer induced emission factors (FIEFs) of synthetic fertilizers (mainly urea) in multiple growing periods at each experimental site. FIEFs considerably varied among the 10 sites, and measurement periods ranged from 0.00 to 7.13 % in 40 total observations. Soil profile information divided the experimental sites into two major groups through cluster analysis, which are volcanic or non-volcanic soils. According to this classification, FIEFs were clearly differentiated into high and low FIEF groups (mean values: 2.67 and 0.59 %, respectively). Regression trees selected total soil carbon, the depth to the Fe mottling horizon, and mean air temperature as the key parameters to determine the strength of FIEFs out of 10 explanatory variables (e.g., N fertilizer application rates, fertilizer application times, clay content, total precipitation during measurement periods, pH, total soil carbon, and total soil nitrogen). The existence of shallow Fe mottling layer (up to 42.5 cm) induced high FIEFs in this model, suggesting that upward emissions derived from the intermediate Fe mottling layers presumably contributed high emissions in such soils. Our results suggest that the soil profile information associated with the water regime is an important index for synthetic fertilizer induced emissions.
  • Authors:
    • Visser,F.
    • Dargusch,P.
    • Smith,C.
    • Grace,P. R.
  • Source: Journal of Cleaner Production
  • Volume: 103
  • Year: 2015
  • Summary: The various initiatives in the market place to quantify the sustainability levels of products are putting pressure on farmers to demonstrate a reduction in the environmental impacts of their crop management practices, and in particular with the lowering of the carbon footprints of their crops. At present there is no internationally accredited common method or carbon footprint model which generates site specific and LCA aligned emission estimates. The application of the Crop Carbon Progress Calculator (CCAP) is demonstrated for an irrigated cotton 'farm to ship' case study in Australia where we determine that the progress made in the 2011 crop against a 2002 crop base year amounts to 44% reduction in GHG emission levels. We estimate that for this particular case study the total carbon footprint of producing a bale of cotton up to ship's side or point of export is 323 kg CO 2e. This includes 182 kg CO 2e from the farm production phase, 73.1 kg CO 2e from the gin to port supply chain, and 68.1 kg CO 2e that results from emission from the stock piled gin trash at the gins. It appears that a feasible option to avoid these trash emissions is to incorporate the waste at farm level. Our analysis shows that this could generate an emissions credit of 48.8 kg CO 2e per bale at farm level, which will amount to a 27% reduction in the farm emissions footprint and a 15% reduction in the whole farm to ship carbon footprint. Due to a number of site specific environmental and crop management factors, there can be significant variances in crop carbon footprint outcomes.
  • Authors:
    • Borghi, E.
    • Nascente, A. S.
    • Crusciol, C. A. C.
    • Soratto, R. P.
    • Martins, P. O.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: In tropical regions with dry winters, low plant biomass accumulation during the period between spring-summer crop cultivations can negatively impact soil resources and make the no-till (NT) system unsustainable. Incorporating palisadegrass [ Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster] [syn. Brachiaria brizantha (Hochst. Ex A. Rich) Stapf] in traditional grain production areas could improve soil quality for subsequent crops and lead to positive effects on grain yield. The objective of this study was to evaluate the effects of growing palisadegrass on soil fertility, plant nutrition, and grain yield of subsequent cash crops in a tropical region. The experiment was performed in southeastern Brazil in plots that were grown for two consecutive growing seasons (2002-2003 and 2003-2004) with either monocropped corn ( Zea mays L.) or corn intercropped with palisadegrass. An initial evaluation of soil fertility was performed in November 2004 when the land was either fallow (following monocropped corn) or covered by palisadegrass (intercropped areas). After the preceding treatments, the following crops were cultivated: soybean [ Glycine max (L.) Merr.] during the 2004-2005 and 2005-2006 spring-summer, white oat ( Avena sativa L.) during the 2005 and 2006 fall-winter, and corn during the 2006-2007 spring-summer. Intercropping palisadegrass with corn increased the soil fertility compared to monocropped corn. Soybean, white oat, and corn all had higher leaf macronutrient concentrations and grain yields in previously intercropped areas than in monocropped areas. Therefore, the periodic, short-term incorporation of a perennial forage grass, such as palisadegrass, as a cover crop is recommended to increase grain production and to improve the soil fertility of grain-production areas.