• Authors:
    • Prade,T.
    • Svensson,S. E.
    • Bjornsson,L.
  • Source: Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector
  • Year: 2014
  • Summary: Changes of soil organic carbon (SOC) content can have a substantial effect on greenhouse gas emissions, but are rarely included in crop production LCAs. SOC content strongly influences soil fertility and therefore crop yields, but is declining in many European soils. The present study investigated if integration of 1-2 years of grass-clover crops in a cereal-dominated crop rotation can increase the SOC pool and how this would impact food production. Results show that when grass-clover crops are integrated, the potential SOC content at steady state will be 41 to 52% higher than in the conventional cereal-dominated crop rotation. The net increase of wheat yields based on SOC improvements indicate that for a crop rotation with one year of grass-clover crops, the initial loss of food production can be counterbalanced due to the impact on fertility of the SOC increase.
  • Authors:
    • Zwickel, T.
    • Van Vuuren, D. P.
    • Winkler, H.
    • Riahi, K.
    • O'Neill, B. C.
    • Mathur, R.
    • Kriegler, E.
    • Edmonds, J.
    • Carter, T. R.
    • Arnell, N. W.
    • Kram, T.
    • Hallegatte, S.
    • Ebi, K. L.
  • Source: Research Article
  • Volume: 122
  • Issue: 3
  • Year: 2014
  • Summary: The scientific community is developing new global, regional, and sectoral scenarios to facilitate interdisciplinary research and assessment to explore the range of possible future climates and related physical changes that could pose risks to human and natural systems; how these changes could interact with social, economic, and environmental development pathways; the degree to which mitigation and adaptation policies can avoid and reduce risks; the costs and benefits of various policy mixes; and the relationship of future climate change adaptation and mitigation policy responses with sustainable development. This paper provides the background to and process of developing the conceptual framework for these scenarios, as described in the three subsequent papers in this Special Issue (Van Vuuren et al., 2013; O'Neill et al., 2013; Kriegler et al., Submitted for publication in this special issue). The paper also discusses research needs to further develop, apply, and revise this framework in an iterative and open-ended process. A key goal of the framework design and its future development is to facilitate the collaboration of climate change researchers from a broad range of perspectives and disciplines to develop policy- and decision-relevant scenarios and explore the challenges and opportunities human and natural systems could face with additional climate change.
  • Authors:
    • Vuuren, D. P.
    • Tavoni, M.
    • Rose, S. K.
    • Richels, R.
    • Riahi, K.
    • Luderer, G.
    • Fawcett, A.
    • Edmonds, J.
    • Clarke, L.
    • Krey, V.
    • Blanford, G. J.
    • Weyant, J. P.
    • Kriegler, E.
  • Source: Web Of Knowledge
  • Volume: 123
  • Issue: 3-4
  • Year: 2014
  • Summary: This article presents the synthesis of results from the Stanford Energy Modeling Forum Study 27, an inter-comparison of 18 energy-economy and integrated assessment models. The study investigated the importance of individual mitigation options such as energy intensity improvements, carbon capture and storage (CCS), nuclear power, solar and wind power and bioenergy for climate mitigation. Limiting the atmospheric greenhouse gas concentration to 450 or 550 ppm CO2 equivalent by 2100 would require a decarbonization of the global energy system in the 21(st) century. Robust characteristics of the energy transformation are increased energy intensity improvements and the electrification of energy end use coupled with a fast decarbonization of the electricity sector. Non-electric energy end use is hardest to decarbonize, particularly in the transport sector. Technology is a key element of climate mitigation. Versatile technologies such as CCS and bioenergy are found to be most important, due in part to their combined ability to produce negative emissions. The importance of individual low-carbon electricity technologies is more limited due to the many alternatives in the sector. The scale of the energy transformation is larger for the 450 ppm than for the 550 ppm CO(2)e target. As a result, the achievability and the costs of the 450 ppm target are more sensitive to variations in technology availability.
  • Authors:
    • Zurek, A.
    • Pecio, A.
    • Niedzwiecki, J.
    • Debaene, G.
  • Source: Research Article
  • Volume: 214
  • Issue: 214–215
  • Year: 2014
  • Summary: Precision agriculture (PA) is a management method that measures and manages within-field variability. Previously, PA has required expansive and time consuming measurement of soil physical and chemical properties. In this paper we use a new and more rapid method of data collection based on Visible and Near-Infrared Spectroscopy (VIS-NIRS) in the 400-2200 nm spectral range to predict soil organic carbon (SOC), plant available [Mg, P, K], pH and texture at the farm scale. The experimental work was done at the experimental Station at Baborowko (52.583778 degrees N, 16.647353 degrees E) in Poland. The focus of the paper was to look at the effect of the number of samples on the calibration. Different calibration schemes using PLS regression with calibration datasets of different sizes were applied. The best predictions were obtained using K-means clustering for calibration sample selection. Using this scheme and 79 calibration samples, satisfactory results were obtained predicting SOC (r(2) = 0.63; RMSEP = 0.13%) and soil texture (e.g. clay, r(2) = 0.71; RMSEP = 0.36%). The use of the entire dataset did not improve significantly the prediction ability (r(2) = 0.72; RMSEP = 0.12% for SOC and r(2) = 0.73; RMSEP = 032% for clay). Reasonable results were obtained for available Mg content (r(2) = 0.53; RMSEP = 1.54 mg.100 g(-1)) and pH (r(2) -= 0.52; RMSEP = 034 pH unit). Available [P, K] gave unsatisfactory results (r(2) < 0.5 for both; RMSEP 6.27 and 331 mg.100 g(-1) respectively). The maps (SOC and pH) generated with the K-means clustering scheme were compared with those obtained with reference data. The results show that the VIS-NIRS method is suitable to adequately predict SOC and texture using 1.5 samples per ha (79 samples). The method can also be useful as a rough screening for pH and available Mg thereby significantly reducing the cost of mapping. (C) 2013 Elsevier B.V. All rights reserved.
  • Authors:
    • Merz, K.
    • Stolnikova, E.
    • Wiesenberg, G. L. B.
    • Hafner, S.
    • Kuzyakov, Y.
  • Source: Regular Article
  • Volume: 380
  • Issue: 1-2
  • Year: 2014
  • Summary: This study analyzed the extent to which root exudates diffuse from the root surface towards the soil depending on topsoil and subsoil properties and the effect of arbuscular mycorrhizal fungal hyphae on root-derived C distribution in the rhizosphere. Alfalfa was grown in three-compartment pots. Nylon gauze prevented either roots alone or roots and arbuscular mycorrhizal fungal hyphae from penetrating into the rhizosphere compartments. (CO2)-C-14 pulse labeling enabled the measurement of C-14-labeled exudates in dissolved (DOC) and total organic carbon (TOC) in the rhizosphere, distributed either by diffusion alone or by diffusion, root hair and hyphal transport. Root exudation and microbial decomposition of exudates was higher in the rhizosphere with topsoil compared to subsoil properties. Exudates extended over 28 mm (DOC) and 20 mm (TOC). Different soil properties and mycorrhization, likely caused by the low arbuscular mycorrhizal colonization of roots (13 +/- 4 % (topsoil properties) and 18 +/- 5 % (subsoil properties)), had no effect. Higher microbial decomposition compensated for higher root exudation into the rhizosphere with topsoil properties, which resulted in equal exudate extent when compared to the rhizosphere with subsoil properties. Higher C-14 activity used for labeling compared with previous studies enabled the detection of low exudate concentrations at longer distances from the root surface.
  • Authors:
    • Long, S. P.
    • Ort, D. R.
  • Source: Article
  • Volume: 344
  • Issue: 6183
  • Year: 2014
  • Summary: In total global production, corn (maize, <I>Zea mays</I> L.) is the most important food and feed crop. Of the 967 million metric tons produced in 2013, 36.5% were produced in the United States, mostly in the Midwest Corn Belt. The United States is by far the world's largest corn exporter, accounting for 50% of corn exports globally (<I>1</I>, <I>2</I>). Until recently, breeding and management have allowed farmers to increase the number of plants per acre without loss of yield per plant. On page 516 of this issue, Lobell <I>et al.</I> (<I>3</I>) use a detailed data set for farms across the Corn Belt, to show that increasing yields have been accompanied by rising drought sensitivity, with important implications for future crop yields.
  • Authors:
    • Siegfried, W.
    • Rohr, C.
    • Riemann, D.
    • Retso, D.
    • Pribyl, K.
    • Nordl, O.
    • Litzenburger, L.
    • Limanowka, D.
    • Labbe, T.
    • Kotyza, O.
    • Kiss, A.
    • Himmelsbach, I.
    • Glaser, R.
    • Dobrovolny, P.
    • Contino, A.
    • Camenisch, C.
    • Burmeister, K.
    • Brazdil, R.
    • Bieber, U.
    • Barriendos, M.
    • Alcoforado, M.
    • Luterbacher, J.
    • Gruenewald, U.
    • Herget, J.
    • Seneviratne, S.
    • Wagner, S.
    • Zorita, E.
    • Werner, J.
    • Pfister, C.
    • Wetter, O.
    • Soderberg, J.
    • Spring, J.
  • Source: Climatic Change
  • Volume: 125
  • Issue: 3-4
  • Year: 2014
  • Summary: The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring-summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km(2), we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.
  • Authors:
    • Odlare, M.
    • Abubaker, J.
    • Pell, M.
  • Source: Journal of Environmental Quality
  • Volume: 42
  • Issue: 4
  • Year: 2013
  • Summary: The amount of residues generated from biogas production has increased dramatically due to the worldwide interest in renewable energy. A common way to handle the residues is to use them as fertilizers in crop production. Application of biogas residues to agricultural soils may be accompanied with environmental risks, such as increased N 2O emission. In 24-d laboratory experiments, N 2O dynamics and total production were studied in arable soils (sandy, clay, and organic) amended with one of two types of anaerobically digested biogas residues (BR-A and BR-B) generated from urban and agricultural waste and nondigested cattle slurry (CS) applied at rates corresponding to 70 kg NH 4+-N ha -1. Total N 2O-N losses from the sandy soil were higher after amendment with BR-B (0.32 g N 2O-N m -2) than BR-A or CS (0.02 and 0.18 g N 2O-N m -2, respectively). In the clay soil, N 2O-N losses were very low for CS (0.02 g N 2O-N m -2) but higher for BR-A and BR-B (0.25 and 0.15 g N 2O-N m -2, respectively). In the organic soil, CS gave higher total N 2O-N losses (0.31 g N 2O-N m -2) than BR-A or BR-B (0.09 and 0.08 g N 2O-N m -2, respectively). Emission peaks differed considerably between soils, occurring on Day 1 in the organic soil and on Days 11 to 15 in the sand, whereas in the clay the peak varied markedly (Days 1, 6, and 13) depending on residue type. In all treatments, NH 4+ concentration decreased with time, and NO 3- concentration increased. Potential ammonium oxidation and potential denitrification activity increased significantly in the amended sandy soil but not in the organic soil and only in the clay amended with CS. The results showed that fertilization with BR can increase N 2O emissions and that the size is dependent on the total N and organic C content of the slurry and on soil type. In conclusion, the two types of BR and the CS are not interchangeable regarding their effects on N 2O production in different soils, and, hence, matching fertilizer type to soil type could reduce N 2O emissions. For instance, it could be advisable to avoid fertilization of organic soils with CS containing high amounts or organic C and instead use BR. In clay soil, however, the risk of N 2O emissions could be lowered by choosing a CS.
  • Authors:
    • Kennedy, A. C.
    • Bary, A. I.
    • Cogger, C. G.
    • Fortuna, A. M.
  • Source: Journal of Environmental Quality
  • Volume: 42
  • Issue: 6
  • Year: 2013
  • Summary: Biosolids have the potential to improve degraded soils in grain-fallow rotations. Our objectives were to determine if repeated biosolids applications in wheat ( Triticum aestivum L.) - fallow could supply adequate but not excessive N for grain production and increase soil C without creating a high risk of P loss. A replicated on-farm experiment was established in 1994 in central Washington, comparing anaerobically digested biosolids with anhydrous NH 3 and a zero-N control. Biosolids were applied at 5, 7, and 9 Mg ha -1 every fourth year through 2010 and incorporated 10 cm deep, while anhydrous NH 3 plots received 56 kg ha -1 N every second year. Grain yield and protein were determined. Soil chemical, biological, and bulk density analyses were made in 2012. Medium and high biosolids rates significantly increased grain yield (3.63 vs. 3.13 Mg ha -1) and protein (103 vs. 85 g kg -1) compared with anhydrous NH 3 averaged across all crops. The medium biosolids rate had significantly lower bulk density (1.05 vs. 1.22 g kg -1) and greater total C (0-10-cm depth) (16.9 vs. 9.4 g kg -1), mineralizable N (156 vs. 52 mg kg -1), and extractable P (114 vs. 16 mg kg -1) than anhydrous NH 3. The P index site vulnerability increased from low for anhydrous NH 3 to medium for the biosolids treatments. Soil NO 3-N was nearly always <10 mg N kg -1 soil (0-30-cm depth). Medium and high biosolids rates significantly increased bacteria/fungi ratios, Gram-negative bacteria, and anaerobic bacteria markers compared with anhydrous NH 3. Biosolids can be an agronomically and environmentally sound management practice in wheat-fallow systems.
  • Authors:
    • Nyachiro, J. M.
    • Salmon, D. F.
    • Beres, B. L.
    • Collier, G. R. S.
    • Bork, E. W.
    • Spaner, D. M.
  • Source: Agronomy Journal
  • Volume: 105
  • Issue: 2
  • Year: 2013
  • Summary: Triticale (* Triticosecale Wittmack) is a minor cereal crop in Alberta which has recently garnered interest as a biofuel feedstock. Basic agronomic information is lacking for triticale cultivars released since 1990. Field experiments were initiated in 2010 and conducted for 2 yr at four sites in central and southern Alberta to compare the impact of cultivar selection, seeding date, and seeding rate on grain yield, grain quality, and other agronomic traits. Six triticale cultivars released between 1996 and 2011, and one Soft White Spring wheat cultivar ( Triticum aestivum L.) were evaluated over two seeding dates; one before and one after 15% of the total seasonal growing degree days (GDD; base=0°C) had elapsed. The cultivars were evaluated at seeding rates of 250, 375, and 500 seeds m -2. Older triticale cultivars had higher grain yields but lower grain quality than cultivars released after 2000. The triticale cultivars produced more grain than Soft White Spring wheat in five of seven environments; however, Soft White Spring wheat exhibited better grain quality than the triticales. Yield generally increased linearly with seeding rate but the highest return on investment was observed at 375 seeds m -2. Provided there was not an early frost, triticale seeded after 15% of the seasonal GDD had elapsed could produce grain yield similar to the earlier-seeded triticale. A sustainable management system for triticale includes modern cultivars, a seeding date that can accumulate 1750 GDD's before frost, and a sowing density of at least 375 seeds m -2.