• Authors:
    • Messiga, A. J.
    • Burton, D. L.
    • Hammermeister, A.
    • Lynch, D. H.
    • Sharifi, M.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 100
  • Issue: 2
  • Year: 2014
  • Summary: The effects of green manure, crop sequence and off-farm composts on selected soil quality parameters were assessed in a three-year organic potato (Solanum tuberosum L.) rotation in Eastern Canada. Three crop sequences varying in preceding green manure [red clover (RCl) + RCl, and beans/buckwheat or carrots + oats/peas/vetch mixture (OPV)] as main plots and four fertility treatments applied in the potato phase only [control; inorganic fertilizer; municipal solid waste compost (MSW); composted paper mill biosolid (PMB)] as subplots were compared. In 2008 and 2010, changes in selected soil quality parameters (0-15 cm) were assessed prior to planting of potatoes and at potato tuber initiation stage. Potentially mineralizable nitrogen (N) and the acid phosphatase enzyme activity average values across years were greater following RCl (1.51 abs and 622 kg ha(-1)) compared with OPV (1.32 abs and 414 kg ha(-1)) at potato planting. Soil NO3-N average value was greater following RCl compared with OPV (63 vs. 52 kg ha(-1)) at tuber initiation. For the other measured parameters, OPV and RCl were similar. The soil organic carbon (C) and particulate organic matter-C were greater under PMB and MSW (31.1 and 7.57 kg ha(-1)) compared with fertilizer treatment (27.9 and 6.05 kg ha(-1)). The microbial biomass C and microbial biomass quotient were greater under MSW (216 kg ha(-1) and 0.73 %) than PMB and fertilizer (147 kg ha(-1) and 0.50 %) across crop rotations. Annual legume green manures and off-farm composts can be used to satisfy potato N requirement and maintains soil quality in organic potato rotations.
  • Authors:
    • Thibeault, J. M.
    • Seth, A.
  • Source: CLIMATIC CHANGE
  • Volume: 127
  • Issue: 2
  • Year: 2014
  • Summary: Climate extremes indices are evaluated for the northeast United States and adjacent Canada (Northeast) using gridded observations and twenty-three CMIP5 coupled models. Previous results have demonstrated observed increases in warm and wet extremes and decreases in cold extremes, consistent with changes expected in a warming world. Here, a significant shift is found in the distribution of observed total annual precipitation over 1981-2010. In addition, significant positive trends are seen in all observed wet precipitation indices over 1951-2010. For the Northeast region, CMIP5 models project significant shifts in the distributions of most temperature and precipitation indices by 2041-2070. By the late century, the coldest (driest) future extremes are projected to be warmer (wetter) than the warmest (wettest) extremes at present. The multimodel interquartile range compares well with observations, providing a measure of confidence in the projections in this region. Spatial analysis suggests that the largest increases in heavy precipitation extremes are projected for northern, coastal, and mountainous areas. Results suggest that the projected increase in total annual precipitation is strongly influenced by increases in winter wet extremes. The largest decreases in cold extremes are projected for northern and interior portions of the Northeast, while the largest increases in summer warm extremes are projected for densely populated southern, central, and coastal areas. This study provides a regional analysis and verification of the latest generation of CMIP global models specifically for the Northeast, useful to stakeholders focused on understanding and adapting to climate change and its impacts in the region.
  • Authors:
    • Yemshanov, D.
    • MacGregor, B.
    • Smith, S.
    • Huffman, T.
    • McConkey, B.
    • Liu, T. T.
    • Kulshreshtha, S.
  • Source: APPLIED ENERGY
  • Volume: 130
  • Year: 2014
  • Summary: Agriculture has the potential to supply considerable amounts of biomass for renewable energy production from dedicated energy crops as well as from crop residues of existing production. Bioenergy production can contribute to the reduction of greenhouse gas (GHG) emissions by using ethanol and biodiesel to displace petroleum-based fuels and through direct burning of biomass to offset coal use for generating electricity. We used the Canadian Economic and Emissions Model for Agriculture to estimate the potential for renewable energy production from biomass, the impacts on agricultural production, land use change and greenhouse gas emissions. We explored two scenarios: the first considers a combination of market incentives and policy mandates (crude oil price of $120 bbl -1; carbon offset price of $50 Mg -1 CO 2 equivalent and policy targets of a substitution of 20% of gasoline by biomass-based ethanol; 8% of petroleum diesel by biodiesel and 20% of coal-based electricity by direct biomass combustion), and a second scenario considers only carbon offset market incentives priced at $50 Mg -1 CO 2 equivalent. The results show that under the combination of market incentives and policy mandates scenario, the production of biomass-based ethanol and electricity increases considerably and could potentially cause substantial changes in land use practices. Overall, agriculture has considerable potential to generate biomass for energy and a significant potential for GHG emission reductions, however the proportional mix of policy and market incentives would have a large impact on the type of bioenergy produced.
  • Authors:
    • Onder, S.
    • Sivritepe, N.
    • Kamiloglu, O.
    • Daghan, H.
  • Source: Agronomy Journal
  • Volume: 23
  • Issue: 9
  • Year: 2014
  • Summary: The objective of the present study is to investigate the physiological, morphological and structural changes induced by water deficit on four different table grape cultivars that are commonly cultivated in the Mediterranean region. One-year-old vine ( Vitis vinifera L.), cultivars 'Crimson Seedless', 'Superior Seedless', 'Razaki' and 'Horoz Karasi' grafted onto 1103 P rootstock were grown in a greenhouse in a soil/farmyard manure/sand/turf mixture (2:1:1:0.5) in pots; and subjected to water stress for 40 days. A 60% limitation of the available water caused total leaf area and dry weight decrease as well as negative impact on growth in all cultivars. As a result of this application, a distinctive decrease in root growth was observed in the Crimson Seedless, Superior Seedless and Razaki cultivars, in comparison with the control. While there was no significant change in grade of leaf thickness, leaf tissue density, or leaf succulence during water stress application, increases in leaf K, Fe, Cu, and Zn contents, chlorophyll content, and leaf electrolyte leakage were observed. Significant differences were seen among the grape cultivars in terms of adaptation to aridity conditions. Generally, the most sensitive grape cultivar in terms of tolerance to water stress was Superior Seedless, whereas the cultivar that can optimally adapt to conditions of higher aridity was Horoz Karasi.
  • Authors:
    • Amichev,Beyhan Y.
    • Hangs,Ryan D.
    • Konecsni,Sheala M.
    • Stadnyk,Christine N.
    • Volk,Timothy A.
    • Belanger,Nicolas
    • Vujanovic,Vladimir
    • Schoenau,Jeff J.
    • Moukoumi,Judicael
    • Van Rees,Ken C. J.
  • Source: Soil Science Society of America Journal
  • Volume: 78
  • Issue: 1
  • Year: 2014
  • Summary: Willow (Salix spp.) short-rotation coppice (SRC) systems are becoming an attractive practice because they are a sustainable system fulfilling multiple ecological objectives with significant environmental benefits. A sustainable supply of bioenergy feedstock can be produced by willow on marginal land using well-adapted or tolerant cultivars. Across Canada and the northern United States, there are millions of hectares of available degraded land that have the potential for willow SRC biomass production, with a C sequestration potential capable of offsetting appreciable amounts of anthropogenic greenhouse gas emissions. A fundamental question concerning sustainable SRC willow yields was whether long-term soil productivity is maintained within a multi-rotation SRC system, given the rapid growth rate and associated nutrient exports offsite when harvesting the willow biomass after repeated short rotations. Based on early results from the first willow SRC rotation, it was found that willow systems have relatively low nutrient demands, with minimal nutrient outputs other than in the harvested biomass. Our overall aim was to summarize the literature and present findings and data from ongoing research trials across Canada and the northern United States examining willow SRC system establishment and viability. The research areas of interest are the crop production of willow SRC systems, above-and belowground biomass dynamics and the C budget, comprehensive soil-willow system nutrient budgets, and soil nutrient amendments (via fertilization) in willow SRC systems. Areas of existing research gaps were also identified for the Canadian context.
  • 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:
    • Halvorson, A. D.
    • Jantalia, C. P.
    • Follett, R. F.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 3
  • Year: 2013
  • Summary: Conventional tillage (CT) with high N rates and irrigation is used more frequently than no-till (NT) for growing continuous corn (Zea mays L.) in the central Great Plains of the United States. The objective of this study was to evaluate soil organic C (SOC) stocks throughout the soil profile as well as the potential for maintaining or sequestering SOC within the soil profile (0- 120 cm) under irrigated, continuous corn as affected by NT and CT and three N rates. Isotopic δ13C techniques provided information about the fate of C added to soil by corn (C4-C) and of residual C3-C from cool-season plants grown before this study. Relative contributions of C4-C and C3-C to SOC stocks after 8 yr were determined. Retention of C4-C from corn was measured under NT and CT. Nitrogen fertilization slowed losses of C3-C and improved retention of C 4-C. No-till was superior to CT in maintaining SOC. Deep soil sampling to 120 cm and the use of stable C isotope techniques allowed evaluation of changes in SOC stocks during the 8-yr period. Change in SOC under NT vs. CT resulted from greater loss of C3-C stocks under CT throughout the soil profile. Irrigated corn has a low potential to sequester SOC in the central Great Plains, especially under CT. The results of this study indicate that stability of the soil organic matter and its perceived "recalcitrance" is altered by environmental and biological controls. © Soil Science Society of America.
  • 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.
  • Authors:
    • Smith, P.
    • Williams, M.
    • Forristal, D.
    • Lanigan, G.
    • Osborne, B.
    • Abdalla, M.
    • Jones, M. B.
  • Source: Soil Use and Management
  • Volume: 29
  • Issue: 2
  • Year: 2013
  • Summary: Conservation tillage (CT) is an umbrella term encompassing many types of tillage and residue management systems that aim to achieve sustainable and profitable agriculture. Through a global review of CT research, the objective of this paper was to investigate the impacts of CT on greenhouse gas (GHG) emissions. Based on the analysis presented, CT should be developed within the context of specific climates and soils. A number of potential disadvantages in adopting CT practices were identified, relating mainly to enhanced nitrous oxide emissions, together with a number of advantages that would justify its wider adoption. Almost all studies examined showed that the adoption of CT practices reduced carbon dioxide emissions, while also contributing to increases in soil organic carbon and improvements in soil structure.
  • Authors:
    • Schoenau, J. J.
    • Alotaibi, K. D.
  • Source: Biology and Fertility of Soils
  • Volume: 49
  • Issue: 2
  • Year: 2013
  • Summary: Ethanol production results in distiller grain, and biodiesel produces glycerol as by-product. However, there is limited information on effects of their addition on evolution of N2O and CO2 from soils, yet it is important to enable our understanding of impacts of biofuel production on greenhouse gas budgets. The objective of this study was to evaluate the direct effects of adding wet distillers grain (WDG), thin stillage (TS), and glycerol at three rates on greenhouse gas emissions (N2O and CO2) and nutrient supply rates in a cultivated soil from the Canadian prairies. The WDG and TS application rates were: 100, 200, or 400 kg N ha(-1), whereas glycerol was applied at: 40, 400, or 4,000 kg C ha(-1) applied alone (G -aEuro parts per thousand N) or in a combination with 300 kg N ha(-1) (G + N). In addition, conventional amendments of urea (UR) and dehydrated alfalfa (DA) were added at the same rates of total N as the by-products for comparative purposes. The production of N2O and CO2 was measured over an incubation period of 10 days in incubation chambers and Plant Root Simulator (TM) resin membrane probes were used to measure nutrient (NH (4) (+) -N, NO (3) (-) -N, and PO (4) (-3) -P) supply rates in the soil during incubation. Per unit of N added, urea tended to result in the greatest N2O production, followed by wet distillers grain and thin stillage, with glycerol and dehydrated alfalfa resulting in the lowest N2O production. Cumulative N2O production increased with increasing the rate of N-containing amendments and was the highest at the high rate of UR treatment. Addition of urea with glycerol contributed to a higher rate of N2O emission, especially at the low rate of glycerol. The DA and WDG resulted in the greatest evolution of CO2 from the soil, with the thin stillage resulting in less CO2 evolved per unit of N added. Addition of N fertilizer along with glycerol enhanced microbial activity and decomposition. The amendments had significant impacts on release of available nutrient, with the UR treatments providing the highest NO (3) (-) -N supply rate. The TS treatments supplied the highest rate of NH (4) (+) -N, followed by WDG compared to the other amendments. The WDG treatments were able to provide the greatest supply of PO (4) (-3) -P supply in comparison to the other amendments. Microbial N immobilization was associated with glycerol treatments applied alone. This study showed that the investigated biofuel by-products can be suitable soil amendments as a result of their ability to supply nutrients and N2O emissions that did not exceed that of the conventional urea fertilizer.