• Authors:
    • Dale, B. E.
    • Kim, S.
  • Source: Biomass and Bioenergy
  • Volume: 26
  • Issue: 4
  • Year: 2004
  • Summary: The global annual potential bioethanol production from the major crops, corn, barley, oat, rice, wheat, sorghum, and sugar cane, is estimated. To avoid conflicts between human food use and industrial use of crops, only the wasted crop, which is defined as crop lost in distribution, is considered as feedstock. Lignocellulosic biomass such as crop residues and sugar cane bagasse are included in feedstock for producing bioethanol as well. There are about 73:9 Tg of dry wasted crops in the world that could potentially produce 49:1 GL year-1 of bioethanol. About 1:5 Pg year-1 of dry lignocellulosic biomass from these seven crops is also available for conversion to bioethanol. Lignocellulosic biomass could produce up to 442 GL year-1 of bioethanol. Thus, the total potential bioethanol production from crop residues and wasted crops is 491 GL year-1, about 16 times higher than the current world ethanol production. The potential bioethanol production could replace 353 GL of gasoline (32% of the global gasoline consumption) when bioethanol is used in E85 fuel for a midsize passenger vehicle. Furthermore, lignin-rich fermentation residue, which is the coproduct of bioethanol made from crop residues and sugar cane bagasse, can potentially generate both 458 TWh of electricity (about 3.6% of world electricity production) and 2:6EJ of steam. Asia is the largest potential producer of bioethanol from crop residues and wasted crops, and could produce up to 291 GL year -1 of bioethanol. Rice straw, wheat straw, and corn stover are the most favorable bioethanol feedstocks in Asia. The next highest potential region is Europe (69:2 GL ofbioethanol), in which most bioethanol comes from wheat straw. Corn stover is the main feedstock in North America, from which about 38:4 GL year -1 of bioethanol can potentially be produced. Globally rice straw can produce 205 GL of bioethanol, which is the largest amount from single biomass feedstock. The next highest potential feedstock is wheat straw, which can produce 104 GL of bioethanol. This paper is intended to give some perspective on the size ofthe bioethanol feedstock resource, globally and by region, and to summarize relevant data that we believe others will 0nd useful, for example, those who are interested in producing biobased products such as lactic acid, rather than ethanol, from crops and wastes. The paper does not attempt to indicate how much, if any, of this waste material could actually be converted to bioethanol.
  • Authors:
    • Tan, C. S.
    • Reynolds, W. D.
    • Yang, X. M.
    • Drury, C. F.
  • Source: Soil & Tillage Research
  • Volume: 79
  • Issue: 1
  • Year: 2004
  • Summary: The influence of soil and crop management practices on soil aggregation is well documented; however very little information is available on the impact of aggregation on biological processes such as greenhouse gas emissions. Soils (Ap horizon of a Brookston clay loam) were sampled in the spring of 2002 from two treatments in a long-term study (established in 1959). The treatments included continuous corn (Zea mays L.) and the corn phase of a 4-year crop rotation which included corn-oats (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa. The continuous corn (CC) treatment was plowed every fall whereas the rotation corn (RC) treatment was plowed 2 out of the 4 years (in the fall following second year alfalfa and following corn). The objectives were to determine the impact of crop rotation and continuous corn on aggregate size distribution, and the influence of aggregate size on CO2 and N2O production through denitrification. The soil samples were separated into six aggregate size fractions (<0.25, 0.25-0.50, 0.50-1.0, 1.0-2.0, 2.0-4.0, and 4.0-8.0mm diameter) using a dry sieving procedure. Each aggregate size fraction was separated into two subsamples with one subsample left intact and the other ground to <0.15mm (100-mesh sieve). The intact and ground aggregates from each size fraction were incubated anaerobically using the acetylene inhibition technique and carbon dioxide (CO2) and nitrous oxide (N2O) production (denitrification) were determined. Nitrate was added and thus not limiting in the incubations. In both cropping treatments, the 2–4mm aggregate size was the dominant size fraction (~35-45% of the soil by weight) followed by the 1-2mm size fraction (~20-25% of the soil by weight). Crop rotation increased both CO2 and N2O production (denitrification) and the proportion of <2mm diameter aggregates compared to continuous corn. For intact aggregates, CO2 production decreased with increasing aggregate size, while N2O production (denitrification) increased with increasing aggregate size. When the aggregates were ground, CO2 production was independent of the original aggregate size, while N2O production (denitrification) decreased as the size of the original aggregates increased. This study demonstrates that both the size distribution of natural soil aggregates and soil grinding can have substantial impacts on the CO2 and N2O production through denitrification.
  • Authors:
    • Li, C.
    • Lemke, R. L.
    • Desjardins, R. L.
    • Smith, W. N.
    • Grant, B.
  • Source: Climatic Change
  • Volume: 65
  • Issue: 3
  • Year: 2004
  • Summary: The Denitrification-Decompostion (DNDC) model was used to estimate the impact of change in management practices on N2O emissions in seven major soil regions in Canada, for the period 1970 to 2029. Conversion of cultivated land to permanent grassland would result in the greatest reduction in N2O emissions, particularly in eastern Canada where the model estimated about 60% less N2O emissions for this conversion. About 33% less N2O emissions were predicted for a change from conventional tillage to no-tillage in western Canada, however, a slight increase in N2O emissions was predicted for eastern Canada. Greater N2O emissions in eastern Canada associated with the adoption of no-tillage were attributed to higher soil moisture causing denitrification, whereas the lower emissions in western Canada were attributed to less decomposition of soil organic matter in no-till versus conventional tilled soil. Elimination of summer fallow in a crop rotation resulted in a 9% decrease in N2O emissions, with substantial emissions occurring during the wetter fallow years when N had accumulated. Increasing N-fertilizer application rates by 50% increased average emissions by 32%,while a 50% decrease of N-fertilizer application decreased emissions by16%. In general, a small increase in N2O emissions was predicted when N-fertilizer was applied in the fall rather than in the spring. Previous research on CO2 emissions with the CENTURY model (Smith et al.,2001) allowed the quantification of the combined change in N2O andCO2 emissions in CO2 equivalents for a wide range of management practices in the seven major soil regions in Canada. The management practices that have the greatest potential to reduce the combined N2O and CO2 emissions are conversion from conventional tillage to permanent grassland, reduced tillage, and reduction of summer fallow. The estimated net greenhouse gas (GHG) emission reduction when changing from cultivated land to permanent grassland ranged from 0.97 (Brown Chernozem) to 4.24 MgCO2 equiv. ha-1 y-1 (Black Chernozem) for the seven soil regions examined. When changing from conventional tillage to no-tillage the net GHG emission reduction ranged from 0.33 (Brown Chernozem) to 0.80 Mg CO2 equiv. ha-1 y-1 (Dark Gray Luvisol). Elimination of fallow in the crop rotation lead to an estimated net GHG emission reduction of 0.43 (Brown Chernozem) to 0.80 Mg CO2 equiv.ha-1 y-1 (Dark Brown Chernozem). The addition of 50% more or 50% less N-fertilizer both resulted in slight increases in combined CO2 and N2O emissions. There was a tradeoff in GHG flux with greater N2O emissions and a comparable increase in carbon storage when 50% more N-fertilizer was added. The results from this work indicate that conversion of cultivated land to grassland, the conversion from conventional tillage to no-tillage, and the reduction of summerfallow in crop rotations could substantially increase C sequestration and decrease net GHG emissions. Based on these results a simple scaling-up scenario to derive the possible impacts on Canada's Kyoto commitment has been calculated.
  • Authors:
    • Arshad, M. A.
    • Franzluebbers, A. J.
    • Azooz, R. H.
  • Source: Soil & Tillage Research
  • Volume: 77
  • Issue: 1
  • Year: 2004
  • Summary: Conservation tillage has become a major soil management strategy to reduce soil erosion and improve soil quality, yet the impacts of crop rotation on soil responses to conservation tillage remain poorly described. We investigated the effects of (i) perennial grass cover versus annual cropping and (ii) type of break crop in a wheat (Triticum aestivum L.)-based crop rotation system on surface-soil (0-10 cm) structural and organic matter properties towards the end of a decade of continuous management on an Albic Luvisol in the cold, semiarid region of northwestern Canada. Soil aggregation was at state to resist water erosion more under perennial grass (i.e. bromegrass (Bromus inermis Leyss.) and red fescue (Festuca rubra L.)) than under annual cropping systems (mean-weight diameter of 2.1 and 1.6 mm under perennial and annual systems, respectively). Soil organic C was higher (44 g C kg-1 soil versus 38 g C kg-1 soil), but total soil N was lower (3.5 g N kg-1 soil versus 3.9 g N kg-1 soil) under perennial compared with annual cropping systems. There were few significant differences in soil-structural properties among the various annual cropping systems. The largest effect was greater light-fraction C and N under continuous wheat (4.0 g C kg-1 soil and 0.27 g N kg-1 soil) compared with other rotations, especially wheat-wheat-fallow (2.4 g C kg-1 soil and 0.16 g N kg-1 soil), as a result of higher residue inputs. Relationships between mean-weight diameter of water-stable aggregates and biochemical properties were strongest for soil microbial biomass C and soil organic C. Perennial grass cover exhibited greater potential to preserve soil-structural properties than no-tillage annual cropping.
  • Authors:
    • Massé, D.
    • Chiquette, J.
    • Benchaar, C.
    • Boadi, D.
  • Source: Canadian Journal of Animal Science
  • Volume: 84
  • Issue: 3
  • Year: 2004
  • Summary: Enteric methane (CH4) emission is a major contributor to Canadian greenhouse gas emissions, and also a loss of feed energy during production. The objective of this paper is to provide an update on current management practices and new dietary strategies recently proposed to reduce CH4 emissions from ruminants. Existing mitigation strategies for dairy, e.g., the addition of ionophores, fats, use of high-quality forages, and increased use of grains, have been well researched and applied. These nutritional changes reduce CH4 emissions by manipulating ruminal fermentation, directly inhibiting methanogens and protozoa, or by diverting hydrogen ions away from methanogens. Current literature has identified new CH4 mitigation options. These include the addition of probiotics, acetogens, bacteriocins, archaeal viruses, organic acids, plant extracts (e.g., essential oils) to the diet, as well as immunization, and genetic selection of cows. These new strategies are promising, but more research is needed to validate these approaches and to assess in vivo their effectiveness in reducing CH4 production by dairy cows. It is also important to evaluate CH4 mitigation strategies in terms of the total greenhouse gas budget and to consider the cost associated with the various strategies. More basic understanding of the natural differences in digestion efficiencies among animals as well as a better knowledge of methanogens and their interaction with other organisms in the rumen would enable us to exploit the potential of some of the new CH4 mitigation strategies for dairy cattle production.
  • Authors:
    • Lindwall, W.
    • Kulshreshtha, S.
    • Desjardins, R.
    • Junkins, B.
    • Boehm, M.
  • Source: Climatic Change
  • Volume: 65
  • Issue: 3
  • Year: 2004
  • Summary: Net greenhouse gas (GHG) emissions from Canadian crop and livestock production were estimated for 1990, 1996 and 2001 and projected to 2008. Net emissions were also estimated for three scenarios (low (L), medium (M) and high (H)) of adoption of sink enhancing practices above the projected 2008 level. Carbon sequestration estimates were based on four sink-enhancing activities: conversion from conventional to zero tillage (ZT), reduced frequency of summerfallow (SF), the conversion of cropland to permanent cover crops (PC), and improved grazing land management (GM). GHG emissions were estimated with the Canadian Economic and Emissions Model for Agriculture (CEEMA). CEEMA estimates levels of production activities within the Canadian agriculture sector and calculates the emissions and removals associated with those levels of activities. The estimates indicate a decline in net emissions from 54 Tg CO2-Eq yr-1 in1990 to 52 Tg CO2-Eq yr-1 in 2008. Adoption of thesink-enhancing practices above the level projected for 2008 resulted in further declines in emissions to 48 Tg CO2-Eq yr-1 (L), 42 TgCO2-Eq yr-1 (M) or 36 Tg CO2-Eq yr-1 (H). Among the sink-enhancing practices, the conversion from conventional tillage to ZT provided the largest C sequestration potential and net reduction in GHG emissions among the scenarios. Although rates of C sequestration were generally higher for conversion of cropland to PC and adoption of improved GM, those scenarios involved smaller areas of land and therefore less C sequestration. Also, increased areas of PC were associated with an increase in livestock numbers and CH4 and N2O emissions from enteric fermentation andmanure, which partially offset the carbon sink. The CEEMA estimates indicate that soil C sinks are a viable option for achieving the UNFCCC objective of protecting and enhancing GHG sinks and reservoirs as a means of reducing GHG emissions (UNFCCC, 1992).
  • Authors:
    • Schoenau, J.
    • Mohr, R.
    • McLaren, D.
    • Irvine, R.
    • Derksen, D.
    • Monreal, M.
    • Grant, C.
  • Source: Better Crops with Plant Food
  • Volume: 88
  • Issue: 2
  • Year: 2004
  • Summary: Field experiments were conducted at the Research Centre and the Zero-Till Farm, Manitoba, Canada, during 1999-2000, 2000-01 and 2001-01, wherein rape and spring wheat were sown using conventional tillage (CT) and no-till (NT) in the first year of study. The crops were supplemented with 0, 22 or 44 lb P 2O 5/acre, side-banded at sowing. After rape and spring wheat harvest, the stubble in the CT plots was tilled. In the second year, flax was sown into both stubbled and tilled plots, and supplemented with P fertilizer side-banded at 0 or 44 lb P 2O 5/acre. The roots were evaluated for mycorrhizal association at 5 weeks of growth and seed yield was collected at crop maturity. The P nutrition of flax was most influenced by the preceding crop in rotation, while tillage system and P fertilizer management had minor impact on flax. Comparative data on the effect of P fertilizer application to current year flax, previous crop type and P fertilizer management, and tillage system on mycorrhiza incidence and flax seed yield are tabulated.
  • Authors:
    • Arshad, M.
    • Soon, Y.
  • Source: Canadian Journal of Soil Science
  • Volume: 84
  • Issue: 4
  • Year: 2004
  • Summary: A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley ( Hordeum vulgare L.)-canola ( Brassica rapa L.)-field pea ( Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha -1) than canola following barley (non-legumes) (6 to 16% or 3 to 9 kg N ha -1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources.
  • Authors:
    • Harker, K. N.
    • Newman, J. C.
    • O'Donovan, J. T.
    • Clayton, G. W.
  • Source: Weed Technology
  • Volume: 18
  • Issue: 3
  • Year: 2004
  • Summary: Glyphosate-resistant canola was seeded at Vegreville, Alberta, in 1997 and 1999 and barley in rotation with the canola in 1998 at three seeding rates. The effects, at each crop seeding rate, of variable glyphosate (canola) and tralkoxydim plus bromoxynil plus MCPA (barley) rates on crop yield, net economic return and seed production by wild oat, wild mustard, and wild buckwheat, and the amount of weed seed in the soil seed bank was determined. Crop seeding rate influenced the response of canola and barley yield and weed seed production to herbicide rate. At the lowest crop seeding rates, yield responses tended to be parabolic with yields increasing up to one-half and three-quarters of the recommended herbicide rates and trends toward reduced yields at the full rates. This response was not evident at the higher crop seeding rates, where, in most cases the yield reached a maximum between one-half and the full recommended rate. The effects of the herbicides on weed seed production, especially at the lowest rate, were often superior at the higher crop seeding rates. The results indicate that seeding canola and barley at relatively high rates may reduce risk associated with lower crop yields and increased weed seed production at lower than recommended herbicide rates. However, the current cost of herbicide-resistant canola seed may preclude the adoption of this integrated weed management practice by growers.
  • Authors:
    • Philip, H.
    • Woods, S.
    • Weiss, R. M.
    • Olfert, O.
    • Dosdall, L.
  • Source: The Canadian Entomologist
  • Volume: 136
  • Issue: 2
  • Year: 2004
  • Summary: Cereal leaf beetle, Oulema melanopus L., is an invasive pest insect of small grain cereal crops, particularly oat, wheat, and barley. The first report of cereal leaf beetle populations in North America came from Michigan in 1962. Surveys indicate that populations have become established throughout eastern North America from Ontario to Alabama and in northwestern North America from Utah to southern British Columbia. The establishment of O. melanopus in western North America has raised concern that its presence is a potential risk to the Canadian cereal industry, especially in the prairie ecozone of western Canada, where up to 10 million hectares of cereal crops are grown annually. Field surveys to date have indicated that O. melanopus has not yet become established in this region. A CLIMEX(TM)model for O. melanopus in North America was developed, based on climate and ecological parameters, and validated with actual distribution records. The actual distribution of O. melanopus in eastern North America matched the predicted distribution well. The model predicts that, once introduced, O. melanopus would readily survive in the cereal-growing areas of western Canada and present a significant risk to cereal production. The potential for establishment of O. melanopus in the prairie ecozone of western Canada substantiates the efforts by regulatory agencies to prevent accidental introduction of this pest species.