Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

Lignin Extraction from Straw by Ionic Liquids and Enzymatic Hydrolysis of the Cellulosic Residues

Abstract: Lignocellulose is a promising starting material for bioproducts, ranging from biofuels to specialty chemicals; however, lignocellulose is resistant to enzymatic degradation. Overcoming this resistance is therefore an important priority for the development of the lignocellulosic biorefinery concept. In this work, 1-ethyl-3-methylimidazolium acetate ([emim]Ac) was selected from six ionic liquid candidates for the extraction of lignin from triticale and wheat straw and flax shives. Lignin extractability, composition, and cellulose enzymatic digestibility of the residues after extraction by [emim]Ac were determined at various temperatures (70−150 °C) and time intervals (0.5−24 h). The optimal result (52.7% of acid insoluble lignin in triticale straw) was obtained at 150 °C after 90 min, yielding >95% cellulose digestibility of the residue. Little cellulose was extracted, and the extracted lignin was recovered by acid precipitation. Selective extraction of lignin by ionic liquids is a potentially efficient tec...

Crop residue influence on denitrification, N2O emissions and denitrifier community abundance in soil

Abstract: Bacterial denitrification plays an important role in the global nitrogen cycle and is a principal contributor of nitrous oxide (N2O) to the atmosphere. The influence of simple (glucose) and complex (red clover and barley residue) carbon (C) sources on the amount of denitrification, N2O molar ratio (N2O:(N2 + N2O)), and abundance of soil total bacterial and denitrifier communities was investigated using repacked soil cores. Quantitative PCR was used to determine the abundance of the total bacterial community (16S rRNA gene) and components of the denitrifier community, cnorBP (Pseudomonas mandelii and related species), cnorBB (Bosea/Bradyrhizobium/Ensifer spp.) and nosZ gene bearing communities. The relationship between the supply of, and demand for, terminal electron acceptors (TEAs), as determined by the relative availability of C and nitrate (NO3−), influenced the amount of denitrification and the N2O molar ratio for both simple and complex C sources. Addition of glucose and red clover to the soil increased microbial activity, leading to NO3− depletion and an increased consumption of N2O, whereas in soil amended with barley straw, there was not sufficient stimulation of microbial activity to create sufficient TEA demand to cause a measurable increase in emissions. This resulted in a higher N2O molar ratio at the end of the incubation for the barley straw amended soil. A significant relationship (R2 = 0.83) was found between respiration and cumulative denitrification, suggesting that the available C increased microbial activity and O2 consumption, which led to conditions favorable for denitrification. The source of C did not significantly affect the total bacterial community or the nosZ copy numbers with an average of 4.9 × 107 16S rRNA gene copies g−1 dry soil and 4.6 × 106 nosZ gene copies g−1 dry soil, respectively. The addition of red clover plus NO3− significantly increased the cnorBP denitrifier community in comparison with the unamended control while the density of the cnorBP denitrifier community increased from 3.9 × 104 copies g−1 dry soil to a maximum of 8.7 × 105 copies g−1 dry soil following addition of glucose plus NO3− to soil. No significant correlations were found between the denitrifier community densities and cumulative denitrification or N2O emissions, suggesting that the denitrification activity was decoupled from the denitrifier community abundance.

Widespread Use and Frequent Detection of Neonicotinoid Insecticides in Wetlands of Canada's Prairie Pothole Region

Abstract: Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ∼11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples. In spring 2012 prior to seeding, 36% of wetlands contained at least one neonicotinoid. Detections increased to 62% in summer 2012, declined to 16% in fall, and increased to 91% the following spring 2013 after ice-off. Peak concentrations were recorded during summer 2012 for both thiamethoxam (range:

Review: Ammonia emissions from dairy farms and beef feedlots1

Abstract: Hristov, A. N., Hanigan, M., Cole, A., Todd, R., McAllister T. A., Ndegwa, P. and Rotz, A. 2011. Review: Ammonia emissions from dairy farms and beef feedlots. Can. J. Anim. Sci. 91: 1–35. Ammonia emitted from animal feeding operations is an environmental and human health hazard, contributing to eutrophication of surface waters and nitrate contamination of ground waters, soil acidity, and fine particulate matter formation. It may also contribute to global warming through nitrous oxide formation. Along with these societal concerns, ammonia emission is a net loss of manure fertilizer value to the producer. A significant portion of cattle manure nitrogen, primarily from urinary urea, is converted to ammonium and eventually lost to the atmosphere as ammonia. Determining ammonia emissions from cattle operations is complicated by the multifaceted nature of the factors regulating ammonia volatilization, such as manure management, ambient temperature, wind speed, and manure composition and pH. Approaches to quanti...