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Institution

Agriculture and Agri-Food Canada

FacilityOttawa, Ontario, 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.
Topics: Population, Soil water, Manure, Tillage, Loam


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors measured fluxes of CO 2 in a tillage experiment that had been initiated in 1982 on a silt loam (Typic Haploboroll) in southwestern Saskatchewan.
Abstract: The traditional cropping system in semiarid regions of the Canadian prairies involves frequent summer fallowing with several tillage operations to control weeds during the fallow period. Recently, there has been a trend toward reduced tillage and more intensive cropping, but the impact of this shift in management on sequestration of atmospheric CO 2 remains uncertain. In 1995 and 1996, we measured fluxes of CO 2 in a tillage experiment that had been initiated in 1982 on a silt loam (Typic Haploboroll) in southwestern Saskatchewan. The experiment comprised two spring wheat (Triticum aestivum L.) rotations (continuous wheat [Cont. W] and fallow-wheat [F-W]), each with conventional tillage (CT) and no-till (NT) treatments. In Cont. W, CO 2 fluxes tended to be lower under NT than under CT (mean annual flux was 20 to 25% less for NT than CT). In F-W, tillage effects on mean annual CO 2 flux were significant (P < 0.05) in the wheat phase only (NT 10% less than CT). Tillage had negligible effect on C inputs in crop residues. lower CO 2 fluxes under NT than under CT were attributed to slower decomposition of crop residues placed on the surface of NT soil than when they were incorporated. With good growing conditions (and thus large inputs of residues) between 1989 and 1996, there was an accumulation of partially decomposed residues on the surface of NT soil. Carbon in surface residues represented about one-half of the C gained by NT soil. In Cont. W, surface residue C (in 1996) amounted to 3.6 t ha -1 under NT vs 1.4 t ha -1 under CT. Residue C amounts were smaller in the F-W system: 1.7 t ha -1 (NT) and 0.7 t ha -1 (CT). Based on our results, producers on medium-textured soils in the semiarid Canadian prairies who switch from the traditional wheat production system (conventionally tilled fallow-wheat) to continuous no-till cropping could, potentially, sequester 5 to 6 t C ha -1 in soil organic matter and surface residues in 13 to 14 yr.

198 citations

Journal ArticleDOI
TL;DR: The results illustrate that some measures of feeding behavior are highly repeatable within cows, but variable between cows and across stages of lactation, and tests of treatment effects on feeding behavior should be within cow and control for days in milk.

198 citations

Journal ArticleDOI
TL;DR: The potential for micropollutant uptake into crops under normal farming conditions is low, according to this study, which suggests that a one-year offset between biosolid application and the harvest of crops for human consumption is required.

198 citations

Journal ArticleDOI
TL;DR: The targeted denitrifier communities responded similarly to the different plant residues under the conditions tested despite changes in the quality of organic C and different C:N ratios.
Abstract: In agricultural cropping systems, crop residues are sources of organic carbon (C), an important factor influencing denitrification. The effects of red clover, soybean, and barley plant residues and of glucose on denitrifier abundance, denitrification gene mRNA levels, nitrous oxide (N2O) emissions, and denitrification rates were quantified in anoxic soil microcosms for 72 h. nosZ gene abundances and mRNA levels significantly increased in response to all organic carbon treatments over time. In contrast, the abundance and mRNA levels of Pseudomonas mandelii and closely related species (nirSP) increased only in glucose-amended soil: the nirSP guild abundance increased 5-fold over the 72-h incubation period (P < 0.001), while the mRNA level significantly increased more than 15-fold at 12 h (P < 0.001) and then subsequently decreased. The nosZ gene abundance was greater in plant residue-amended soil than in glucose-amended soil. Although plant residue carbon-to-nitrogen (C:N) ratios varied from 15:1 to 30:1, nosZ gene and mRNA levels were not significantly different among plant residue treatments, with an average of 3.5 10 7 gene copies and 6.9 10 7 transcripts g 1 dry soil. Cumulative N2O emissions and denitrification rates increased over 72 h in both glucose- and plant-tissue-C-treated soil. The nirSP and nosZ communities responded differently to glucose and plant residue amendments. However, the targeted denitrifier communities responded similarly to the different plant residues under the conditions tested despite changes in the quality of organic C and different C:N ratios.

198 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluate the comparability and reproducibility of methods employed in six laboratories including batch, kinetic, and bioreactor methods to measure the biodegradable fraction of dissolved organic matter (BDOC) in soils.
Abstract: The importance of dissolved organic matter (DOM) in many soil processes is determined in large part by its availability to microbial uptake and decomposition, as this biodegradation can yield both energy and limiting nutrients Despite its importance in soil ecology, there are no standard approaches to measuring the biodegradable fraction of DOC (BDOC) in soils Here, we evaluate the comparability and reproducibility of methods employed in six laboratories including batch, kinetic, and bioreactor methods Solutions from a variety of sources (throughfall, soil solution and soil extracts) were analysed using methods typically employed in each of the six participating laboratories Our results show that the precision of various BDOC methods was similar (5–15%) across a broad range of BDOC (from 12% to 56% of total DOC) Differences in mean BDOC for the various test solutions were statistically significant when results were pooled across all the methods, and only a 90-day incubation resulted in consistently higher values for BDOC than the other methods For 4 of 6 test solutions, measured BDOC increased by 6–13% with added nutrients Current methods produce largely comparable results, providing the justification for comparisons among existing data sets collected with different methodologies We recommend two standard methods for future studies: (1) a rapid determination of relatively labile DOC (measurement of DOC removal after 7 days of incubation with added nutrients) and (2) a 42-day incubation with repeated analysis of CO2 production when determination of decomposition rate constants and a labile and relatively refractory component of DOC is desired

198 citations


Authors

Showing all 10964 results

NameH-indexPapersCitations
Fereidoon Shahidi11995157796
Miao Liu11199359811
Xiang Li97147242301
Eviatar Nevo9584840066
Tim A. McAllister8586232409
Hubert Kolb8442025451
Daniel M. Weary8343722349
Karen A. Beauchemin8342322351
Nanthi Bolan8355031030
Oene Oenema8036123810
Santosh Kumar80119629391
Yueming Jiang7945220563
Denis A. Angers7625619321
Tong Zhu7247218205
Christophe Lacroix6935315860
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202314
202282
20211,078
20201,035
2019992
2018988