bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation of parasitological and immunological parameters in sheep with high and low resistance to haemonchosis
Authors: Muñoz-Guzmán M. A. , Cuéllar-Ordaz J. A. , Valdivia-Anda A. G. , Buendía-Jiménez J. A. , Alba-Hurtado F.
Published: April 2011

Parasitological and immunological parameters of Blackbelly (Bb), a haemonchosis high-resistance sheep breed, and Columbia (Cb) a haemonchosis low-resistance breed were compared. Two experiments were performed: Bb and Cb lambs were infected weekly with 1000 third-stage larvae (L3) of Haemonchus contortus for 6 wk. In the first experiment, faecal egg counts (FEC) and blood eosinophils (BE) were determined for 15 wk. In the second experiment, the following parameters were measured weekly: FEC, plasma proteins, serum IgG to H. contortus L3 levels by ELISA and L3 antigens recognized by Western blot; animals were euthanized after 15 weeks and autopsies were performed to evaluate the total adult phases (AP), eosinophils and mast cells in the fundic abomasal region (FAR), pyloric abomasal region (PAR) and abomasal lymph node (ALN). Fecal egg counts and AP were significantly higher (P < 0.05) in Cb lambs. BE showed a significant increase (P < 0.05) in both breeds at week 9 and, subsequently, Cb lambs presented a sudden decrease in these levels. The Bb lambs revealed a higher amount (P < 0.05) of antibodies between weeks 9 and 15 of the experiment, and Cb lambs showed a reduction in antibody levels at week 9. The Western blot revealed 11 bands of H. contortus L3 antigens; no differences were observed between breeds. The number of tissue eosinophils per cm2 in PAR and ALN was higher (P < 0.05) in the Bb lambs. No differences were found (P > 0.05) in the number of mast cells per cm2 in the sampled regions of both infected groups. The increase and maintenance of serum antibodies and circulating and local eosinophils in resistant animals agrees with the development and maintenance of a Th2 type immune response. The initial increase and further reduction of serum antibodies and circulating and local eosinophils in the low-resistance lamb breed suggest an initial Th2 type response and a subsequent change to a Th1 type response. Key words: Haemonchus, immune response, breed resistence, eosinophils, antibodies, sheep
Effects of source of rumen fluid on in vitro dry matter digestibility of feeds determined using the DAISYII incubator
Authors: King J. , Plaizier J. C.
Published: April 2011

Apparent (ADD) and true (TDD) in vitro dry matter digestibilities of 12 ruminant feeds were determined with the DAISYII incubator (ANKOM Technology Corp. Macedon, NY) using inoculum prepared from ruminal fluid obtained from steers fed grass hay or from cows fed total mixed ration (56% forage and 44% grain, DM basis). Inoculum source did not affect ADD and TDD. Averaged across feeds and sources of inoculum, ADD was 6.7 percentage points lower than TDD. Key words: In vitro dry matter digestibility, ruminant feeds, inoculum, ANKOM DAISYII incubator
Hormonal response to dietary L-arginine supplementation in heat-stressed sows
Authors: Pérez Laspiur J. , Farmer C. , Kerr B. J. , Zanella A. , Trottier N. L.
Published: April 2011

The response of key metabolic hormones to dietary arginine supplementation in heat-stressed lactating sows was determined. Sixty-three sows were exposed to a thermoneutral (TN = 20°C) or hot (HT = 29.4°C) environmental temperature, and were fed diets containing 0.96% (control, C), 1.34% (medium, ME) or 1.73% (high, HI) arginine. Blood samples were obtained 2 h postprandially on days 7, 14, and 21 of lactation and concentrations of insulin, glucose, growth hormone (GH) and prolactin were determined. Arginine supplementation increased insulin concentrations (P < 0.01) on day 14 of lactation, had no effect (P > 0.1) on glucose, and decreased (P < 0.05) GH with ME compared with C diets. There was a temperature × diet interaction (P < 0.05) for prolactin, with values being greater for the C compared with the ME and HI diets at 29.4°C, but being lower at 20°C.There was no effect (P > 0.1) of temperature alone on any of the measured variables. Results indicate that arginine supplementation may mediate improvements in nutrient utilization by regulating the metabolism of both insulin and GH in lactating sows. Key words: Arginine, growth hormone, heat stress, insulin, lactation, prolactin, sow
Enteric methane emissions from growing beef cattle as affected by diet and level of intake
Authors: Beauchemin Karen A , McGinn Sean M
Published: April 2011

A study was conducted to determine whether enteric methane (CH4) emissions from growing feedlot cattle fed backgrounding diets based on barley silage could be reduced through grain supplementation. A second objective was to determine the effects of feed intake on CH4 emissions. Eight Angus beef heifers (initial and final body weight, 328 ± 28 and 430 ± 29 kg) were used. The experiment was designed as a split-plot crossover with two diets and two 8-week periods. The main plot was the diet [dry matter (DM) basis]: high forage (70% barley silage, 30% barley-based concentrate) or high grain (30% barley silage, 70% corn-based concentrate). The sub-plot was the feeding level: unrestricted (ad libitum feed intake, 5% orts) or restricted (65% of ad libitum intake) feed intake. Methane emissions were measured during each sub-plot over 3 d using whole animal chambers. Changing the forage to concentrate ratio and substituting barley for corn did not affect CH4 emissions (141.5 g d-1; P = 0.26), and the average emission was about 10% higher than the emission calculated using the International Panel on Climate Change (IPCC) Tier 1 approach. Methane conversion rate was also similar for both diets [6.23% of gross energy intake (GEI), P = 0.29], and was similar to the value of 6.0 used in the IPCC Tier 2 approach to calculating CH4 emissions from cattle. Restricting intake reduced CH4 emissions (169 vs. 114 g d-1; P < 0.002), with the reduction in CH4 proportional to the decline in intake. Level of intake relative to maintenance energy requirements was moderately inversely related (r = -0.30; P = 0.04) to CH4 (% GEI). The proportion of GEI lost as CH4 declined by 0.77 percentage units per unit increase in level of intake above maintenance. This study shows that supplementing barley-silage-based diets with corn grain to increase diet quality has only small effects on reducing CH4 emissions. In contrast, maximizing feed intake above maintenance energy requirements increases daily CH4 emissions, but improves efficiency of CH4 conversion because CH4, as a percentage of GEI, declined. Thus, feeding cattle for maximum gain is an important CH4 mitigation strategy for the cattle industry as it reduces the proportion of feed energy lost as CH4 each day, as well as, reduces the number of days to market and associated CH4 production. Key words: Cattle, methane, greenhouse gasses
Effect of sub-therapeutic antibiotics and auction exposure on health, performance, and feeding behavior of weaned calves
Authors: Gibb D. J. , Schwartzkopf-Genswein K. S. , McAllister T. A. , Genswein B. M. A. , Streeter M.
Published: April 2011

Calves sourced directly from a ranch were heavier initially (273 vs. 258; P = 0.01) than calves from the same ranch but processed through an auction barn. For calves fed 6 g head-1 d-1 chlortetracycline from days 5 to 9, feeding an additional 350 mg head-1 d-1 of chlortetracycline and sulfamethazine from days 1 to 28 improved gain/feed (P = 0 .03), but only for the first 28 d of the 84-d trial. Frequency of bunk visits were altered by calf source and antibiotic treatment. Key words: Antibiotics, auction, calves, feedlot receiving programs
Blood metabolites and fatty acid composition of milk and cheese from ewes fed oilseeds
Authors: Zhang R. H. , Mustafa A. F. , Zhao X.
Published: April 2011

Sixteen lactating Dorset ewes were used in a completely randomized design to determine the effects of oilseed supplementation on milk yield and composition, blood metabolites, cheese yield and composition and fatty acid profile of milk and cheese. Four iso-nitrogenous diets were formulated: a control diet (CT) with no oilseed supplementation, a flaxseed supplemented diet (FS), a sunflower seed supplemented diet (SF), and a canola seed supplemented diet (CS). Oilseed-supplemented diets were formulated to contain 7% fatty acids. Feeding oilseeds had no effect on dry matter intake. Milk yield was similar for ewes fed CT, FS and SF and was higher (P < 0.05) than that of ewes fed CS. Ewes fed oilseed-supplemented diets produced milk with higher (P < 0.05) protein and total solid percentages than those fed CT. However, milk fat percentage was only higher (P < 0.05) in the milk of ewes fed FS and SF relative to those fed CT. Actual cheese yield was higher (P < 0.05) from milk of ewes fed oilseed-supplemented diets relative to those fed CT. However, cheese composition was not affected by dietary treatments. Plasma concentrations of fatty acids and cholesterol were increased (P < 0.05) while plasma concentration of β-hydroxybutyrate (βHBA) was decreased (P < 0.05) by oilseed supplementation. However, plasma concentrations of glucose and mammary extraction rate of plasma metabolites were not influenced by oilseed feeding. Oilseed supplementation increased (P < 0.05) concentrations of unsaturated fatty acids in milk fat. The order of increase was SF > FS > CS. Feeding SF, FS and CS increased (P < 0.05) conjugated linoleic acid (CLA) concentration in milk by 83.5, 39.2 and 16.5%, respectively. Concentration of linolenic acid in milk was only increased (P < 0.05) by feeding FS. Changes in milk fatty acid profiles were reflected in the cheese. Key words: Ewes, oilseeds, milk, cheese, fatty acids
The effects of handling and group size on welfare of pigs in lairage and their influence on stomach weight, carcass microbial contamination and meat quality
Authors: Rabaste C. , Faucitano L. , Saucier L. , Mormède P. , Correa J. A. , Giguère A. , Bergeron R.
Published: April 2011

At unloading and on the way to stunning, 800 barrows were exposed to either gentle handling (GH: slowly with a plastic board or whip) or rough handling (RH: quickly with an electric prod). Pigs were kept in large or small groups (30 or 10 pigs) during lairage. Compared with GH, RH increased climbing (P < 0.05), slipping (P < 0.01) and turning around (P < 0.001) behaviours during unloading, and climbing (P < 0.05) on the way to stunning. RH also reduced drinking behaviour during lairage (P < 0.01). Pigs kept in large groups were observed more often standing (P < 0.05) and fighting (P < 0.001) than pigs kept in small groups, but, in contrast, had a slightly lower level of urinary cortisol at slaughter. Stomach weight and microbial contamination at slaughter were not affected by treatments. RH tended to increase skin bruise score on the carcass (P < 0.06) and produced more exudative meat (P < 0.05). In conclusion, the response of pigs to the two specific stressors applied prior to slaughter in this study did not seem to contribute to stomach weight variation at slaughter, but it did influence pork quality. Key words: Pigs, pre-slaughter handling, group size, stress, stomach weight, microbial contamination, behaviour, meat quality
Nutritional suitability of viscid and whitethorn acacia for ruminants
Authors: Ishaque Muhammad , Beck Reldon F , Pieper Rex D
Published: April 2011

Leaves and pods of viscid acacia (Acacia neovernicosa Isley) and whitethorn acacia (Acacia constricta Benth) shrubs were analyzed for their nutritional suitability for livestock and wildlife. Leaves and pods were collected in mid-summer and at the end of the growing season in 1993 and 1994 from two sites in southern New Mexico in the Chihuahuan Desert. Chemical composition was determined by standard laboratory procedures. Pods of both species generally contained more crude protein, and phosphorus than the leaves. The difference in protein content between leaves and pods was not as great for whitethorn acacia as for viscid acacia. Calcium content of leaves for both species in 1994 (a drought year) was nearly double the calcium content measured in 1993 (near average precipitation). The amounts of crude protein, phosphorus and calcium in leaves and pods were adequate to meet the nutrient requirements of young immature animals and lactating females of livestock and wildlife during the summer and fall seasons. However, besides having thorns, both species also have secondary compounds including tannins and phenols, which reduce palatability and may limit intake and negate any benefit of the high crude protein content. Although a direct comparison was not possible, whitethorn acacia appears to have a higher potential forage value than viscid acacia because of higher protein content and lower tannin and phenol content. In southern New Mexico, desert grasslands, once common, are today dominated by many shrub species of low palatability. Both viscid acacia and whitethorn acacia species appear to have palatabilities similar to or higher than the two most common shrubs on these desert rangelands, mesquite (Prosopis glandulosa Torrey) and creosotebush [Larrea tridentata (D. C.) Coville]. With the continued decrease of herbaceous forage on these rangelands, and the continued expansion of the populations of these two acacia species, both have the potential to become more valuable as browse components in the diets of grazing animals. Key words: Viscid acacia, whitethorn acacia, crude proteins, condensed tannins, total phenolics, Chihuahuan Desert
Optimizing harvest schemes to improve yield and feeding quality in chickpea
Authors: Gan Yantai , Iwaasa Alan D , Fernandez Myriam R , McVicar Ray
Published: April 2011

Late maturity often causes substantial losses in yield and quality of chickpea (Cicer arietinum L.) in the short growing season in western Canada. This study determined optimum harvest management practices to minimize losses due to late maturity. Kabuli chickpea was grown in southwestern Saskatchewan from 2002 to 2004, and seed and straw were harvested with various harvest management practices. Seed yield in 2004 was higher compared with 2002 and 2003, but the 2004 seed samples had a high percentage of shrivelled and green seeds. Seed yield, weight per seed and harvest index (HI) were highest when the crop was directly combined at natural maturity either before or after a killing (-5°C) frost. On average, swathing at early or late maturity stages decreased seed yield, weight per seed and HI significantly compared with direct combine practices. Seeds from the swathing treatments had high percentages of green and shrivelled seeds with high levels of fungal colonization. Both seed and straw from swathing had the poorest feeding quality measured as neutral detergent fibre, acid detergent fibre, and organic matter content and digestibility. Desiccation of chickpea plants with Reglone or low dosages of glyphosate when 80% of pods had turned colour did not advance plant maturity, nor did they affect seed yield or HI compared with direct combine practices. It is concluded that in the short growing season in western Canada, harvest of chickpea at natural maturity either prior to or after a killing frost may optimize the seed yield and quality. Regardless of harvest practices, the quality of both seed and straw in chickpea may be suitable as salvage feed materials for beef livestock. Key words: Cicer arietinum, desiccation, direct-combine, maturity, glyphosate stress, swath, salvage feed
Impact of agronomic factors on seed yield formation and quality in flax
Authors: Lafond G. P. , Irvine B. , Johnston A. M. , May W. E. , McAndrew D. W. , Shirtliffe S. J. , Stevenson F. C.
Published: April 2011

Flaxseed is known to have significant health benefits in human nutrition and when included in animal rations. There is pressing need to improve flaxseed production to meet the growing demand. The objective was to study the effects of three seeding rates (22, 45 and 67 kg ha-1), two seeding dates (early May and late May), three rates of nitrogen (66, 100 and 133% of recommended) and three cultivars (Norlin, AC McDuff and CDC Valour) and at five locations representative of the flax-growing area of the Canadian prairies from 1999 to 2001. The variables of interest were plant density, seed yield and yield formation, seed oil content and oil quality. Plant establishment was always highest with Norlin, but bolls m-2 was similar between the three cultivars. Plant density was always highest with the later plantings. No overall effect of seeding date was observed on grain yield, but the site-year by seeding date interaction showed that the later planting was favoured by the most northerly sites and early planting at the most southerly sites. The sites intermediate in latitude showed little response to seeding date. This finding provides important information with respect to the inclusion of flax in cropping systems depending on the latitude and deciding on the order of planting. Later planting resulted in a small decrease in oil content. Seed yields were increased with seeding rates going from 22 to 45 kg ha-1, which corresponded to plant populations > 300 plants m-2, with no increases thereafter. Increases in seeding rates always reduced the number of bolls plant-1 with little effect on seeds boll-1. Seeding rate had no effect on seed oil quantity and quality and maturity. A seed yield increase was observed with nitrogen when going from 66 to 100% of the recommended rate with no increases past 100%. Adding nitrogen resulted in a small drop in seed oil content. The seeding date × nitrogen rate interaction revealed a lack of response to nitrogen with the later planting date beyond 66% of the recommended N rate, suggesting reduced nitrogen rates with later plantings are possible. The absence of a site-year by seeding date by nitrogen rate interaction implies that findings of this study can be applied to a wide geographical area. In conclusion, attention needs to be given to seeding rates to target plant density > 300 plants m-2. Even with the high seeding rates, the target plant population was achieved only 60 and 73% of the time for the early and late planting, respectively. Using soil test recommendations for nitrogen will maximize seed yields under most situations. Best agronomic practices to maximize seed yield were found to maintain adequate seed oil quality and quantity. Key words: Linum usitatissimum L., nitrogen rate, seeding rate, seeding date, cultivar
Development of a method to determine carotenoid composition of fresh forages
Authors: Cardinault N. , Lyan B. , Doreau M. , Chauveau B. , Rock E. , Grolier P.
Published: April 2011

Due to the limited interest in carotenoids in ruminant diets until recently, analyses of forages are often incomplete, focusing mainly on β-carotene and lutein. Carotenoid composition of green forage from middle mountain meadow was analyzed by HPLC after extraction and elimination of chlorophylls by mild saponification. This method of analysis uses two C18 columns in series with a quaternary gradient system. Our method allowed, for the first time, the identification and quantification of several xanthophylls other than lutein (i.e., violaxanthin, antheraxanthin, epilutein) in chlorophyll-free extracts from carotenoid-rich forage. The intra-day (3.5–7.5 %) and inter-day (1.2–3.5 %) coefficients of variation are suitable for routine determination of carotenoids in green forage. This method could also be used in metabolic studies of these micronutrients in ruminants. Key words: Xanthophylls, carotenoids, fresh forage, HPLC
Katrina Soybean
Authors: Fischer J. D. , Stirling B. T. , Ablett G. R.
Published: April 2011

Katrina is a 2950 crop heat unit (CHU) soybean [Glycine max (L.) Merrill] cultivar with excellent yield potential, good lodging resistance and above average seed size and seed protein levels. It was developed by the Ridgetown Campus, University of Guelph, and is adapted to the 2900–3100 CHU areas of Ontario. Katrina was issued registration number 6015 on 205 Nov. 28 by the Variety Registration Office, Plant Production Division of the Canadian Food Inspection Agency. Key words: Soybean, cultivar description
Post-emergence application of N fertilizer to improve grain yield and quality of irrigated durum and bread wheat
Authors: Beres B. L. , Bremer E. , Sadasivaiah R. S. , Clarke J. M. , Graf R. J. , McKenzie R. H. , Dyck R. J.
Published: April 2011

Field studies were conducted for 3 yr (2001 to 2003) at two irrigated sites in southern Alberta to determine if post-emergence N application (38 kg N ha-1) was warranted for durum (Triticum turgidum L.) and bread wheat (T. aestivum) in soils with relatively high N. Greater efficacy occurred with in-crop surface-applied granular ammonium nitrate (AN) compared with foliar-applied urea-ammonium-nitrate (UAN) solution. Early AN application usually improved grain yield compared with the fertilized control (38 k g N ha-1 applied at seeding), while late application reduced grain yield, but increased grain protein concentration and end-use quality. Key words: Triticum turgidum, Triticum aestivum, nitrogen fertilizer, foliar, timing, split N, grain protein concentration
The relationship of LT50 to prolonged freezing survival in winter wheat
Authors: Skinner D. Z. , Garland-Campbell K. A.
Published: April 2011

Twenty-six wheat (Triticum aestivum L.) lines were tested for their ability to withstand remaining frozen for extended periods of time. Survival of acclimated seedlings was evaluated after remaining frozen at -5°C for 15 or 20 wk. Survival after 15 wk ranged from 0 to 100% and after 20 wk ranged from 0 to 33%. The relationship of survival and LT50 scores, the temperatures at which 50% of the plants were predicted to die, was examined with linear regression analysis. The linear relationship was highly statistically significant after 15 wk and after 20 wk. The cultivars Norstar and Froid survived being frozen for 20 wk nearly twice as well as the other cultivars; about 33% vs. 17% for the next best cultivar. These results indicated that the LT50 score, which can be estimated in about 8 wk, reliably predicts the ability to survive in the frozen state for as long as 20 wk, and that Norstar and Froid possess a long-term freezing tolerance mechanism that is far superior to the other cultivars tested. Key words: Winter wheat, freezing tolerance, freezing injury
Winmor pinto bean
Authors: Balasubramanian P. M. , Kiehn F. A. , Mündel H. -H. , Conner R. L. , Huang H. C.
Published: April 2011

Winmor is an early-maturing, partially upright pinto bean (Phaseolus vulgaris L.) with high yield potential and an average seed weight of 35.8 g 100 seeds-1. Winmor was developed at the Agriculture and Agri-Food Canada (AAFC) Research Station, Morden, MB, in collaboration with the AAFC Research Centre, Lethbridge, AB. Winmor is well adapted to the Canadian prairies, especially for production in southern Manitoba. Winmor is resistant to anthracnose race 73 [caused by Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib.], the predominant race in Manitoba. Winmor is susceptible, as is the check cultivar AC Pintoba, to white mould [caused by Sclerotinia sclerotiorum (Lib.) de Bary] and common bacterial blight [caused by Xanthomonas axonopodis pv. phaseoli (Smith) Vauterin et al. (Xap)]. Key words: Pinto bean, cultivar description, anthracnose resistance, early maturity
CDC Prosper field pea
Authors: Warkentin Tom , Vandenberg Albert , Tar’an Bunyamin , Banniza Sabine , Bett Kirstin , Barlow Brent , Ife Scott
Published: April 2011

CDC Prosper, a yellow cotyledon field pea (Pisum sativum L.) cultivar, was released in 2008 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Prosper has a semileafless leaf type, good lodging resistance, powdery mildew resistance, small-sized, round seeds, and good yielding ability. CDC Prosper is adapted to the field pea growing regions of western Canada. Key words: Field pea, Pisum sativum L., cultivar description
Effect of fertilizer nitrogen management on N2O emissions in commercial corn fields
Authors: Zebarth B J , Rochette P. , Burton D L , Price M.
Published: April 2011

This study examined the effect of rate and time of fertilizer N application to corn on N2O emissions in 2 yr on commercial corn fields. All treatments received starter fertilizer at 45 and 59 kg N ha-1 in 2004 and 2005, respectively, similar to grower practice. Treatments included a control, with no additional fertilizer N application, 75 or 150 kg N ha-1 banded at sidedress or 150 kg N ha-1 broadcast at emergence. There was no significant effect of N fertility treatment on corn grain or silage yield, indicating that all N applications were at or in excess of crop N requirement. Delay of fertilizer application to sidedress and reduced fertil izer N application were effective in reducing nitrate intensity, an index of soil nitrate availability calculated as the summation of daily soil NO3−-N concentration for the 0- to 15-cm depth. However, there was no significant effect of N fertility treatment on cumulative N2O emissions, and nitrate intensity explained a small proportion of the variation in cumulative N2O emissions. This study provides evidence that improved fertilizer N management may not result in reduced N2O emissions under some conditions. Key words: Zea mays, nitrate, denitrification, carbon availability, soil aeration
Nitrous oxide and carbon dioxide emissions from monoculture and rotational cropping of corn, soybean and winter wheat
Authors: Drury C F , Yang X M , Reynolds W D , McLaughlin N B
Published: April 2011

It is well established that nitrous oxide (N2O) and carbon dioxide (CO2) emissions from agricultural land are influenced by the type of crop grown, the form and amount of nitrogen (N) applied, and the soil and climatic conditions under which the crop is grown. Crop rotation adds another dimension that is often overlooked, however, as the crop residue being decomposed and supplying soluble carbon to soil biota is usually from a different crop than the crop that is currently growing. Hence, the objective of this study was to compare the influence of both the crop grown and the residues from the preceding crop on N2O and CO2 emissions from soil. In particular, N2O and CO2 emissions from monoculture cropping of corn, soybean and winter wheat were compared with 2 -yr and 3-yr crop rotations (corn-soybean or corn-soybean-winter wheat). Each phase of the rotation was measured each year. Averaged over three growing seasons (from April to October), annual N2O emissions were about 3.1 to 5.1 times greater in monoculture corn (2.62 kg N ha-1) compared with either monoculture soybean (0.84 kg N ha-1) or monoculture winter wheat (0.51 kg N ha-1). This was due in part to the higher inorganic N levels in the soil resulting from the higher N application rate with corn (170 kg N ha-1) than winter wheat (83 kg N ha-1) or soybean (no N applied). Further, the previous crop also influenced the extent of N2O emissions in the current crop year. When corn followed corn, the average N2O emissions (2.62 kg N ha-1) were about twice as high as when corn followed soybean (1.34 kg N ha-1) and about 60% greater than when corn followed winter wheat (1.64 kg N ha-1). Monoculture winter wheat had about 45% greater CO2 emissions than monoculture corn or 51% greater emissions than monoculture soybean. In the corn phase, CO2 emissions were greater when the previous crop was winter wheat (5.03 t C ha-1) than when it was soybean (4.20 t C ha-1) or corn (3.91 t C ha-1). Hence, N2O and CO2 emissions from agricultural fields are influenced by both the current crop and the previous crop, and this should be accounted for in both estimates and forecasts of the emissions of these important greenhouse gases. Key words: Denitrification, soil respiration, rotation, crop residue
Influence of fertilizer nitrogen source and management practice on N2O emissions from two Black Chernozemic soils
Authors: Burton D L , Li Xinhui , Grant C A
Published: April 2011

Fertilizer nitrogen use is estimated to be a significant source of nitrous oxide (N2O) emissions in western Canada. These estimates are based primarily on modeled data, as there are relatively few studies that provide direct measures of the magnitude of N2O emissions and the influence of N source on N2O emissions. This study examined the influence of nitrogen source (urea, coated urea, urea with urease inhibitor, and anhydrous ammonia), time of application (spring, fall) and method of application (broadcast, banded) on nitrous oxide emissions on two Black Chernozemic soils located near Winnipeg and Brandon Manitoba. The results of this 3-yr study demonstrated consistently that the rate of fertilizer-induced N2O emissions under Manitoba conditions was lower than the emissions estimated using Intergovernmental Panel on Climate Change (IPCC) coefficients. The Winnipeg site tended to have higher overall N2O emissions (1.7 kg N ha-1) and fertilizer-induced emissions (~0.8% of applied N) than did the Brandon site (0.5 kg N ha-1), representing ~0.2% of applied N. N2O emissions in the first year of the study were much higher than in subsequent years. Both the site and year effects likely reflected differences in annual precipitation. The N2O emissions associated with the use of anhydrous ammonia as a fertilizer source were no greater than emissions with urea. Fall application of nitrogen fertilizer tended to result in marginally greater N2O emissions than did spring application, but these differences were neither large nor consistent. Key words: Nitrogen fertilizer, nitrous oxide emissions, nitrate intensity, anhydrous ammonia, urea
Autotrophic and heterotrophic respiration rates across a chronosequence of hybrid poplar plantationsin northern Alberta
Authors: Saurette Daniel D , Chang Scott X , Thomas Barb R
Published: April 2011

Distinction of autotrophic (root, Rr) versus heterotrophic (Rh) soil respiration is important to understanding C balance in forest ecosystems and the contribution of both respiration components to total soil respiration (Rs) may change as stands mature. We studied Rr and Rh in a chronosequence of hybrid poplar plantations that were 4, 6, 8, and 13 yr old in summer 2005. We hypothesized that Rr will become increasingly larger and will also represent a greater proportion of Rs as plantation age increases. Our results showed that both Rs and Rh showed significant seasonal variations; however,Rr were much more variable. No significant differences among plantation ages were observed for any of the respiration parameters (Rr, Rh and Rs) measured throughout the summer. No significant differences were found for the contribution of Rh to Rs between plantation ages or between sampling dates. The average proportion of Rh to Rs across all sites and sampling dates was 0.63 ± 0.026 (mean ± standard error), indicating that heterotrophic respiration dominated total soil respiration in the studied hybrid poplar plantations.The power of the statistical tests in this study was likely quite low due to the inclusion of only two replicates for each plantation age. Key words: Autotrophic, heterotrophic respiration, root exclusion, trenching, hybrid poplar, chronosequence
Influence of biosolids on phosphorus sorption characteristics of a Vertisol in comparison with manures and fertilizer
Authors: Ajiboye Babasola , Akinremi Olalekan O , Racz Geza J , Flaten Donald N
Published: April 2011

Regulation of manure application in Manitoba has raised the question of whether or not biosolids application should be regulated in the same way. This study examined the effects of biosolids (BIO) applications on P sorption characteristics of a Vertisol in comparison with dairy cattle (DAIRY) and hog (HOG) manures, and monoammonium phosphate (MAP) fertilizer using the classical sorption isotherm and single point sorption index. Pertinent chemical properties and degree of P saturation (DPS) were also determined. The sorption maximum (Smax) in the control was reduced from 655 mg kg-1, to a range of 536–655 mg kg-1 with BIO, 559–650 mg kg-1 with MAP, 402–568 mg kg-1 with DAIRY, and 350–587 mg kg-1 with HOG depending upon the rate of P added. The lower DPS in the soil amended with BIO suggests a lower risk of P loss with biosolids compared with manures. The higher P sorption capacity of biosolids-amended soils compared with soils amended with manures suggest that Ca added with BIO increased the number of P sorption sites by a similar proportion to the amount of P added. Key words: Biosolids, P sorption isotherm, degree of P saturation, labile P, non-labile P
Assessing organic potato cropping systems at the end of the first cycle of four-year rotations using principal component analysis
Authors: Liu K. , Hammermeister A M , Patriquin D G , Martin R C
Published: April 2011

A single or a few variables may not be sufficient to evaluate management practice effects in a complicated cropping system, so six plant and 13 soil variables were integrated using principal component analysis (PCA) to examine nine 4-yr organic potato rotations. The rotations were combinations of three forage levels (0, 1, and 2 yr of forages) with three soil amendments (monogastric compost, ruminant compost, and alfalfa meal). Quantities of amendments were estimated by soil test recommendations and amendment nutrient availabilities. In the 4th potato year, one half of each original plot was not amended ("the 4th year unamended plots"), while the other half received soil amendments ("4th year amended plots"). The first three principal components explained 67 and 63% of the overall variation for the 4th-yr amended and unamended plots, respectively. PCA ordination plots indicated that, overall, the type of soil amendments had larger effects on soil and plant variables, but forage frequencies were influential for the amendments showing weaker effects. PCA loading plots indicated that plant nutrient uptake and potato total tuber weight would be the best single variables for characterizing the current cropping systems. Plant variables, except for potato petiole nitrate, were closely displayed, but they were not strongly correlated with soil variables, which may reflect the high background fertility of this site. Applications of soil amendments in the 4th yr affected the relationships among variables, most notably the strength of relationships between soil pH and soil N variables. The results suggest that PCA provides an effective way to compare complex cropping systems, especially in situations with high site heterogeneity. Key words: Principal component analysis, soil amendment, livestock system, forage, potato, organic crop rotation
Surface runoff response of native and introduced grasses under simulated rainfall in southern Alberta
Authors: Murphy Sean R , Larney Francis J , Willms Walter D , DeMaere Paul R
Published: April 2011

Introduced perennial grass-based pastures (e.g., crested wheatgrass, Agropyron cristatum, and Russian wildrye, Elymus junceus) are promoted as desirable alternatives to natural grasslands (Stipa-Bouteloua-Agropyron spp.) for livestock production systems on the mixed-grass prairie of Alberta. A study was conducted on plots established in 1993 to examine the surface runoff response from natural grasslands, introduced grasses and spring wheat (Triticum aestivum L.) under simulated rainfall in response to pasture and soil characteristics. The grass plots were never grazed, but herbage growth was harvested on an annual basis, while wheat was seeded each year following tillage. Both wheat and crested wheatgrass were less able to retain applied water; with low initial abstraction (5.1–5.7mm), runoff peaked earlier (14–26 min) and with higher intensity (65.1–68.8mm h-1) giving larger values of the rising limb factor (0.61–1.10). Two grasslands dominated by native species showed more desirable runoff characteristics; with high initial abstraction (9.6–13.3mm), runoff peaked later (32–54 min) and with lower intensity (32.7–45.8mm h-1) giving smaller values of the rising limb factor (0.13–0.35). Russian wildrye had an intermediary response. A linear model identified that to reduce the rising limb factor and amount of runoff generated after 30 min, the antecedent conditions of ground cover (%), litter dry matter (DM) and dead herbage DM were singularly important variables and the native grasslands had significantly higher levels of these. Importantly, fine and medium litter fragments of natural grasslands had higher water-holding capacity (>3.0 g g-1) compared with litter of the introduced species (~2.5 g g-1). However, when variables were considered in combination runoff decreased with higher ground cover and increased with higher soil water content. Levels of total N and total P in surface runoff were generally low (< 2 mg N L-1, < 1 mg P L-1), but ammonium and reactive P export from the native species was greater than for the introduced species. Suspended sediment yield did not differ among the grassland treatments, but was significantly higher for wheat. Less runoff was generated on grasslands that had high amounts of litter, dead standing herbage and ground cover. Increasing the amount of litter in pastures by using grazing management may decrease the runoff response and so avoid loss of surface water and soil nutrients. Key words: Ground cover, litter, water quality, native grasses, nutrients
A review of the effects of long-term 2,4-D and MCPA applications on wheat production and selected biochemical properties of a Black Chernozem
Authors: Smith A. E. , Hume L. , LaFond G. P. , Biederbeck V. O.
Published: April 2011

Rotational plots at the Agriculture Canada Experimental Farm at Indian Head, Saskatchewan, have been receiving annual applications of amine and ester formulations of 2,4-D since 1947, and MCPA amine since 1953. These research plots are unique world-wide for the length of time of application of these herbicides. Wheat yield data from 1973 to 1989 indicate that the continuous use of the herbicides significantly increased yields compared to untreated control plots. In both 2,4-D and MCPA treatments, susceptible weeds were greatly reduced, but not eliminated. No new major weed species became established. After 35 yr of 2,4-D application there were no ecologically significant effects on selected soil biochemical processes, nor had the herbicides interfered with the normal cycling of carbon, nitrogen, or phosphorus. Following 33 yr of MCPA treatments there were, except for yeasts, no significant changes in microbial biomass or microbial populations. After 40 successive treatments of 2,4-D amine and ester, and 35 annual applications of MCPA, herbicide residues in the 0- to 15-cm and 15- to 30-cm soil depths were less than detectable limits of < 0.03 kg acid ha−1. Under laboratory conditions, the breakdown of added 2,4-D and MCPA was faster in soils receiving continuous herbicide applications than in soil from untreated control plots, suggesting that some soil microbiological adaptation had occurred. It can be concluded that there have been no adverse effects on crop productivity of the soil from the long-term use of 2,4-D and MCPA. Key words: Phenoxies, continuous use, wheat production, weed populations, soil biochemical activities, microbial degradation
Détermination au champ de la conductivité hydraulique saturée à l'aide de l'infiltromètre à charge constante de Côté: théorie et approximations mathématiques
Authors: Banton O. , Côté D. , Trudelle M.
Published: April 2011

Saturated hydraulic conductivity is one of the most difficult physical parameters of soil to measure. The most accurate methods are those used in the field in the presence of a groundwater table. However, in many cases, these cannot be used, primarily when no groundwater table is present. The Côté constant head infiltrometer method proves useful in such cases, because the measurement is made on soil which is not necessarily saturated beforehand. The constant head of water used by the infiltrometer is low (3.5 cm), and so representative of precipitation and irrigation conditions. The device (which is 10 cm in diameter) performs the measurement on a large area of soil (roughly 200 cm2), and can therefore integrate varying heterogeneity and macroporosity, rendering the measurement more reliable and representative. The quantity of water needed for a measurement is about 1 L, making operation in the field easier. The Côté constant head infiltrometer is an unsophisticated device which is easy to use. Different mathematical approximations of the saturated flow of water around the infiltometer are described according to the various forms of flow taken into account. The corresponding coefficients may be used to quickly determine this parameter with a high level of confidence. However, one problem and some potential sources of error remain in the evaluation of hydraulic conductivity in the field, due principally to cases in which the soil is not totally saturated, to compaction or smoothing of the hole during digging, and to the variability of the parameter on the site. Key words: Hydraulic conductivity, infiltrometer, permeameter
Intercropping red clover with silage corn for soil erosion control
Authors: Wall G. J. , Pringle E. A. , Sheard R. W.
Published: April 2011

A red clover intercrop was evaluated in terms of its ability to provide soil erosion protection and its effects on silage corn yields on a Conestoga loam soil at the Elora Research Station, Elora, Ontario. The soil and runoff losses from experimental plots of silage corn (corn system) and silage corn intercropped with red clover (corn/clover system) were compared using the Guelph Rainfall Simulator II. Measurements were made in November 1987 and October 1988, and in April, May, June of 1988 and 1989. Rainfall was applied for 10 min (15 min in June of 1988) on a 1-m2 quadrat at an intensity of 16 cm h−1. Soil loss was significantly (P < 0.05) lower from the corn/clover cropping system than the corn system for all months except June 1989. Runoff reduction with the corn/clover system ranged from 45 to 87%, with largest reductions occurring in June. Reduction of soil loss from the corn/clover system as compared to the corn system ranged from 46 to 78%. Silage corn yield data from 1984 to 1989 illustrated that, where no additional N was added, yields from the corn/clover system consistently exceeded yields from the corn system. Where N was added, continuous corn yields were only slightly greater than those from the corn/clover system. It is concluded that intercropping silage corn with red clover can provide soil erosion protection without significant effect on silage corn yields. Key words: Runoff, erosion, rainfall simulation, residue
Degradation of waste 2,4-D residues using a soil bacterium in a sprayer tank system
Authors: Smith A. E. , Mortensen K.
Published: April 2011

A soil bacterium has been isolated from field soils receiving annual applications of 2,4-D and tentatively identified as Pseudomonas testosteroni Marcus and Talalay. When added to a sprayer tank containing an aerated solution of simple mineral salts and 2,4-D amine formulations, this organism used the herbicide as a carbon source, with stoichiometric release of chloride. This system has been used to biologically degrade 2,4-D amine residues from farm operations and herbicide containers. Key words: Degradation, bacterium, residues, soil, 2,4-D
Fiabilité d'une étude pédologique détaillée réalisée en terrain plat
Authors: Nolin M. C. , Lamontagne L.
Published: April 2011

In order to estimate the reliability of soil information presented in a detailed soil survey (1:20 000 scale) conducted in a flat terrain (Vercheres county, Quebec), 35 randomly selected delineations were inspected with 10 sites per delineation. Reliability was evaluated according to parent material (marine, estuarine and fluvial) and kind of map units (simple and compound). As a whole, mineral soils have been mapped and defined reliably for most criteria commonly used in soil interpretation systems. Reliability of soil information differed significatively with parent material. Taxonomic purity of marine, fluvial and estuarine soils delineations were 70, 58 and 28%, respectively. Although less precise, compound map units were more reliable than simple map units. Among the 13 soil variables studied, A and B horizons texture, B horizon designation and depth to carbonates were the more frequently in error. Results finally indicated that reliability is also a function of the delineation area and inspection density. In order to improve reliability of soil information and accelerate soil survey in future projects, it is suggested to adjust inspection density according to parent material, to reduce the number of classes for a few variables and to avoid excessive use of soil series'variants and delineations of small size (< 4 ha). Key words: Reliability, purity, accuracy, soil survey procedures, inspection density
The effect of pedogenetic processes on the distribution of phosphorus, calcium and magnesium in Gray Luvisols
Authors: Xiao X. J. , Anderson D. W. , Bettany J. R.
Published: April 2011

Pedogenesis and its effect on calcium (Ca), magnesium (Mg) and phosphorus (P) was studied on a sequence of seven Gray Luvisol soils in central Saskatchewan. The soils were formed on calcareous glacial till under trembling aspen (Populus tremuloides Michx), mixedwood (aspen and white spruce) (Picea glauca (Moench) Voss)) and coniferous (black spruce and jack pine) (Picea mariana (Mill) BSP and Pinus banksiana Lamb) forests. Soils under aspen had the highest concentration of total and exchangeable Ca and Mg in litter layers and Ae horizons, and had Ae and Bt horizons that were least acidic. The most acidic Ae and Bt horizons and lowest amounts of Ca and Mg occurred under coniferous forests, whereas the soils under mixedwood stands were intermediate. The thickness of eluvial (Ae and AB) horizons increased along the aspen to coniferous sequence. All soils had about 40% less P in their A and B horizons than was calculated to have been present at the start of soil formation. The greatest decrease in P was observed in the thickest and most acidic soil under coniferous forest. The present litter layers and vegetation make up only a small proportion of the P removed from the mineral soil. Unusually large amounts of P appear to have been translocated from A and B horizons during development of Gray Luvisols, in comparison to Chernozemic or even Podzolic soils. Our hypothesis proposes that P is ineffectively retained in the solum as P-clay-humus, or iron-P complexes and that organic P moves along with the soil water, laterally and downslope through permeable Ae horizon over less permeable Bt horizons, or vertically through macropores. Key words: Boreal forest, nutrient cycling, phosphorus losses, weathering, soil formation