bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutritive value of an extruded blend of canola seed and pea (Enermax™) for poultry
Authors: Golian A. , Campbell L. D. , Nyachoti C. M. , Janmohammadi H. , Davidson J. A.
Published: April 2011

A study was conducted to evaluate the nutritive value of Enermax™, which is a blend (50:50 wt/wt) of extruded full- fat canola seed and pea. Four blended samples from each of four batches were collected prior to extrusion (raw) and four samples from the same batches were collected after extrusion to give eight test samples. The canola seed in two of four batches were of good quality and in the other two were 8% bin-heated. The precision-fed adult rooster assay was used to determine the true metabolisable energy (TMEn) and true amino acid digestibility (TAAD) contents of variously treated feed samples. Both intact and cecectomized roosters were used in the assays. The average TMEn (kcal kg-1 DM) of the extruded product was 4051 ± 93 (mean ± SD; n = 16) for intact birds and 4019 ± 110 (n = 16) for cecectomized birds whereas the TMEn of the raw product was 3754 ± 136 (n = 16 ) in cecectomized birds. The true digestibilities of all amino acids were similar for extruded and raw product of canola seed-pea blend containing either good quality or 8% bin-heated canola seed (P > 0.10). These data indicate a high available energy content of the extruded product with little difference in TMEn content when measured using either intact or cecectomized roosters. It was concluded that extrusion improved the bio-available energy content of the canola seed-pea product, but not true amino acid digestibility. Further, the current results indicate that substitution of bin-heated (8%) canola seed for good quality canola seed did not adversely affect TMEn or TAAD of the extruded product. Key words: Poultry, nutritive value, extruded canola seed-pea blend
Review: Energy partitioning in broiler chickens
Authors: Lopez G. , Leeson S.
Published: April 2011

In commercial nutrition and in research studies, metabolizable energy (ME) is the standard measure of energy used in describing energy requirements and diets for poultry. The provision of dietary energy will influence the intake of all other nutrients. Broilers exhibit an outstanding ability to control their energy intake by adjusting their feed intake as diet energy concentration changes. There is still considerable debate on the accuracy, precision and usefulness of different procedures used for determining ME values of diets and ingredients. ME intake is generally partitioned into energy retained (ER) in body tissues (mainly as fat and protein) and as heat production (HP): ME = HP + ER. There are few reported estimates of HP and its components, fasting heat production (FHP), heat production due to physical activity and the thermic effect of feeding (TEF). Requirements for maintenance (MEm), including major components of FHP and physical activity, are established at around 155 kcal kg BW0.60. We recentlyreported that maintenance requirements for young broilers based on kg BW0.75 were 8% lower than the values estimated using kg BW0.60, and that BW raised to the exponent 0.60, was a more precise estimator. Gross energy retained in the body as fat (TERF) and protein (TERP), together contribute most of the total energy retained (TER) in the body. Efficiency of ME utilization above maintenance varies from 70 to 84% for lipid deposition in adult birds and between 37 and 85% in growing birds. Key words: Energy, broiler, metabolic rate, energy retention
Forage yield performance and nutritive value of selected wild soybean ecotypes
Authors: Zhai Guiyu , Shen Yixin , Zhai Yujia , Liu Xinbao , Jiang Huixin
Published: April 2011

Field experiments were conducted to evaluate the yield, yield components and quality of three wild soybean (Glycine soja Sieb. and Zucc.) ecotypes (FJW-9, SDW-12 and HLW-18) as forage in Dongying Forage Experiment Station of China in 2004 and 2005. Biomass yield and nutritional quality were observed using leaf, stem and whole plant taken from five harvest dates. The results show that the harvest dates had significant effects on leaf, stem, pod and whole-plant dry matter yields and forage quality (P < 0.01). Wild soybean ecotypes included in the study produced whole-plant drymatter from 2.3 to 6.5 Mg ha-1 at different harvest dates. The highest dry matter yield came from the Sep. 17 harvest date, with average crude protein (CP) concentration of 191 g kg-1, neutral detergent fiber (NDF) concentration of 355 g kg-1 and acid detergent fiber (ADF) concentration of 254 g kg-1. Ecotype FJW-9 had higher dry matter yields of leaf, stem and whole plant than SDW-12 and HLW-18 (P < 0.05). Mean CP concentration in whole plant of FJW-9 was higher (212 g kg-1) compared with the other two ecotypes (205 and 199 g kg-1), while the mean NDF and ADF concentrations of FJW-9 were lower than HLW-18 and SDW-12. Dry matter partitioning of wild soybean plant parts was greatly affected by harvest dates. There were statistically significant differences between wild soybean ecotypes in leaf, stem and whole-plant yields. The correlation between whole-plant dry matter yield and pod yield was not statistically significant (r = 0.13). These results suggest that wild soybeans have the potential to provide forage of high quality and adequate quantity for animals. Key words: Wild soybean, yield, nutritive value
Light interception and radiation use efficiency of fern- and unifoliate-leaf chickpea cultivars
Authors: Li Lin , Bueckert Rosalind A , Gan Yantai , Warkentin Tom
Published: April 2011

A chickpea (Cicer arietinum L.) crop with rapid leaf development, high solar radiation interception, and efficient use of radiation can maximize the yield potential in a short-season typical of the Northern Great Plains. This study determined the effects of cultivars varying in leaf architecture on light interception (LI) and radiation use efficiency (RUE) in chickpea. Six kabuli chickpea cultivars with fern and unifoliate-leaf traits were grown under low (45 plants m-2) and high (85 plants m-2) population density at Saskatoon and Swift Current, Saskatchewan, in 2003 and 2004. Fern-leaf cultivars achieved consistently higher maximum LI, and greater cumulative intercepted radiation than cultivars with the unifoliate-leaf. Estimated RUE varied largely with growing season, but did not differ among cultivars or between plant populations. Compared with low plant population, high plant population resulted in greater maximum LI in only 1 out of 4 location-years, but higher cumulative intercepted radiation in 3 out of 4 location-years. Our results indicated that future high-yielding kabuli chickpea cultivars for short seasons will benefit from increased canopy LI and seasonal cumulative intercepted radiation via the fern-leaf trait, although the fern-leaf does not further increase RUE. Use of fern-leaf cultivars, coupled with adoption of strategies that promote a rapid canopy development and improved radiation interception are keys to maximizing chickpea yield potential in the short-seasons experienced in the Northern Great Plains. Key words: Cicer arietinum, pinnate fern-leaf, unifoliate, plant population, canopy, radiation interception
Effect of long-term burn-pruning on the flora in a lowbush blueberry (Vaccinium angustifolium Ait.) stand
Authors: Penney B. G. , McRae K. B. , Rayment A. F.
Published: April 2011

The effect of burn-pruning on the flora in a natural stand of lowbush b lueberry was studied over a 24-yr period in Newfoundland and Labrador, Canada. Treatments were: not burned and burn-pruned every 2nd, 3rd, or 4th year. A vegetative survey was conducted before burning and periodically in succeeding years. Following statistical analyses, species were grouped according to their response to burning, as follows: those not significantly affected; those eliminated or whose frequency of occurrence was reduced; and those whose occurrence was increased. Initially, burning virtually eliminated Juniperus communis var. depressa, Empetrum nigrum, Cladina rangiferina, Lycopodium clavatum and Pleurozium schreberi, reduced the frequency of occurrence of nine species by 6 to 69%, and increased 13 others by 1 to 2050%. With burning, Polytrichum commune and Fragaria virginiana ssp. glauca, in particular, increased very early in the study to become two of the most prevalent species. Also, except for some initial effects of burning, the lowbush blueberry and some initially prevalent species (Festuca filiformis, Maianthemum canadense, Danthonia spicata, Cornus canadensis and Luzula multiflora var. acadiensis) remained among the most dominant species. Of the species studied, only seven each of those increased or decreased by burning were affected by the burn-pruning cycle. In both groups, the greatest increases or decreases in the frequency of occurrence were obtained with the 2-yr burn-pruning cycle. Key words: Lowbush blueberry, Vaccinium angustifolium, burning, pruning, plant succession, weeds, fire, flora
The biology and ecology of hexaploid wheat (Triticum aestivum L.) and its implications for trait confinement
Authors: Willenborg C. J. , Van Acker R. C.
Published: April 2011

This review summarizes the biological and ecological factors of hexaploid wheat (Triticum aestivum L.) that contribute to trait movement including the ability to volunteer, germination and establishment characteristics, breeding system, pollen movement, and hybridization potential. Although wheat has a short-lived seedbank with a wide range of temperature and moisture requirements for germination and no evidence of secondary dormancy, volunteer wheat populations are increasing in relative abundance and some level of seed persistence in the soil has been observed. Hexaploid wheat is predominantly self-pollinating with cleistogamous flowers and pollen viability under optimal conditions of only 0.5 h, yet observations indicate that pollen-mediated gene flow can and will occur at distances up to 3 km and is highly dependent on prevailing wind patterns. Hybridization with wild relatives such as A. cylindrica Host., Secale cereale L., and Triticum turgidum L. is a serious concern in regions where these species grow in field margins and unmanaged lands, regardless of which genome the transgene is located on. More research is needed to determine the long-term population dynamics of volunteer wheat populations before conclusions can be drawn with regard to their role in trait movement. Seed movement has the potential to create adventitious presence (AP) on a larger scale than pollen, and studies tracing the movement of wheat seed in the grain handling system are needed. Finally, the development of mechanistic models that predict landscape-level trait movement are required to identify transgene escape routes and critical points for gene containment in various cropping systems. Key words: Triticum, coexistence, gene flow, genetically-engineered, herbicide-resistant, trait confinement
Alvena hard red spring wheat
Authors: Knox R. E. , DePauw R. M. , Clarke F. R. , Clarke F. R. , McCaig T. N. , Fernandez M. R.
Published: April 2011

Based on 38 replicated trials over 3 yr, Alvena, hard red spring wheat (Triticum aestivum L.) expressed significantly higher mean grain yield than the checks. It was significantly earlier maturing than AC Barrie and significantly more resistant to lodging than Katepwa. Wheat protein concentration of Alvena was similar to the mean of the checks and flour protein concentration was significantly higher than the check mean. Amylograph viscosity was significantly lower than the mean of the checks. Alvena meets the end-use quality and Canadian Grain Commission’s kernel visual distinguishability specifications of the Canada Western Red Spring wheat market class. Alvena expressed moderate resistance to prevalent races of loose smut and stem rust, intermediate resistance to prevalent races of leaf rust and common bunt, and moderate susceptibility to fusarium head blight. Key words: Triticum aestivum L., cultivar description, grain yield, maturity, disease resistance
Tapani red clover
Authors: Papadopoulos Y. A. , Christie B. R. , Choo T. M. , Michaud R. , McRae K. B. , Gehl D. , Fillmore S. A. E.
Published: April 2011

Tapani is a 21-clone diploid synthetic cultivar of red clover (Trifolium pratense L.). It was developed by phenotypic selection at Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, in Charlottetown, Prince Edward Island, and at the Soils and Crops Research and Development Centre in Quebec City, Quebec. The original material for this strain was selected from collections made in old stands of red clover in three Atlantic Provinces of Canada. Tapani is early flowering and winterhardy. In Atlantic Canada, Tapani yielded an average of 109% of the check cultivar Marino over three production years. This cultivar has superior re-growth potential with high second-cut herbage yield. Key words: Red clover, Trifolium pratense L., cultivar description
Near-infrared versus visual sorting of Fusarium-damaged kernels in winter wheat
Authors: Wegulo Stephen N , Dowell Floyd E
Published: April 2011

Fusarium head blight (scab) of wheat, caused by Fusarium graminearum, often results in shriveled and/or discolored kernels, which are referred to as Fusarium-damaged kernels (FDK). FDK is a major grain grading factor and therefore is routinely determined for purposes of quality assurance. Measurement of FDK is usually done visually. Visual sorting can be laborious and is subject to inconsistencies resulting from variability in intra-rater repeatability and/or inter-rater reliability. The ability of a single-kernel near-infrared (SKNIR) system to detect FDK was evaluated by comparing FDK sorted by the system to FDK sorted visually. Visual sorting was strongly correlated with sorting by the SKNIR system (0.89 ≤ r ≤ 0.91); however, the SKNIR system had a wider range of FDK detection and was more consistent. Compared with the SKNIR system, visual raters overestimated FDK in samples with a low percentage of Fusarium-damaged grain and underestimated FDK in samples with a high percentage of Fusarium-damaged grain. Key words: Wheat, Fusarium head blight, Fusarium-damaged kernels, single-kernel near-infrared
Timothy mineral concentration and derived indices related to cattle metabolic disorders: A review
Authors: Pelletier Sophie , Bélanger Gilles , Tremblay Gaëtan F , Virkajärvi Perttu , Allard Guy
Published: April 2011

Timothy (Phleum pratense L.) is grown in several countries, mainly for livestock forage. The nutritive value and dry matter (DM) yield of timothy is well established but less information is available on mineral concentration and related indices, like the dietary cation-anion difference (DCAD) and the grass tetany (GT) index. These indices predict the risk of a forage diet to cause metabolic disorders, i.e., milk fever for DCAD and grass tetany for the GT index. Improving our knowledge of factors affecting timothy mineral concentration is important for livestock production. This review paper compares timothy with other common cool-season grasses for mineral concentrations, DCAD, and GT index. Also assessed are variations in timothy mineral concentration affected by harvest and fertilization management, soil mineral availability, and environmental conditions. These results demonstrate the high potential for improvement and use of timothy forage to decrease the incidence of metabolic disorders within the dairy industry. Key words: Milk fever, grass tetany, dietary cation-anion difference, grass tetany index, forage, cool-season grasses
Revisiting seedrow nitrogen placement with barley and wheat
Authors: Karamanos R. E. , Harapiak J. T. , Flore N. A.
Published: April 2011

The rates of nitrogen (N) that can be safely placed with the seed remains a frequent question of producers, especially as direct seeding continues to increase as a practice in western Canada. Guidelines have been in place since the mid-1990s; however, they address only "favourable conditions" and experimentation relating to their derivation has not been formally published. This study attempted to quantify "favourable conditions" as well as supplement existing guidelines with information under non-favourable or ideal conditions so that producers may assess the risk of applying N with the seed. To this end, the results from 32 experiments with CWRS wheat and 10 with barley conducted in early to mid-1990s were compiled. The experimental design included three seedbed utilization (SBU) rates (10, 20, and 40%) and five N rates (0, 20, 40, 60, and 80 kg N ha-1) with four replications. Grain yield, relative plant stands (calculated as a percentage of the unfertilized control) and days to maturity (DTM) were determined in all experiments. Three types of responses to seedrow N application occurred. Type A had no impact of fertilizer N rate on the yield of CWRS wheat at wide (40%) SBU, but grain yield decreased at narrower SBU (10 and 20%). Type B had no impact of fertilizer N rate on the yield of CWRS wheat at narrow (10%) SBU but grain yield increased at wide SBU (20 and 40%). Type C had grain yield increases due to fertilizer N independent of SBU. Type A was characterized by dry soil moisture conditions and relatively high residual NO3−-N levels, whereas Types B and C were characterized by normal and very moist soil conditions and low to medium residual NO3−-N levels. The results within each response type were modified by soil organic matter (SOM) and texture. Grain yield losses generally occurred when relative plants stands were below 85% of those of unfertilized plots. In addition, conditions that led to a decrease in relative plant stands and grain yield also resulted in delayed maturity. Accounting for all the above factors enabled us to expand current guidelines under normal conditions to a range of agroecological conditions. Key words: Guideline, texture, soil organic matter, residual NO3−-N, soil moisture
CDC Patrick field pea
Authors: Warkentin Tom , Vandenberg Albert , Tar’an Bunyamin , Banniza Sabine , Bett Kirstin , Barlow Brent , Ife Scott
Published: April 2011

CDC Patrick, a green 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 Patrick has a semileafless leaf type, good lodging resistance, powdery mildew resistance, medium-sized seeds with round shape, good cotyledon bleaching resistance and good yielding ability. CDC Patrick is adapted to the field pea growing regions of western Canada. Key words: Field pea, Pisum sativum L., cultivar description
Upslope length improves spatial estimation of soil organic carbon content
Authors: Luca Carol , Si Bing C , Farrell Richard E
Published: April 2011

Quantifying soil organic carbon (SOC) is important to aide in assessing carbon (C) sequestration potential, and as an indicator of soil quality. However, intensive s ampling of SOC for quantification can be expensive and time consuming. The objectives of this study were to identify which topographic index correlated best with SOC and determine if incorporating the index improved interpolation of limited SOC data. A transect with 93 sample points spaced 6 m apart was set up, and four topographical indices (curvature, wetness index, upslope length, and elevation) were evaluated for their potential as secondary variables. Three Kriging-based interpolation methods, ordinary kriging, cokriging, and simple kriging with varying local means were compared to determine if incorporating topographical indices improved interpolation of SOC. The upslope length, which takes into consideration the quantity of water that will be redistributed to a point, was found to have the strongest relationship with SOC (R2 = 0.48, P < 0.01) and was used as a secondary variable for kriging. Thirty points from the SOC data were randomly selected and used in the kriging algorithms to estimate the remain ing 63 points. The sum of squared differences (SSD) showed a significant reduction (from 1677 to 1455 for SKlm and from 1677 to 1464 for cokriging) in estimates when upslope length was used as a secondary variable. These results indicate that fewer samples may be taken to estimate SOC accurately and precisely if upslope length is incorporated. On a landscape scale this could facilitate quantification of carbon credits and management decisions in precision farming systems. Key words: Geostatics, kriging, cokriging, organic carbon, landscape processes, wetness index
Effect of a lignite-coal extract on nutrient composition and gas emissions from cattle feedlot manure
Authors: Hao Xiying , McAllister Tim , Wang Yuxi
Published: April 2011

An experiment was conducted to determine the effect of a liquid lignite coal extract (LC; pH = 3.5) on gas emissions and the chemical composition of feedlot cattle manure. Eighty steers were randomly divided into four groups, penned individually, and fed a barley grain – barley silage diet sprayed with 0 (control), 0.5, 1.0 or 2.0 L of LC per tonne of dry matter. Manure samples (mixture of excreta and wood chips) were collected 25, 53, 81, 109 and 150 d after the LC was included in the diet. Inclusion of LC in the diet reduced both the pH and dissolved NH3+ NH4+ content of manure collected on days 25 and 53. Ammonia emissions were also significantly reduced on these occasions. In addition, butyric acid content was higher and isovaleric acid content lower in manure from cattle fed LC compared with manure from control cattle. Levels of nitrate, total volatile fatty acid (VFA), acetic, isobutyric, propionic, and capric acid in manure were not altered by the inclusion of LC in the diet. Greenhouse gas emissions (CO2, CH4 and N2O) from manure were not affected by inclusion of LC in the diet. The lower manure pH, NH3 + NH4+ content and NH3 emission at early sampling dates suggest that LC could play a role in reducing gaseous ammonia N emission to the atmosphere. Further studies are needed to determine whether the reduction in dissolved NH3 + NH4+ content in manure is due to an LC-mediated change in the amount of urea produced by the animals or to the inhibition of the hydrolysis of urea in manure. Key words: Cattle (feedlot), urea (manure properties), VFA content, greenhouse gas (CH4, N2O, CO2), emission, ammonia emission
Long-term influence of compost on available water capacity of a fine sandy loam in a potato rotation
Authors: Carter M R
Published: April 2011

An improved soil physical structure, associated with organic amendments in crop rotations, can be viewed as an emergent property. A study was conducted to evaluate the effect of applied compost on soil water retention and available water capacity, and other associative soil properties in a long-term 3-yr potato rotation established on a Charlottetown fine sandy loam (Orthic Humo-Ferric Podzol) in Prince Edward Island. Soil samples (0–10 cm) were obtained from two crop phases (barley and potato) during the fourth cycle of the rotation (after four compost applications) in the 12th year of the experiment. Except for particulate N, compost had little effect on soil organic matter. In comparison to the barley phase, a combination of compost and surface tillage in the potato phase was associated with improved soil porosity parameters and increased soil water contents at −33 kPa (“field capacity” ), −100 and −300 kPa matric potential, compared with the no-compost control. These results indicate that compost stabilized the tillage induced soil aggregates and macro-porosity in the potato phase. Regression analysis showed that soil volumetric water content at both −33 and −1500 kPa matric potential was significantly related to soil C concentration, although the soil available water capacity remained unchanged. The results imply that the “non-nutrient” compost effect on potato productivity was related to soil water retention. Key words: Soil water retention, soil physical and biochemical properties, compost amendment, tillage, potato rotation, eastern Canada
Assessing spatial distribution and joint uncertainty of TPH-fractions: Indicator kriging and sequential indicator simulation
Authors: Luca Carol , Si Bing C , Farrell Richard E
Published: April 2011

Petroleum hydrocarbon (PHC) contamination is one of the most common contaminants in soils and remediation of PHC-contaminated sites requires methods for characterizing the spatial distribution of PHC on a site. Few studies have compared the performance of indicator kriging (IK) and sequential indicator simulation (SIS) in site characterization of petroleum-contaminated sites, or the application of these methods given the fraction based guidelines. The objectives of this study were to determine if IK and SIS indicate similar contaminated areas and to examine how the probability of exceeding thresholds changes when multiple fractions are considered simultaneously. An abandoned refinery near Kamsack, Saskatchewan, characterized by clay-textured soils was sampled and analyzed for PHC fractions (F2 and F3). The probability of a location exceeding a fraction’s remediation criteria was determined using IK and SIS. Based on critical probability thresholds, IK indicated a greater area was contaminated by F2 (6.3%) and F3 (0.8%) than SIS (4.5 and 0.6%, respectively). When the remediation criteria for both F2 and F3 were considered simultaneously, “dependent” and “independent” cases were examined. The dependent case assumed perfect correlation and used the maximum probability of either F2 or F3 as the new estimate. The independent case assumed no correlation and evaluated the probability of F2 > 2500 mg kg–1 or F3 > 6600 mg kg–1. The dependent case resulted in a smaller contaminated area than the independent case in both IK and SIS. On this site the differences between the two methods were small, although IK did smooth the distribution. Key words: Sequential indicator simulation, indicator kriging, geostatics, petroleum hydrocarbon contamination, uncertainty
Selection and establishment of Alberta agricultural soil quality benchmark sites
Authors: Cathcart Jason , Cannon Karen , Heinz Jody
Published: April 2011

Forty-three benchmark sites were established to monitor soils across the agricultural regions of Alberta. Soil chemical and physical properties were examined in an initial pedological investigation in 1997. This paper describes site selection and presents results from the initial pedological investigation. Ninety-five percent of the chosen sites were representative of their provincial ecodistrict, with only two profiles being darker and higher in organic carbon than expected. The majority of selected sites were gently undulating loam soils on morainal parent materials in the dryland regions of Alberta. Soil texture, cation exchange capacity, calcium carbonate content, and soil pH reflected regional differences in quaternary geology and agricultural practices across Alberta. Southern Alberta was characterized by high pH, sandier-textured soil profiles, whereas the Peace Lowlands, being derived from marine shale deposits, exhibited finer soil textures and higher cation exchanges capacities. Owing to climatic and vegetative differences, organic carbon levels were significantly greater in northern Alberta compared with the south, but were found to differ based on soil horizon and slope position. Upper slopes typically had lower organic carbon levels, particularly in the A horizon. Similar results were observed for total soil N, although other soil nutrients differed in relation to soil properties, slope and ecoregion. Data collected will provide: (a) the basis for a detailed Alberta soil quality assessment, (b) data for future modeling efforts, and (c) data necessary to identify temporal changes in soil properties, yield and management relationships. Key words: Agronomic practices, catena, ecodistrict, pedological investigation, soil landscape, soil quality
Determination of solute leaching potential within a hummocky agricultural landscape
Authors: Thibodeau J. , Fuller L G , Chanasyk D S
Published: April 2011

Leaching of water-soluble contaminants has resulted in degradation of groundwater quality. This research project examined the long-term spatial variability of leaching processes within two hummocky, agricultural landscapes near Bittern Lake, in central Alberta. Analysing the distribution of soil profiles within a landscape, we created a leaching potential index based on a soil profile index (SPI) and plan curvature measurements. The index accurately differentiated locations of very high and high leaching potential from low and very low leaching potential. This index may become a useful tool to determine the variability of leaching within an agricultural landscape, to identify areas of high leaching potential, to determine agricultural best management practices, and to minimize contamination of groundwater. Key words: Soil-landscape, soil horizon, soil classification, sulphate, electrical conductivity, leaching
Factors influencing mineralizable carbon in a landscape with variable topography
Authors: Chan C. , Kay B D , Gregorich E G
Published: April 2011

Management-induced erosion has substantially increased the spatial variability in soil organic carbon (OC) stocks in landscapes with variable topography, but its impact on C dynamics is not well understood. The variability in cumulative C mineralization of samples from five positions in a landscape was examined in an incubation study and the effects of water content and depth within the A horizon were assessed. Mineralization was generally at a maximum at water contents between 80 and 95% water-filled pore space. The amount of C mineralized increased with OC content, but the proportion of the mineralizable OC decreased with increasing OC content. Few significant differences in C mineralization existed between surface and subsurface layers of the A horizon. The spatial patterns in maximum C mineralization were generally indicative of the patterns obtained when mineralization was calculated using spatial patterns of actual seasonal average water contents. This suggests the spatial pattern of maximum mineralization was not strongly influenced by variable hydrologic conditions on this site and reflects the spatial patterns in annual mineralization. The proportion of OC mineralized was not related to the proportion of the OC in particulate organic carbon (POC) or in the silt + clay fractions, but was significantly negatively related to the saturation of the clay + silt fraction with C. We speculate that the decline in the proportion of mineralized OC with increasing OC content reflects an increased proportion of the capacity of the silt + clay fraction to retain and physically protect OC within microaggregates. Key words: Erosion, deposition, mineralizable organic carbon, spatial variability
Influence of arbuscular mycorrhizae on soil P dynamics, corn P-nutrition and growth in a ridge-tilled commercial field
Authors: Landry Christine P , Hamel Chantal , Vanasse Anne
Published: April 2011

Ridge-tilled corn (Zea mays L.) could benefit from arbuscular mycorrhizal (AM) fungi. Under low soil disturbance, AM hyphal networks are preserved and can contribute to corn nutrition. A 2-yr study was conducted in the St. Lawrence Lowlands (Quebec, Canada) to test the effects of indigenous AM fungi on corn P nutrition, growth, and soil P in field cropped for 8 yr under ridge-tillage. Phosphorus treatments (0, 17, 35 kg P ha-1) were applied to AM-inhibited (AMI) (fungicide treated) and AM non-inhibited (AMNI) plots. Plant tissue and soil were sampled 22, 48 and 72 days after seeding (DAS). P dynamics was monitored in situ with anionic exchange membranes (PAEM) from seeding to the end of July. AMNI plants showed extensive AM colonization at all P rates. At 22 DAS, AMI plants had decreased growth in the absence of P inputs, while AMNI plants had higher dry mass (DM) and P uptake in unfertilized plots. The PAEM was lower in the AMNI unfertilized soils in 1998 and at all P rates in 1999, indicating an inverse relationship between P uptake and PAEM. At harvest, grain P content of AMNI plants was greater than that of AMI plants. In 1998, only AMI plants had decreased yield in the absence of P fertilization. In 1999, AMNI plants produced greater grain yield than AMI plants at all P rates. AM fungi improve the exploitation of soil P by corn thereby maintaining high yields while reducing crop reliance on P inputs in RT. Key words: Arbuscular mycorrhizae, ridge-tillage, soil P dynamics, corn, P nutrition
Soil and crop responses to long-term potato production at a benchmark site in northwestern New Brunswick
Authors: Rees H W , Chow T L , Gregorich E G
Published: April 2011

Concerns about deteriorating soil quality led to Agriculture and Agri-Food Canada establishing a network of 23 soil quality monitoring benchmark sites with the objective of providing a baseline data set for assessing change in soil quality and biological productivity of representative Canadian farming systems. A site (22-NB) was established in 1990 in northwestern New Brunswick to monitor changes in Podzolic and Brunisolic soils developed on coarse loamy till on a rolling landscape under intensive potato (Solanum tuberosum L.) production [potato-potato-barley (Hordeum vulgare L.) rotation] that was cultivated along the contour with variable grade diversions and a grassed waterway. Soil samples were collected in 1990 and again in 2000. Field saturated hydraulic conductivity (Kfs) at 10–20, 26–36 and 50–60 cm, earthworm counts and crop yield measurements were conducted annually. 137Cs data were collected in 1990 to estimate soil displacement at the site. Runoff and soil loss between May 01 and Nov. 30 were measured annually. The soil conservation system at site 22-NB has resulted in annual runoff and soil loss of only 9 mm and 311 kg ha-1, respectively. Measured values of 137Cs averaged 2114 Bq m-2 (70% of baseline). Changes in the Ap horizon properties between 1990 and 2000 included significant (P < 0.05) increases in available P (+ 86.7 mg kg-1) and K (+ 13.4 mg kg-1) and significant reductions in available Mg (−45.8 mg kg-1) and SOC (−0.51 g kg-1). The Kfs of 10- to 20-cm, 26- to 36-cm and 50- to 60-cm depths were 1.3, 1.0 and 1.0 cm h-1, respectively. Very few earthworms were present (0.05 worms m-2). The upper terrace was consistently the highest yielding in both potato and barley, while the lowest terrace was consistently the lowest yielding in both crops. Crop yields may have been affected by micro-climate and other soil differences as a result of site position.While the system of contour tillage with variable grade diversions and grassed waterway conserved both soil and water, the potato-potato-grain rotation did not maintain SOC levels or sustain earthworm populations. Associated heavy rates of fertilization also lead to increased levels of soil K and P. Key words: Soil quality, soil organic carbon, hydraulic conductivity, earthworms, runoff, water erosion
Response of no-till winter wheat to seed-placed ammonium nitrate fertilizer
Authors: Fowler D. B. , Brydon J.
Published: April 2011

Winter wheat (Triticum aestivum L.) can be successfully overwintered in most regions of the Canadian prairies if it is sown without prior tillage into standing stubble immediately after harvest of the previous crop. Soil nitrogen (N) is usually deficient in this production system and N fertilization is necessary to optimize yield and maintain minimum quality standards. In the present study, the effect of seed-placed (SP), early-spring broadcast (BC), and SP/BC combinations of ammonium nitrate fertilizer (AN) on winter survival, grain yield and protein production of winter wheat was investigated in 15 field trials conducted over a wide range of soil types and environmental conditions in Saskatchewan. Ammonium nitrate fertilizer placed in a 20-mm-wide band with Norstar winter wheat seed produced average grain yield responses for 34, 67, and 101 kg N ha−1 treatments that were 98, 84, and 71% of comparable BC treatments, respectively. Average grain protein yield responses for the 34, 67, and 101 kg ha−1 SP N treatments were 94, 82, and 74% of comparable BC treatments, respectively. Grain protein concentration responses were similar for comparable BC and SP N treatments. Yield responses for 34 kg N ha−1 SP and BC treatments indicated that AN could be seed-placed at low rates without significantly reducing N-use efficiency. However, significant reductions in winter survival potential in all trials where differential winterkill occurred suggested that even rates as low as 34 kg N ha−1 SP AN should be avoided when cultivars with marginal winter hardiness are utilized. Key words: Winter wheat, no-till, seed-placed N, yield, protein, winter survival
Soil management with cultivated fallows in humid and subhumid Africa
Authors: Adesina F. A.
Published: April 2011

This paper examines those variations in soil properties of woody fallows that may be expected as a result of the use of the tree Gliricidia sepium (Jacq.) in fallow management in the forest areas of Nigeria. A comparative analysis of fallows of the tree and natural fallows was carried out. The results show that differences might be expected between the soil under the two fallow types with respect to pH, boron and available phosphorus. It is suggested that the tree is a suitable species for fallow enhancement in terms of soil restoration but that its use would involve some modification of soil management practices such as the amount and type of fertilizers applied. Key words: Gliricidia sepium, fallow management, soil restoration, woody fallows
Effect of nitrogen source, placement and time of application on winter wheat production in Saskatchewan
Authors: Campbell C. A. , Selles F. , Nuttall W. , Wright T. , Ukrainetz H.
Published: April 2011

Saskatchewan producers growing primarily spring-seeded cereals may be interested in diversifying their cropping alternatives. Winter wheat (Triticum aestivum L.) could provide one possible option, but its management could cause conflict with the busy fall and early spring activities for spring-seeded crops. A study was conducted at five sites (Swift Current, 4 yr; Melfort, 4 yr; and Scott, Lashburn, and Loon Lake, 1 yr each) in four soil zones (Brown, Dark Brown, and Black Chernozems and Gray Luvisol). The effect of time of application of N (seeding to early spring), source of N (ammonium nitrate vs. urea), and method of application (broadcast, midrow band, and seed-placed) on yield and grain protein concentration were investigated. The results varied with site and year (weather). Time of N application only influenced yields at Swift Current (Brown soil) where application on cool unfrozen soil in mid-October was as good as application in early spring and better than at other times, and application onto frozen, snow-covered soil in December was least effective. At Swift Current and Melfort, grain protein concentration did not respond to time of application; however, at Scott, Lashburn and Loon Lake, protein was highest for spring-applied N, followed by mid-October, and lowest when N was applied on frozen snow-covered soil. The effect of N source rarely affected grain yield or protein and was dependent on site and method of placement. The dangers of seed-placing N, especially urea, on overwinter survival and yields were evident in 2 yr at Swift Current. There was rarely any difference in yield or grain protein concentration when N was banded or broadcast at seeding time. Taking into account convenience of operation, the most opportune time for Saskatchewan producers involved in growing both spring and winter wheat to apply N would be mid-October in the Brown soil zone. In the other soil zones, early spring would be best. Broadcasting the N was the most appropriate method of application at all sites. Urea would be chosen over ammonium nitrate because there was little advantage of one source over the other and urea is generally cheaper. Key words: Urea, ammonium nitrate, protein, grain yields, plant population
Iron status of crops in Prince Edward Island and effect of soil pH on plant iron concentration
Authors: Gupta Umesh C.
Published: April 2011

Field studies were conducted in Prince Edward Island (PEI) on the Fe nutrition of cereals and forages and to determine the relationship between plant Fe and soil pH. The Fe concentration in barley (Hordeum vulgare L.) and oats (Avena sativa L.) boot stage tissue (BST) and grain ranged from 35 to 65 and from 19 to 42 mg kg−1, respectively, in the control and from 38 to 57 and from 22 to 45 mg kg−1, respectively, in the soil applied Fe treatments. In the foliar applied Fe treatments, the cereal BST contained as much as 121 mg Fe kg−1 in the FeSO4.7H2O treatments and up to 86 mg kg−1 in the chelate-Fe treatment, but neither of these two sources increased Fe concentration in the grain. In the first cut of forages in the foliar treatments, the Fe was as high as 131 mg Fe kg−1, but no differences were generally found between the control and Fe treatments in the second cut. Over the soil pH ranges of 4.5–6.9, no consistency was found in the correlation coefficient (r) values between plant Fe and soil pH. In spite of the Fe concentrations as low as 19 mg kg−1 in cereal grain and 23 mg kg−1 in forages in the control treatments, no yield response to added Fe was found. However, the Fe concentrations as found in this study would be considered deficient for livestock and mineral supplements of Fe to the feeds may be desirable. Key words: Cereals, forages, soil pH, plant iron, acid soils
Effect of humic substances on photosynthetic sulphate assimilation in maize seedlings
Authors: Ferretti M. , Passera C. , Ghisi R. , Nardi S.
Published: April 2011

Maize plants were grown in nutrient solution containing 0, 15, 30, 50 mg organic carbon L−1 of humic substances (HS) (M.W. < 12 KDa) extracted from a cambisol. After 14 d of growth the second and third leaves were collected and analyzed for chlorophyll and protein content and for the activities of ATP sulphurylase (ATP-s) and O-acetylserine sulphydrylase (OAS-s) to evaluate the effect of HS on maize sulphate assimilation pathway. Humic substances induced significant decreases in chlorophyll content, whereas the protein level slightly increased up to 30 mg L−1 of HS. ATP-s and OAS-s were positively affected by HS. The stimulations were different according to the enzyme and leaf investigated. Our results suggest that HS might play an important role in the efficiency of maize plants to assimilate sulphate. Key words: ATP-sulphurylase, chlorophyll, humic substances, maize, O-acetylserine sulphydrilase
Trace element uptake by two British Columbia forages as affected by poultry manure application
Authors: Bomke A. A. , Lowe L. E.
Published: April 2011

Field experiments evaluated yield response to deep-pit poultry manure application to barley on a clay soil near Prince George and a grass-legume forage on a silty clay loam soil near Chilliwack, B.C. Substantial dry matter yield increases were measured at manure applications up to 20 t ha−1. Subsamples of both crops and the poultry manure were analyzed for Cu, Zn, Mn, Ba, Pb, Ni, Cr, Cd, B and Co. Selenium analyses were made on selected crop samples. There were no indications of toxicity problems even at 40 t ha−1, the highest application. Copper and Zn concentrations in forages were increased by the poultry manure and the Mn/Cu ratio tended to decrease with manure application. Key words: Orchardgrass, ladino clover, barley, micronutrients
Grazing impacts on soil water in mixed prairie and fescue grassland ecosystems of Alberta
Authors: Naeth M. A. , Chanasyk D. S. , Rothwell R. L. , Bailey A. W.
Published: April 2011

Reduced soil water under grazing is generally attributed to reduced infiltration as livestock trampling compacts the soil surface. Grazing can also have the opposite effect on soil water through reduced evapotranspiration when vegetation is removed. On the Canadian Prairies, grazing impacts on soil water have been assessed in short-term studies but impacts of long-term grazing have not been documented. In this study, impacts of long-term grazing on soil water were assessed in mixed prairie, parkland fescue grassland, and foothills fescue grassland ecosystems of southern and central Alberta. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Soil water was measured with a neutron probe to a depth of 1 m from April through October over three growing seasons. Normal patterns of soil water recharge in autumn and spring and soil water depletion in summer due to evapotranspiration were not altered by grazing. Fluctuations in soil water were most pronounced in the uppermost 30 cm but still evident in the 30- to 50-cm and 50- to 80-cm depth intervals. Heavy intensity and/or early season grazing had a greater impact on soil water than light intensity and/or late season grazing. Season of grazing affected soil water more under light than heavy grazing intensities. On most sampling dates, soil water in grazed treatments was lower than in the ungrazed control, particularly in the 30- to 50-cm and 50- to 80-cm depth intervals. Differences between the control and grazed treatments were least pronounced during the summer months with evapotranspiration depleting soil water reserves in all treatments. Key words: Soil water, grazing, rangelands, water uptake
Phytotoxicité des matériaux ligneux frais et compostés utilisés comme amendements organiques des sols
Authors: Beauchemin Suzanne , Laverdière Marc R. , N’dayegamiye Adrien
Published: April 2011

A germination test with cress (Lepidium sativum L.) was carried out to evaluate the phytotoxic effects of extracts from fresh and composted tree clippings. Water-soluble extracts from unground and ground material were compared with a soil solution and distilled water in relation to their effect on germination and plant root development. Water-soluble and ethanol-soluble extracts from fresh tree clippings were strongly acidic, but they were neutral for the composted material. Greater quantities were extracted by water and alcohol from fresh material than from composted material. Water-soluble products extracted from fresh ligneous materials decreased the rate of germination of cress very significantly compared with those obtained from composted tree clippings. Grinding the clippings further reduced the germination rate, through the apparent liberation of more phytotoxic products. Composting of tree clippings significantly decreased the phytotoxicity of the organic amendment. Key words: Composting, cress, germination, phytotoxicity, wood residues, tree clippings