bluuebunny/crossref_metadata_2025 huggingface dataset:
HYBRID MATURITY AND THE RELATIVE IMPORTANCE OF GRAIN AND STOVER FOR THE ASSESSMENT OF THE FORAGE POTENTIAL OF MAIZE GENOTYPES GROWN IN MARGINAL AND NON-MARGINAL ENVIRONMENTS
Authors: FAIREY N. A.
Published: March 2010

Ninety-seven maize hybrids of differing maturities and genetic constitutions were grown at three somewhat dissimilar environments (Agassiz, Sumas and Surrey) in British Columbia. The study attempted to elucidate the nature of relationships existing between important performance characteristics of maize for both forage (whole crop) and grain production. Forage yield was linearly related to grain yield at each location and the relationship was distinct for each location. However, grain yield was not a good indicator of forage productivity, with coefficients of determination of 51.0, 33.1 and 13.5% for Agassiz, Sumas and Surrey, respectively. Maize hybrids best adapted for forage production were somewhat later in corn heat unit (CHU) maturity ratings than those adapted for grain production. However, the CHU rating system appears to be less useful for making practical management decisions on the most suitable hybrid maturity for the production of forage than it is for the production of grain. At each location, forage DM content was dependent on the DM content of the stover and the proportion of total DM as grain or in the ear. In future, greater emphasis should be given to evaluating maize varieties independently for forage and grain production, and to the quality and yield of the stover component of forage maize.
EMERGENCE FROM BURIED SEED AND GERMINATION OF EXHUMED SEED OF FALL PANICUM
Authors: ALEX J. F.
Published: March 2010

Nylon mesh envelopes containing 200 seeds of fall panicum (Panicum dichotomiflorum Michx. var. geniculatum (Wood.) Fern.) and 20 cc sterile soil were buried 1–20 cm below the surface of silt loam and gravelly loam in a farmer’s field in November 1971. In April 1972 exhumed seeds germinated from 73.4 to 91% in 17 °C dark 10 h/27 °C light 14 h, the percentage increasing with depth. Seedling emergence during May-September 1972 averaged 48, 45 and 5% from 1-, 2-, and 5-cm depths in silt loam but 1, 19, and 10% from the same depths in gravelly loam and was erratic during the second growing season. No emergence came from 10- or 20-cm depths, nor from any depth after 2 yr. Germination of seed exhumed from the 20-cm depth was 80.75, 37.75, and 10.5% for the silt loam soil, and 46.5, 21, and 2.5% for the gravelly loam soil at sampling times of 12, 29 and 54 mo, respectively. Germination of seed exhumed from shallower depths was less in each instance except from the 5-cm depth in silt loam at 29 mo when it was the same. Potential reproduction (sum of emergence plus subsequent germination) decreased with depth down to the 10-cm level in both soils, but increased again with greater depth (at 20 cm).
THE EFFECT OF SODIUM HYPOCHLORITE, GIBBERELLIC ACID AND LIGHT ON SEED DORMANCY AND GERMINATION OF STINKWEED AND WILD MUSTARD
Authors: HSIAO A. I.
Published: March 2010

Light treatment alone is capable of inducing 100% germination of stinkweed seeds (Thlaspi arvense L.), but not of wild mustard seeds (Sinapis arvensis L. (Brassica kaber (DC.) Wheeler var. pinnatifida (Stokes) Wheeler)). On the contrary, gibberellic acid (GA3) alone is able to induce complete germination in wild mustard, but effected only a slight promotion of germination of stinkweed seeds. Germination of both species increased with increasing time of immersion in 6% sodium hypochlorite (NaOCl). The NaOCl treatment mimics the effect of acid scarification or dissection in making seeds more porous, removing the barriers to gas exchange and GA3 penetration, and increasing sensitivity to light treatment. However, prolonged NaOCl treatment resulted in either poor germination or seed disintegration. Dormancy of a genetically distinct early-flowering strain of stinkweed can be broken only by the combination of NaOCl, GA3 and light, indicating a high degree of variability in germination responses to various sets of conditions.
EFFECTS OF SALINIZATION TREATMENTS ON GROWTH AND SOME RELATED PHYSIOLOGICAL ACTIVITIES OF SOME LEGUMINOUS PLANTS
Authors: AHMED A. M. , HEIKAL M. M. , ZIDAN M. A.
Published: March 2010

When subjected to salinization levels of 00, 20, 40 and 60 meq NaCl/L, the kidney bean cultivars Harvester and Contender and cowpea cultivars Asmarly and Creamy 7 exhibited significant changes in their physiological activities. The trends and magnitudes of these changes depended on the plant variety as well as on the level of salinization. Generally, it was found that while stomatal frequency and transpiration rate were significantly reduced, water content was considerably elevated. Biosynthesis of pigments and photosynthetic activity and consequently leaf area and dry matter accumulation were considerably reduced as the concentration of NaCl in the nutritive medium increased. Mineral composition also exhibited significant changes, but the dominant feature was the high accumulation of sodium in salinized plant tissues.
TYEE STRAWBERRY
Authors: DAUBENY HUGH A.
Published: March 2010

Tyee strawberry (Fragaria × ananassa Duch.) is a new cultivar which produces relatively high yields of firm fruit on erect scapes. It appears equally well-adapted to fresh and to processing market outlets. It is tolerant or resistant to several important strawberry pests including viruses, red stele, powdery mildew, fruit rot and two-spotted spider mite.
COLLECTION AND SEPARATION OF YELLOW NUTSEDGE TUBERS
Authors: GUTMAN J. , WATSON A.K.
Published: March 2010

The construction and use of a soil sampler for collection of yellow nutsedge (Cyperus esculentus L.) tubers is described. A washing apparatus was also developed for the separation of nutsedge tubers from soil samples.
PHOTOPERIOD RESPONSE CHARACTERISTICS CONTROLLING FLOWERING OF NINE CROP SPECIES
Authors: MAJOR D. J.
Published: March 2010

The flowering response of two cultivars of wheat, oats, rye, Polish rape, Argentine rape, flax, sorghum, and soybeans to photoperiods between 12 and 24 h at 1-h intervals was studied in controlled environment cabinets. The results indicated that in long-day species, the relationship between time to heading or first flower and photoperiod was linear and decreased as photoperiod increased to the minimum optimal photoperiod (MOP). Within the range of optimal photoperiods, the number of days to heading or flowering was constant and provided a measure of the length of the basic vegetative phase (BVP). The slope of the response line obtained in non-optimal photoperiods provided an estimate of photoperiod sensitivity. The three characteristics, MOP, BVP, and photoperiod sensitivity, were equally valid for the short-day species except that as daylength increased, there was a linear increase in time to flowering as daylength increased above a maximum optimal photoperiod (MOP). For three of four short-day cultivars, there was also a critical photoperiod above which flowering occurred in a constant number of days. Data suggest separate genetic controls for each of the response characteristics.
EFFECT OF NITROGEN SUPPLY ON THE SEED SET OF SPRING WHEAT AND BARLEY
Authors: CAMPBELL C. A. , LEYSHON A. J.
Published: March 2010

Applications of NO3-N increased seed set of wheat grown under hot, moist conditions. An attempt was made to determine whether this improvement in seed set was due to improvement in plant nutrition or to NO3 poising the soil Eh above that at which phytotoxic ethylene is produced. Two pot experiments were carried out in a controlled environment chamber at diurnal temperatures 27/12 °C and slightly above field capacity. NO3-N or NH4-N with N-Serve ® were applied to Manitou wheat at rates of 45, 90, 135, and 180 kg N/ha in the first experiment, and to Manitou wheat and Conquest barley at rates of 23, 45, 90, 180 and 360 kg N/ha in the second. N-Serve successfully maintained the nitrogen in the NH4 form throughout the experiment. In both experiments, the seed set of the primary and secondary florets of wheat was directly proportional to the NO3-N rate. Wheat plants fed NH4-N exhibited significantly higher seed set than the NO3-N-fed plants at the low nitrogen rates. Seed set of lateral spikelets of barley was unaffected by rate, but the NH4-N-fed plants tended to produce slightly higher seed set. Ethylene was not detected in any of the soils. Since NH4-N corrected the seed set problem even at low levels of nitrogen, it was concluded that poor nitrogen nutrition and not the production of soil ethylene was responsible for poor seed set of wheat.
QUALITY CHANGES OCCURRING IN SMALL LOTS OF DRY AND MOIST RAPESEED DURING STORAGE
Authors: MILLS J. T.
Published: March 2010

Small, 25-kg quantities of moist and dry Brassica napus L. ’Tower’ rapeseed were stored in drums located outdoors for 65 wk. Quality changes occurring in the moist (10.9–15.0% moisture content) rapeseed, which was deliberately allowed to spoil, were compared to those in dry (4.3–4.9% moisture content) seed. Moist seeds in the first 7 wk had high respiration and declined in quality during the 65 wk of storage as indicated by decreased seed germination, increased leakage of seed electrolytes, and increased free fatty acid (FAV) levels. Levels of post-harvest molds, including Aspergillus candidus, A. glaucus group species, A. versicolor, Penicillium verrucosum var. cyclopium and Wallemia sebi, also increased. Mycelia of P. verrucosum var. cyclopium caused seeds of 12.9–17.8% moisture content to become cemented together at the bottom of some drums necessitating removal of samples by chipping at 65 wk. Dry seeds, originally 11.2–12.2% moisture content before drying, had low seed respiration, high germination, low levels of most post-harvest molds but also moderate levels of P. verrucosum var. cyclopium and high FAV and therefore were also of low quality. Drying of the seeds occurred too late to prevent initial rapid loss in seed quality caused by seed enzymatic action and Penicillium activity; to be effective, drying of high moisture seeds should be carried out immediately after combining.
EFFECTS OF MATURITY ON FRUIT COMPOSITION AND SUSCEPTIBILITY TO SURFACE DAMAGE IN SWEET CHERRIES
Authors: LIDSTER P. D. , MULLER K. , TUNG M. A.
Published: March 2010

Fruit weights, soluble solids, and dry matter generally increased and fruit N generally decreased with maturity. Mesocarp Ca and Zn in response to fruit maturity were inconsistent in the 2 yr studied. Mesocarp Mg and K levels increased within the commercial range of maturity in the 2 yr studied. Total and water-soluble pectic fractions decreased linearly with fruit maturity. Alcohol-insoluble solids and fruit firmness were a minimum at intermediate maturities and corresponded to the maturity at which rapid fruit growth occurred. The incidence of bruises was highest in more mature fruit in 1977 while the incidence of surface marks and pitting were at a maximum when fruit reached the red color corresponding to minimum acceptable commercial maturity. In 1978, the incidence of surface marks and bruises were at a maximum at intermediate maturities. Resistance to surface pitting in mature fruit in 1978 was associated with high dry matter, high alcohol-insoluble solids and low N content.
UNHEATED ENVIRONMENTS FOR OVERWINTERING NURSERY PLANTS IN CONTAINERS
Authors: DESJARDINS R. L. , CHONG CALVIN
Published: March 2010

Nineteen unheated environments, including 12 under plastic structure, 6 under structureless blanket cover, and a control, were monitored and compared for their effectiveness in protecting nursery plants in containers during the winter. A relatively good linear relationship was found between the minimum daily air temperatures outside (control) and the minimum daily temperatures of both air and container within the various environments. From these relationships, regression coefficients were found that could be used for predicting the minimum air and container temperatures within the protected environments using outside air temperature. As indicated by post-winter storage condition of selected cultivars, all environments with snow cover under plastic structure or under blanket cover provided good plant protection, while similar environments without snow cover were less effective. Over-the-canopy protection with Microfoam insulation during the coldest months provided good protection in polyhouse environments without snow cover. Based on the regression coefficients and on the post-winter storage condition of plants, the environments were classified into three major groups: regression coefficients ranging from 0.2 to 0.4 for environments providing good protection; from 0.4 to 0.5 for those providing intermediate protection; and from 0.5 to 0.7 for those providing poor protection. A technique is presented to determine which types of environment are likely to be successful in other locations across Canada.
THE BIOLOGY OF CANADIAN WEEDS.: 42. Stellaria media (L.) Vill.
Authors: TURKINGTON ROY , KENKEL NORMAN C. , FRANKO GAIL D.
Published: March 2010

This paper provides a summary of biological data on Stellaria media (L.) Vill., commonly known as chickweed. It is found throughout most of the world and is present in all Canadian provinces and both territories, being particularly abundant in British Columbia and eastern Canada. Chickweed is a weed of grain fields, young pastures, lawns, and gardens, and can be controlled by the use of several common herbicides.
FACTORS INFLUENCING 1,8-NAPHTHALIC ANHYDRIDE ACTIVITY AS AN ANTIDOTE TO BARBAN IN OATS
Authors: THIESSEN E. P. , STEPHENSON G. R. , ANDERSON G. W.
Published: March 2010

NA (1,8-naphthalic anhydride), a seed-applied herbicide antidote, significantly reduced barban (4-chloro-2-butynyl-m-chlorocarbanilate) injury to oats (Avena sativa L.) in both growth room and field studies. However, at the application rate of 0.75% by seed weight, recovery from barban injury in oats was incomplete under some conditions. Despite pretreatment with NA, the cultivars Rodney, Garry, or Stormont oats did not recover from postemergence barban applications (0.42 kg/ha) while seven other cultivars recovered completely from barban injury. The effectiveness of NA as a barban antidote was consistent at low, normal, or high fertility levels. At 0.75% by seed weight, NA was highly effective as a barban antidote in oats grown in light sandy soils but was much less effective in silty clay soils. NA phytotoxicity to oats was noted when NA-treated oat seed was stored for long periods of time prior to planting. Much of the variation in preventing barban injury was overcome with formulations or methods that facilitated NA applications to oat seed at rates as high as 1.5% by seed weight.
EPTC COMPARED WITH EPTC + ANTIDOTES FOR ALFALFA ESTABLISHMENT
Authors: IVANY J. A.
Published: March 2010

Addition of either of the antidotes R-25788 (N,N-diallyl-2, 2-dichloroacetamide) or R-29148 (2,2,5-trimethyl-N-dichloroacetyloxazolidine) to EPTC (S-ethyl dipropylthiocarbamate) did not protect alfalfa (Medicago sativa L.) from injury by the herbicide as reflected in dry matter yield.
CARBOHYDRATE AND PROTEIN ACCUMULATION IN THE DEVELOPING FIELD PEA SEED
Authors: HOLL F. B. , VOSE J. R.
Published: March 2010

Changes in quality factors during seed maturation were examined in yellow smooth-seeded field peas (Pisum sativum L. ’Trapper’) under different nitrogen (N) regimes. Sucrose was the sole oligosaccharide (17% of dry weight) at 15 days post-anthesis, but at full seed maturity (80 days post-anthesis) had decreased to 2.2% of seed dry weight. At maturity, raffinose, stachyose, and verbascose content had reached concentrations of 0.6, 1.8, and 2.3%, respectively. Total oligosaccharide content remained constant regardless of variation in seed protein concentration, and was unaffected by applications of N fertilizer. Seed protein (%) was found to be variable and positively correlated with N fertilizer treatments. Seed protein (dry basis) decreased during seed maturation. This decrease was most evident in the absence of added N fertilizer. Symbiotic fixation (acetylene reduction) was low in all treatments and made little contribution to plant N content. Fixation in the absence of added N was insufficient to maintain seed N at levels comparable to those observed in the high-N fertilizer treatments. The constancy of oligosaccharide content under the different fertilizer regimes indicated that the content of these components might be more amenable to genetic manipulation via selection rather than by varying management practices.
HARVEST INDEX AS A SELECTION CRITERION FOR GRAIN YIELD IN TWO SPRING WHEAT CROSSES GROWN AT TWO POPULATION DENSITIES
Authors: NASS H. G.
Published: March 2010

The use of harvest index as a selection criterion for grain yield in F2 populations of spring wheat (Triticum aestivum L.) grown at two population densities was investigated. Harvest index was useful in delineating yield differences between lines for both crosses. The F4 lines selected in F2 for a high harvest index yielded about 9% more per plot in 1978 than F4 lines having a low harvest index in F2. Generally, lines selected at the higher commercial seeding rate yielded more than lines selected at the lower plant density. In 1979, a heavy Fusarium infection reduced the mean grain yield of the F6 lines and suppressed any significant response to selection resulting from population density and harvest index in F2. While selection based on high harvest index at low population density can be used to select higher yielding plants it was not as effective as selection at high population density which more closely approximates commercial crop densities. Additional research is needed before the use of harvest index as a selection tool in wheat breeding programs can be recommended for use in Atlantic Canada.
SEEDING CEREALS BY AIR AND GROUND
Authors: BARNETT G. M. , COMEAU J. E.
Published: March 2010

In this trial, oats (Avena sativa ’Alma’), wheat (Triticum aestivum ’Opal’) and barley (Hordeum vulgare ’Loyola’) seeded extra early by air did not compare favorably with these cereals seeded by ground methods 2–3 wk later. Cereals sown by air did not penetrate the soil and were unevenly dispersed. Because covering operations were not possible, much of the exposed seed was eaten by birds and germination was low. This resulted in reduced cereal stands and grain yields, and increased weed population. The conventional drill seeder was the best machine to seed cereals, in terms of the above parameters. The broadcast fertilizer spreader followed immediately by alight harrowing was a close second. Passage of the spring-tooth harrow before drilling or after seeding by broadcast methods greatly enhanced population and yield and reduced weed numbers. Because broadcast seed must be covered, date of seeding, even by air, will be determined by the date at which the soil is dry enough to permit harrowing.
THE PRODUCTIVITY AND CHEMICAL COMPOSITION OF ALTAI WILD RYEGRASS AS INFLUENCED BY TIME OF IRRIGATION AND TIME AND RATE OF N FERTILIZATION
Authors: LAWRENCE T. , WINKLEMAN G. E. , WARDER F. G. , KORVEN H. C.
Published: March 2010

The effects of five times of irrigation, two times of N-fertilizer application and four rates of N-fertilizer application on the seed yield, dry matter yield, N, P, NO3-N, Ca, Mg, and K content and K/(Ca+Mg) ratio of Altai wild ryegrass (Elymus angustus Trin.), were studied from 1974 to 1977. No clear-cut methods to maximize the seed yield on irrigated land were found. Highest dry matter yields were obtained from grass given three irrigations and 400 kg N/ha per year. Spring applications of N fertilizer resulted in forage with a higher N content than fall applications. The N content of the forage increased with increasing levels of N fertilizer, whereas the P content of the forage was reduced by N fertilizer applications. Toxic levels of nitrates can be expected from spring applications of 400 kg N/ha. This danger was reduced if N fertilizer was applied in the fall. The Ca, Mg and K content increased with increasing levels of N fertilizer. The K/(Ca+Mg) ratio indicated that there was little danger of grass tetany problems in animals fed fertilized Altai wild ryegrass.
INFLUENCE OF TEST PERIOD AND SEQUENCE OF YEARS ON RESULTS WITH PERENNIAL FORAGE CROPS IN A SEMIARID REGION
Authors: KILCHER M. R.
Published: March 2010

A perennial forage test comprising six different grasses, each in mixture with one alfalfa cultivar, was seeded adjacently in 1966, 1968 and 1970. Each test was identical in design and used the same seed lot. The three tests were each run for 9 consecutive yr, ending in 1975, 1977 and 1979, respectively. Measurements included annual and seasonal precipitation, progressive stand and component changes and dry matter (DM) yields from two to three cuts per year. Statistical analyses of the collected data were done for each test for varying periods of years during the respective 9-yr periods. Main conclusions were that particular blocks of years tended to give similar and comparable results provided that the number of sequential years exceeded five, and also, provided first-year data were excluded.
THATCH CONTROL ON CREEPING BENTGRASS TURF
Authors: EGGENS J.L.
Published: March 2010

The effectiveness of thatch control practices commonly employed in Ontario on Penncross creeping bentgrass turf maintained as a putting green was evaluated from July 1976 to October 1979. The most effective treatments were coring and vertical mowing followed by topdressing, and topdressing alone. The least amount of winter injury occurred in plots where coring was followed by topdressing. Coring reduced thatch accumulation more than did vertical mowing. Vertical mowing increased winter injury and annual bluegrass content in the plots more than did coring. Thatch accumulation was less at the 5-mm than at the 8-mm mowing height. Nitrogen treatments of 2 and 4 kg N∙100 m−2 did not influence thatch accumulation.
THE EFFECTS OF HYBRID MATURITY, DATE OF PLANTING, AND DATE OF HARVESTING ON GROWTH AND DEVELOPMENT OF FORAGE MAIZE
Authors: FAIREY N. A.
Published: March 2010

A study was conducted to concurrently evaluate the influence of hybrid maturity, date of planting and date of harvesting on the growth and development of forage maize in the Lower Mainland of British Columbia. The maturities of the four hybrids ranged from 2600 to 3300 corn heat units (CHU). There was an early (29 April) and a later date of planting (20 May) with three dates of harvesting (15 and 29 Sept., 13 Oct.). Early planting increased leaf area/plant in mid-July but resulted in shorter plants at maturity with smaller maximum leaf areas. Early planting increased dry matter (DM) yields of shoots (total forage) and grain by 1.0 and 1.9 t/ha, respectively, and resulted in 0.9 t/ha reduction in stover (stem + leaf + husk) DM yield. The hybrid that produced the highest grain yields and had the greatest proportion of DM as grain was outyielded for shoot DM production by a lower grain-yielding hybrid. Shoot DM yields did not increase significantly between the second and final dates of harvesting, whereas grain DM yield and the proportion of shoot DM as grain continued to increase with each successive harvest. Over the 4-wk harvesting period, the DM content of the grain increased, on average, at a rate of 4% per week whereas the DM content of the stover increased by about 1% per week; shoot DM content increased at 2% per week. For the periods of grain growth studied, shoot DM content (%) of each hybrid responded to the CHU accumulated from 50% silking to harvest at an equal and linear rate, with each 1% increase in shoot DM content requiring 41 CHU. However, the four hybrids were grouped in two pairs with significantly different y-intercepts (at shoot DM contents of −0.3 and 1.6%). The differences in CHU requirement during grain filling might be genetically exploited to improve the productivity of forage maize without reducing DM content. The importance of selecting hybrids of appropriate maturity and of maximizing the use of the growing season to produce high-quality forage in marginal maize growing regions is emphasized.
BEDFORD BARLEY
Authors: WOLFE R. I.
Published: March 2010

Bedford is a six-rowed feed barley developed at the Agriculture Canada Research Station, Brandon, Manitoba, from a cross involving Cree, Keystone and Husky. Its main attributes are a substantial yield advantage over existing cultivars in the barley growing areas of eastern and central Manitoba, excellent straw strength and test weight.
POST-HARVEST RESPIRATION RATES AND INTERNAL CO2 CONCENTRATION IN SUGAR BEET ROOTS
Authors: COLE D. F.
Published: March 2010

A significant relationship (r = 0.85**) was found between internal CO2 concentration and respiration rate in sugar beet (Beta vulgaris L.) roots 60 days after harvest. Internal CO2 concentration differed among commercial cultivars. The data indicate that lines with low or high internal CO2 concentration can be selected.
Managing excess water in Canadian prairie soils: A review
Authors: Bedard-Haughn A.
Published: March 2010

"Excess water" conditions develop when a soil is unable to transmit water, leading to the onset of saturated conditions harmful to soils and crops. Negative agricultural impacts include reduced trafficability, physical damage to crops under hypoxic or anoxic conditions, increased salinity or sodicity, reduced nutrient availability and uptake, and increased incidence of weeds and pests. There are two main objectives in managing landscapes prone to excess water, both of which must consider soil and landform characteristics. The first is to maximize infiltration and conductivity through tillage and residue management. The second is to remove water from the soil profile as quickly as possible through drainage or the adoption of high water use plants such as alfalfa (Medicago sativa), which increase water losses through transpiration. Changes to the overall cropping system can also be made, including selecting crops and forages that have shown reduced sensitivity to excess water, applying seed treatments that encourage the development of water-tolerant traits, timing fertilizer application to correspond with maximum plant uptake, and incorporating high water use crops into the rotation. Recent work from Australia suggests that management of excess water requires a multi-disciplinary approach; however, little research has been done on this problem in the semiarid to sub-humid Canadian Prairies. Key words: Waterlogging, beneficial management practices, infiltration, drainage
Opportunities for improved fertilizer nitrogen management in production of arable crops in eastern Canada: A review
Authors: Zebarth B J , Drury C F , Tremblay N , Cambouris A N
Published: March 2010

There is increasing public pressure to reduce the environmental impacts of agricultural production. Therefore, one key challenge to producers is to manage their crop production systems in order to minimize losses of nitrogen to air or water, while achieving crop yield and quality goals. Many strategies have been developed in recent years to meet this challenge. These include: development of new tools to measure crop N status in order to refine in-season fertilizer N management, development of new soil N tests to improve prediction of soil N supply, development of new fertilizer N products with release patterns more closely matched to crop N uptake patterns, and development of site-specific N management strategies. We review the opportunities and limitations to these new strategies within different arable crop production systems under the humid and sub-humid soil moisture regimes present in eastern Canada. Future research opportunities to improve the efficiency of fertilizer N utilization include development of practical methods to predict the magnitude of soil N mineralization; refinement of decision-making processes which take into consideration the crop N status and soil properties as a basis for variable rate fertilizer N application; development of affordable controlled-release fertilizer N products with improved N release characteristics; development of practical methods for capturing and recycling nutrient-laden drainage water; development of gene expression profiling based techniques to identify crop N stress; and application of crop genomics and molecular breeding techniques to accelerate the development of new cultivars with increased N use efficiency. Key words: Soil N tests, plant N tests, nitrogen fertilizers, nitrogen cycling
Trace elements in Ontario soils - mobility, concentration profiles, and evidence of non-point-source pollution
Authors: Sheppard S C , Grant C A , Drury C F
Published: March 2010

Agricultural soils are the recipients of trace elements from general atmospheric pollution and from agricultural inputs such as fertilizer, feeds and urban biosolids. These input fluxes are usually small, and there are processes such as leaching and crop off-take to counterbalance the trace element inputs. Thus, it is difficult to evaluate the changes of trace element concentrations in agricultural soils. This paper examined a survey of 59 soil profiles in Southern Ontario, combining analysis of ~50 elements in three soil depths and corresponding measurements of the soil solid/liquid partition coefficient, Kd. The profile data were adjusted for yttrium concentrations to account for vertical particle migration. Increased concentration in the surface profile relative to the subsurface was considered an indication of enrichment, indicating the possible effects of human activity. For most elements, the surface (0–15 cm) and subsoils (30–60 cm) had similar concentrations. The notable exceptions were Cd, Pb, Sb, Se, Nb, U, and Zn, where surface soils had 1.4- to 2.2.fold higher concentrations than subsoils. Most of these increases can be attributed to human activity. Additional interpretation using the Kd data was useful to identify Ba and Mo as potentially among the contaminant elements. Surface soil concentrations of these elements were not markedly elevated compared with the subsoil, but their Kd values indicated that they were sufficiently mobile that depletion would be expected. Thus, perhaps continued input has supported the concentrations of Ba and Mo in the surface soils. Both are noted contaminants in dust from urban sources. Thus, the results show that several elements that are often of concern because of environmental toxicity or health impacts are at elevated concentrations in agricultural soils, and because these are rural locations the implication is that this has resulted from non.point.source pollution.Key words: Kd, partition coefficient, leaching, metals, cadmium
Using a sequential density and particle-size fractionation to evaluate carbon and nitrogen storage in the profile of tilled and no-till soils in eastern Canada
Authors: Gregorich E G , Carter M R , Angers D A , Drury C F
Published: March 2010

Tillage influences the retention and storage of organic matter (OM) in soil. We used a sequential density and particle-size fractionation to evaluate the total quantity and distribution of organic carbon (C) and nitrogen (N) in the profile of soils under mouldboard ploughing and no-till. Cores (0-60 cm) from four long-term tillage studies (in Prince Edward Island, Quebec, and two sites in Ontario) on soils of different textures, from sandy loam to clay were collected and divided into six depth increments. Four soil OM fractions were isolated on the basis of size and density from each sample. At two sites the standing stocks of C and N were larger in tilled than in no-till soil profiles at depths slightly greater than plough depth; tillage effects were also evident at a third site, where the mass of C in a layer close to the depth of ploughing was greater in tilled soils. Ploughing also had a substantial and consistent positive effect in all four soils on the quantity of C (and in some cases N) protected within aggregates, particularly at or near the bottom of the plough layer, and sometimes in surface soil layers. We attribute differences observed in whole soil C and N due to tillage mostly to differences in mineral-associated OM, particularly in soils with heavier textures, but the other size and density fractions could, together, account for as much as 25% of the difference. Because the C capacity level was not reached in heavy-textured soils, these soils show greater potential for further accumulation of C in the soil profile than coarse-textured soils, especially near the bottom of the plough layer.Key words: Light fraction, soil organic matter, soil tillage, physically-protected organic matter, no-till, soil texture
Macroaggregate-associated physical and chemical properties of a no-tillage chronosequence in a Miamian soil
Authors: Ochoa C. G. , Shukla M. K. , Lal R.
Published: March 2010

No-tillage (NT) has been shown to increase macroaggregate stability and soil organic carbon (SOC). Our objective was to quantify the effects of NT duration and slope position on macroaggregate-associated bulk density (ρb), available water content (AWC), hydrolysable and nonhydrolysable OC concentrations in fields under corn rotation. All fields were on Oxyaquic Hapludalfs (Alfisols) classified as Miamian soil. Macroaggregates (5-8 mm diameter) were separated from triplicate soil samples collected from 0-10 and 10-20 cm depths of the summit slope (SS) and toe slope (TS) positions from four fields under NT for the past 15 yr (NT15), 10 yr (NT10), 6 yr (NT6) and also from a chisel-tilled field (NT0) to a depth of 20 cm. At the SS position, macroaggregate-associated hydrolysable and nonhydrolysable OC were greater for NT15 than NT6 in both depths. At the TS position, hydrolysable OC was greater for NT10 than NT6 in the 0-10 cm depth only. Macroaggregate-associated AWC and hydrolysable OC were positively related to the NT duration, especially at the SS position. A positive correlation was obtained between water-stable macroaggregates (WSA) and hydrolysable OC at both depths and slope positions. A negative correlation between WSA and nonhydrolysable OC was observed at SS and TS positions in the 0-10 cm depth only. The increase in aggregate-associated hydrolysable OC at the SS position of fields under NT for 15 yr indicates that C accretion in macroaggregates is likely dependent on the continuation of NT.Key words: No-tillage, macroaggregate-associated available water content, hydrolysable carbon, nonhydrolysable carbon, macroaggregate stability
Spatial relationship between soil hydraulic and soil physical properties in a farm field
Authors: Biswas A , Si B C
Published: March 2010

The relationship between soil properties may vary with their spatial separation. Understanding this relationship is important in predicting hydraulic parameters from other soil physical properties. The objective of this study was to identify spatially dependent relationships between hydraulic parameters and soil physical properties. Regularly spaced (3-m) undisturbed soil samples were collected along a 384 m transect from a farm field at Smeaton, Saskatchewan. Saturated hydraulic conductivity, the soil water retention curve, and soil physical properties were measured. The scaling parameter, van Genuchten scaling parameter α (VGα), and curve shape parameter, van Genuchten curve shape parameter n (VGn), were obtained by fitting the van Genuchten model to measured soil moisture retention data. Results showed that the semivariograms of soil properties exhibited two different spatial structures at spatial separations of 20 and 120 m, respectively. A strong spatial structure was observed in organic carbon, saturated hydraulic conductivity (Ks), sand, and silt; whereas a weak structure was found for VGα and VGn. Correlation circle analysis showed strong spatially dependent relationships of Ks and VGα; with soil physical properties, but weak relationships of θs and VGn with soil physical properties. The spatially dependent relationships between soil physical and soil hydraulic parameters should be taken into consideration when developing pedotransfer functions. Key words: Spatial relationship, geostatistics, linear coregionalization model, principal component analysis, pedotransfer function
A century of planting trees: Musings on one hundred years of research
Authors: Janzen H. H.
Published: March 2010

Guest Essay: A century of planting trees: Musings on one hundred years of research
Evaluation of soil texture data for estimating soil water retention curve
Authors: Ghanbarian-Alavijeh B , Liaghat A M
Published: March 2010

The soil water retention curve (SWRC) is one of the basic characteristics used in determining soil hydraulic properties, including unsaturated hydraulic conductivity. As its measurement is time consuming and difficult, much effort has been expended to develop indirect methods, such as pedotransfer functions and empirical relationships, to estimate SWRC. In this study, three methods were evaluated based on estimation of retention models parameters and, consequently, the soil water retention curve. For this purpose, soil data collected from three data bases, totaling 72 soil samples with 11 different textures, were used in this study. The statistical parameters such as: MR (mean of residual), RE (relative error), RMSE (root mean square error), AIC (Akaike’s information criterion) and GMER (geometric mean error ratio) showed that the Saxton et al. (1986) method estimates the soil water retention curve better than the other methods.Key words: Pedotransfer function, soil texture, soil water retention curve
Genesis of Turbic Cryosols on north-facing slopes in a dissected, unglaciated landscape, west-central Yukon Territory
Authors: Smith C A.S. , Sanborn P T , Bond J D , Frank G
Published: March 2010

The characteristics and landscape distribution of Histic Dystric Turbic Cryosols were examined on a steep (>30%) northerly slope in the unglaciated Klondike Plateau, near Dawson City, Yukon Territory. Based on texture, major element geochemistry, and clay mineralogy, the mineral parent materials were crudely stratified, with a silty material of likely aeolian origin overlying sandy gravelly colluvium. Discontinuous organic matter-enriched horizons occurred 50 cm or more below the active layer, and contained abundant partially decomposed plant detritus. Eight accelerator radiocarbon dates, ranging from 350 ± 40 to 3680 ± 40 14C years BP, suggested that incorporation of organic materials within and below the active layer was geologically recent, and had likely occurred by a combination of cryoturbation and slope processes. The widespread and rapid initiation of mass movements on slopes containing permafrost that followed forest fires in 2004 on the Klondike Plateau may be an analogue for the processes that contributed to organic matter burial in these Cryosols. These soils may represent a significant reservoir of C, as similar sites occupy at least 15% of a representative portion of the Plateau. This reservoir may be vulnerable to mobilization if future climatic warming increases the frequency of forest fires and resulting slope instability.Key words: Tyrbic Cryosol, Yukon Territory, cryoturbation, soil organic carbon, mass movement
Crop response to nitrogen fertilizer: The delta yield concept
Authors: Kachanoski R G
Published: March 2010

Estimation of fertilizer N requirements of crops remains a challenge. Numerous field studies have been carried out to calibrate soil tests against yield response to applied fertilizer N. Synthesis and identification of common crop fertilizer N response across large data sets (years, sites) will allow maximum use of this past work and a framework for comparison of future work. The objective of this paper is to define macro-relationships between the economically optimum fertilizer N rate (EONR) and the yield increase at the EONR defined as the delta yield, ΔYec , for large data sets of 2nd- and 3rd-order estimates of fertilizer N response functions with both 0th and 1st-order rate relationships between fertilizer nitrogen use efficiency and applied fertilizer N. The derived macro-relationships are curvilinear, depend on the price ratio R = the ratio of the (price per kilogram of fertilizer N)/(price per kilogram grain), and are similar to measurements from data sets of corn fertilizer N response functions spanning decades (+20 yr) and representing areas in both the United States and Canada. The macro-relationships appear to be robust and therefore useful for quantifying (post-harvest analysis) soil fertility, crop fertilizer N requirement, and comparison/classification of N response functions.Key words: Response function, prediction, efficiency, economic N rate, corn
Soil mineral structural water loss during loss on ignition analyses
Authors: Sun H , Nelson M , Chen F , Husch J
Published: March 2010

Water loss from soil minerals has been known to cause errors in the determination of soil organic matter when the loss on ignition (LOI) method is used. Unfortunately, no known published studies reliably quantify the range of structural water in the soil. To do this, 15 common reference minerals were analyzed by LOI to obtain their individual water loss. In addition, 14 upland, loamy soil samples and 3 wetland/hydric soil samples with varied mineral contents were analyzed to collect their X-ray powder diffraction spectra. Based upon X-ray spectra peak intensities, the modal abundance of minerals in each soil sample was determined using the RockJock computer program. The resultant modal weight percentages of all identified minerals in each soil sample were then multiplied by the LOI value for each mineral to obtain the mineral structural water loss (SWL) of that soil sample. For the 17 soil samples analyzed, the range of mineral water loss is 0.56 to 2.45%. Depending on the LOI values of the soil samples, the SWL:LOI ratios range from 0.04 to around 1.00. The SWL:LOI ratios are particularly low for top wetland soil when the LOI value is higher. The ratios are lower for surface soil samples than for subsurface soil samples because of the high LOI values in surface soil samples. Understanding soil mineral water loss and its relation to the LOI patterns from various environments is important for the accurate evaluation of soil organic matter when the LOI method is used. Key words: Mineral, structural water, loss on ignition
Fractionnement de la fertilisation azotée dans la production du bleuet nain sauvage et suivi de l’azote du sol
Authors: Lafond J.
Published: March 2010

In wild lowbush blueberry production, fertilizers are applied in the spring of the vegetative year. To increase fertilizers efficiency and to reduce environmental losses, fertilizer split applications between vegetative and production year have been proposed. The objectives of this project were to determine the effect of split application of the nitrogen (N) in the vegetative and production year on the wild blueberry production and on soil mineral N in six blueberry fields located in Saguenay-Lac-Saint Jean (Quebec, Canada). Four rates of ammonium sulfate were applied in the spring of the vegetative year (0, 30, 60 and 90 kg ha-1). These same rates were applied in the spring of the vegetative (50%) and production (50%) years. The 30 kg N ha-1 rate was also applied only in the production year. For all sites, maximum fruit yields (3800 kg ha-1) were obtained with 62 kg N ha-1. However, the maximum rate ranged from 25 to 90 kg N ha-1 according to the sites. Applying N in the vegetative and production years had comparable fruits yields to those obtained with the fertilizer applied only in the vegetative year. One month after N application, the amount of N-NH4 in the soil profile increased by 4 to 38 kg ha-1 compared with the control. Split N application reduced by 55 to 76% the amount of NH4-N in soil layers only in the vegetative year. Soil nitrate increased with N rates at the end of the growing season, indicating that a part of NH4-N was nitrified and can be potentially leached the under root zone. According to the various maximum N rates obtained and N fertilizer impacts on soil N mineral, there would be no agronomic or environmental benefit to splitting low rates (<30 kg ha-1). However, with higher rates, splitting N between vegetation and production years would maximize fruit yields and reduce environmental risk.Key words: Maximum N rate, ammonium, nitrate, Vaccinium angustifolium Ait., split fertilization
The structure of Upper Mesopotamian cities: Insight from fluxgate gradiometer survey at Kazane Höyük, southeastern Turkey
Authors: Creekmore Andy
Published: March 2010

This paper presents the results of fluxgate gradiometer survey of the Bronze Age city at the site of Kazane Höyük, southeastern Turkey. We undertook this work to test the applicability of magnetometry to the study of the organization of urban space at this site within the context of urbanization in Upper Mesopotamia. Gradiometry collection covered a total of 37 520 m2 in five parts of the site. Results from each area were mixed but the most revealing data, from Area 1, show a roughly 2 ha area in the outer town that contains monumental, elite and administrative architecture as well as a main street. Low negative values indicate that most identified architecture is built with limestone foundations, and high positive values reveal that some of the buildings burned before their collapse. These interpretations are supported by excavations that reveal much about the use of the identified spaces and features. Although the structure of Area 1 is rectilinear, evidence for strict rules of city planning is lacking. Instead, the third millennium city at Kazane has a structure seen at other Upper Mesopotamian cities: dense, semi‐orthogonal architecture built along well‐maintained avenues. Combined with previous research, it is clear that Kazane contained multiple elite or administrative areas, which may indicate a degree of power‐sharing or heterarchy in the development and management of this city. Copyright © 2010 John Wiley & Sons, Ltd.
Interaction of eight HIV protease inhibitors with the canalicular efflux transporter ABCC2 (MRP2) in sandwich‐cultured rat and human hepatocytes
Authors: Ye Zhi‐wei , Camus Sandrine , Augustijns Patrick , Annaert Pieter
Published: March 2010

Hepatotoxicity has been reported as a side‐effect in some patients on HIV protease inhibitors (PI). Since transporter interaction has been implicated as a mechanism underlying drug‐mediated hepatotoxicity and drug–drug interactions, the interaction of PI with the hepatic canalicular efflux transporter ABCC2 (MRP2; multidrug resistance associated protein‐2) was studied. Interaction with ABCC2/Abcc2 was evaluated in human and rat sandwich‐cultured hepatocytes using 5(6)‐carboxy‐2′,7′‐dichlorofluorescein (CDF) as substrate. In rat hepatocytes, interaction with estradiol‐17‐β‐D‐glucuronide (E17G) efflux was also studied. In human hepatocytes, saquinavir, ritonavir and atazanavir were the most efficient inhibitors of ABCC2‐mediated biliary excretion of CDF, whereas in rat hepatocytes indinavir, lopinavir and nelfinavir were the most efficient. No species‐similarity was found for ABCC2/Abcc2 inhibition. In rat hepatocytes, the effects on Abcc2 were substrate‐dependent as inhibition of biliary excretion of E17G was most pronounced for saquinavir (completely blocked), amprenavir (82% inhibition) and indinavir (68% inhibition). In conclusion, several HIV PI showed substantial ABCC2 inhibition, which, combined with the effects of PI on other hepatobiliary disposition mechanisms, will determine the clinical relevance of thesein vitrointeraction data. Copyright © 2010 John Wiley & Sons, Ltd.