bluuebunny/crossref_metadata_2025 huggingface dataset:
Root penetration profiles of wheat and barley as affected by soil penetration resistance in field conditions
Authors: Martino Daniel L. , Shaykewich Carl F.
Published: April 2011

A study was conducted on three Manitoba soils (Marquette heavy clay, Fortier silty clay loam, and Souris loamy sand) with the objectives of: (a) assessing the effects of contrasting tillage systems on various soil physical properties; and (b) relating root penetration of cereals to these properties. The zero tillage (ZT) and conventional tillage (CT) treatments had been established between 3 (Marquette and Souris) and 10 (Fortier) years prior to the initiation of the study. Penetrometer resistance (PR), bulk density (BD) and pore size distribution (PSD) were measured at various depths and times during two growing seasons. The effects of tillage systems on soil properties were generally small, particularly in the poorly structured Souris loamy sand. PR in the top 10 cm of soil tended to be higher under ZT than under CT. PR varied markedly with time and was closely related to changes in soil water content. The proportion of macropores (> 100 μm in diameter) near the soil surface tended to be higher under ZT than under CT. There was no evidence of any detrimental effect of poor aeration on the final root penetration profiles of wheat. The proportion of roots penetrating the soil was inversely related to PR. Soil strength critical for root penetration was determined to be 2 MPa and was independent of soil type. In most situations, however, roots were able to grow into soil with mechanical impedance greater than 2 MPa, possibly by making use of biochannels and spatial and temporal heterogeneity in the soil structure. Key words: Wheat, barley, zero tillage, conventional tillage, root penetration, penetration resistance
Soil nitrate profile and response of potatoes to fertilizer N in relation to time of incorporation of lupin (Lupinus albus)
Authors: Sanderson J. B. , MacLeod J. A.
Published: April 2011

Lupin (Lupinus albus L. ’Ultra’) was evaluated as a green manure crop the year preceding potato production on Prince Edward Island for 3 yr. One pass of tandem disc was used to incorporate lupin green manure on 1 September (early) or 1 October (late). Barley residue following combine harvest was also incorporated in the same way in early September. One treatment of lupin was left unharvested with no fall incorporation (none), and in another treatment of lupin the seed was fall harvested with no fall incorporation. All treatments were moldboard plowed the following spring. Potato (Solanum tuberosum L. ’Russet Burbank’) was planted with three rates of nitrogen (0, 50, and 200 kg ha−1) band applied. Tuber yield and tuber N content increased with increasing rates of N applications in all incorporation treatments. Following late incorporated lupin, potato had higher tuber yield at 0 N than following the early incorporated lupin, while both treatments were higher than barley. Potato petiole nitrate-N levels and the mean spring nitrate-N concentrations in the soil were lower following barley than following lupin, and generally lower following early compared to late incorporation of lupin green manure. These data indicate the time of fall incorporation of a legume can have a significant effect on the N response of a succeeding crop. Early fall incorporation can result in significant fall N mineralization and winter leaching. Research on N response after legumes in rotation should consider the impact of time and method of residue incorporation. Key words: Petiole nitrate-N, nitrate leaching, green manure
The effect of tillage and KCl addition on pH, conductance, NO3-N, P, K and Cl distribution in the soil profile
Authors: Grant C. A. , Bailey L. D.
Published: April 2011

Distribution of NO3, P, K, Cl, pH and conductance through the soil profile were measured on two soil types after 4 yr of crop production using zero tillage (ZT) or conventional tillage (CT), with or without addition of KCl. All plots received N and P fertilizer each year as banded applications. Surface concentrations of NO3-N were higher under ZT than CT, particularly on the fine sandy loam soil. Accumulation of NO3-N also occurred in the 60- to 120-cm zone, under both tillage systems in both soils. Carryover of NO3-N was substantially greater on the silty clay than the fine sandy loam soil. Phosphate accumulated at the depth of band application in both soils under both tillage systems. Potassium concentration was generally higher under ZT than CT in the surface 15 cm of both soils, presumably due to surface retention of K from fertilizer applications and crop residues. Chloride was higher under ZT than CT in the surface 5 cm of both soils, but was higher under CT than ZT in the 30- to 60-cm and 60- to 120-cm depths in the silty clay soil, if KCl had been applied. The pH on both soils under both tillage systems was reduced in the 10- to 12.5-cm soil depth, corresponding to the zone of fertilizer application. On the silty clay soil, pH was higher under ZT than CT in the 10- to 15-cm depth and tended to be higher under ZT than CT at all depths below 15 cm. Conductance was not influenced by tillage in either soil. Application of KCl increased K and Cl concentrations in the surface 15 cm on both soils. Concentration of Cl was increased to 120 cm in both soils, indicating the mobility and leaching potential of this anion. Conductance and pH were increased in the 2.5- to 5.0-cm and 10- to 12.5-cm depths by KCl application in the fine sandy loam soil, but on the silty clay soil, only conductance was increased. Key words: Zero tillage, nutrient stratification, pH stratification
Nitrate-N, ammonium-N, and organic matter in relation to profile characteristics of Dark Brown Chernozemic soils
Authors: Beke G. J. , Graham D. P. , Entz T.
Published: April 2011

Thirty-six deep soil profiles (3.3 m) from a 32-ha irrigated field in southern Alberta were evaluated to determine the relationship between pedogenic development and nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), and organic matter (OM) content and distribution. The soils were classified into three fine-loamy Dark Brown subgroups. Three classes of solum thickness and slope position were identified. The NO3-N, NH4-N, and OM content in the 3.3-m profile, and below the solum, the control section, and the 1.2-m rooting depth were compared and correlation analyses were conducted between these properties and properties of the saturation extract.The OM content decreased exponentially with increase in profile depth, but the NO3-N and, to some extent, the NH4-N contents varied according to solum thickness regardless of subgroup classification. On average, soils with a thin (< 35 cm) or thick (> 75 cm) solum had a zone of high NO3-N concentration between the 100- and 150-cm depths. This was ascribed to less favorable soil moisture conditions for crop growth on the thin-solum soils and probably more frequent leaching events in the thick-solum soils. Distinctly different correlation coefficients between NO3-N, NH4-N, and OM and the saturation extract properties of the control section supported the series designations of the solum-thickness separations. Solum thickness and topographic position should be considered when applying nitrogen fertilizers or irrigations. Key words: Semiarid region, intermittent irrigation, Chernozemic soils, nitrate-N, ammonium-N, organic matter
Soil genesis on a chronosequence, Pinery Provincial Park, Ontario
Authors: VandenBygaart A. J. , Protz R.
Published: April 2011

Soils on a late Holocene dune chronosequence were studied along Lake Huron at Pinery Provincial Park, in southwestern Ontario. Progressive exposure of new materials, associated with declining lake levels, has allowed the development of soils in a sequential manner from the shoreline (approximately time zero) to about 2.3 km inland. Six soil pits were excavated and sampled in narrow depth increments along a transect ranging in estimated age from 100 to 4700 yr B.P. Chronofunctions were formulated based on pedogenic properties in order to evaluate the rates and pathways of soil genesis in southern Ontario. The soils graded from an Orthic Regosol near the shore to an Eluviated Dystric Brunisol to 2.3 km inland. The increasing thickness of the solum and darker chroma in the B horizons were the most obvious morphological indications of a progression in soil weathering. Linear chronofunctions of increasing total silt and clay contents with soil age suggest that physical breakdown of sand particles to silt and clay may be occurring. Total organic matter in the profiles increases logarithmically with soil age with a rapid increase in the first 2000 yr or so. The depth of CaCO3 leaching increased linearly with increasing soil age. Data indicate that mean annual precipitation may be the most important influence on the rates of carbonate weathering. Soil pH decreases linearly with soil age in the first 2900 yr. However, vegetative variations appear to influence the pH beyond 2900 yr of soil development. Depth to, and thickness of, the B horizons also increased linearly with soil age. Key words: CaCO3 weathering, solum thickness, clay accumulation, dune chronosequence
Rotation, tillage and seeder effects on winter wheat performance and soil moisture regime
Authors: Lindwall C. W. , Larney F. J. , Carefoot J. M.
Published: April 2011

The optimum management system for winter wheat (Triticum aestivum L.) production in southern Alberta has not been adequately defined. A 9-yr (1978–1986) study was conducted to determine the effects of three rotations (continuous winter wheat, winter wheat–fallow and winter wheat–barley (Hordeum vulgare L.)–fallow), two tillage systems (conventional tillage, zero tillage) and two seeder types (hoe-drill, disc drill) on winter wheat growth, yield and water use. Continuous cropping to winter wheat was terminated after 4 yr because of a heavy downy brome (Bromus tectorum L.) infestation. Soil moisture reserves to 1.5-m depth fell to only 61% of that under the wheat–fallow rotation. Wheat grown in the wheat–barley–fallow rotation yielded on average 4% higher than that in the wheat–fallow rotation. Yields under zero tillage were significantly higher in 3 of the 9 study years, and slightly higher in 5 yr, due to better soil moisture conservation once the zero-tillage treatment was established for 2 yr. Zero tillage was most beneficial when precipitation at fall planting was less than normal. The hoe-drill provided more effective seed placement than the disc drill when surface soil conditions were dry at or soon after seeding. A management system which incorporates zero tillage (and preferably seeding with a hoe drill) into a 3-yr (wheat–barley–fallow) rotation is best suited for winter wheat production in southern Alberta. Key words: Wheat (winter), crop rotation, zero tillage, seed drill, soil moisture regime
Kinetics of monoammonium phosphate-induced potassium release from selected soils
Authors: Zhou J. M. , Huang P. M.
Published: April 2011

When monoammonium phosphate fertilizer is applied to soils, the phosphate concentration is very high and the pH is quite low in the immediate vicinity of the fertilizer granule. In this study, the release of potassium (K) by 1 M NH4H2PO4 solution at pH 4.0 from three Chinese soils, Oxisol, Alfisol and Entisol, was investigated. The results showed that NH4H2PO4 promoted K release from these soils. The NH4H2PO4-induced K release obeyed the zero-order kinetics; the release-rate coefficients from these soils at 25 °C ranged from 72 to 170 μg K kg−1 h−1, much higher than observed (4–37 μg kg−1 h−1) in 1 M NH4Cl at pH 4.0. The combined effect of phosphate and proton on the alteration of K-bearing minerals was evidently the major mechanism of the NH4H2PO4-induced K release from the soils. The data indicated that the application of NH4H2PO4 fertilizer may enhance the rate of K supply in soils and lead to the conversion of some of N and P in the fertilizer to a slowly available form in soils because of the formation of a crystalline reaction product, ammonium taranakite. Key words: Potassium dynamics, phosphate application, ammonium taranakite
Weathering of clay minerals induced by fluoride-containing solutions from phosphogypsum by-product
Authors: Arocena J. M. , Dudas M. J. , Poulsen L. , Rutherford P. M.
Published: April 2011

The production of phosphate fertilizer from phosphate rock results in the formation of phosphogypsum (PG) and HF. Soluble F− ends up in process water and in the pore space of the PG by-product. This study determined changes in the amount, properties and mineral composition of soil clay upon reaction with acidic PG solutions. Calcareous and non calcareous soils were reacted with PG leachates (PG-L, 30 mg F− L−1) and process water (PG-PW, 6070 mg F− L−1) using a sequential batch equilibration method. Phosphogypsum-L did not alter the clay fraction as much as PG-PW, which dissolved as much as two-thirds of the clay fraction. Phosphogypsum-PW reduced surface area of clay fractions from about 500 to 150 m2 g−1; Cation exchange capacity CEC was decreased from about 60 to 17 cmolc kg−1 clay. Reduction in surface area and CEC in PG-PW treated soil corresponded to near complete dissolution of smectite and a negative enrichment of mica. Kaolinite in coarse clay of the PG-PW treatment was reduced to 20% of the control and was completely destroyed in fine clay fractions. Amorphous silica was produced from the F−-induced dissolution of clay. The results indicate there is likely to be considerable alteration of minerals in subsoils beneath PG waste repositories and of clay liners used at some storage facilities. Key words: Clay liners, landfills, dissolution, waste management, leachates, geochemical reactions, mineral stability
Carbon kinetics in a Black Chernozem with roots in situ
Authors: Xu J. G. , Juma N. G.
Published: April 2011

The rates of decomposition of roots and root-derived materials are needed to assess the contribution of these materials to sequestration of organic carbon in soil. The objective of this study was to examine the kinetics of different forms of C in a Black Chernozem, with roots in situ under two barley cultivars, using 14C pulse-labeling and incubation methods. Plants were pulse-labeled (1 d) with 14CO2 25 d after emergence. Shoots were excised, and undisturbed soil cores containing the roots of a single plant were incubated at 20 °C for 80 d. The experiment involved two barley cultivars, with six replications at six sampling dates (days 0, 5, 10, 25, 40 and 80). The percentage of the labile components in roots of Abee (48%) was greater than that of Samson (39%), but the half lives of the labile components (0.693 k−1) of the roots were not significantly different between the two barley cultivars. The decomposition-rate constants for the resistant components of the roots were also not significantly different between the two barley cultivars. This indicated that the difference between the two barley cultivars in root decomposition rate could be explained by the difference in the ratios of the labile components to the resistant components. The average half life of 14C in roots was 41 d for Abee and 71 d for Samson. The amount of root 14C + soil 14C under Samson was higher than under Abee during the incubation period. These results supported our hypothesis that the cultivar that translocated more 14C-labeled carbon into roots and root-derived material has greater microbial respiration and greater C stabilization because a portion of added C remains in the soil after being transformed by microorganisms. Key words: Carbon kinetics, carbon sequestration, roots in situ, 14C pulse-labeling, Black Chernozem
SHORT COMMUNICATION: Soil chemical changes associated with NP-fertigated and drip irrigated high-density apple orchards
Authors: Neilsen G. H. , Hoyt P. B. , Neilsen D.
Published: April 2011

Soil was sampled in 20 high-density apple (Malus domestica Borkh.) orchards which had generally been NP-fertigated using drip irrigation for the 2–5 yr since their establishment. Soil chemical changes including decreases in pH, extractable Ca, Mg, K, S and B and increases in extractable Cu, Mn and Fe were measurable, often within 2 yr. Leaf nutrient concentrations below deficiency levels were widespread for B and Zn and in a few cases, also occurred for Mg and K. Key words: Fertigation, soil chemical degradation, apple, drip irrigation
The Influence of dairy manure on atrazine and 2,4-dichlorophenoxyacetic acid mineralization in pasture soils
Authors: Entry James A. , Emmingham William H.
Published: April 2011

The influence of manure application to pasture soils on bacterial and fungal biomass and the atrazine (2 chloro-4 [ethylamino]-6[isopropylamino]-s-triazine) and 2,4-D (2,4 dichlorophenoxyacetic acid) mineralization was assessed in microcosms using radiometric techniques. Additions of 5 tonnes manure ha−1 yr−1 were made to three pasture soils over 20 yr in western Oregon at a rate of 0.42 t ha−1 each month. No manure or fertilizer was added to control treatments. We found greater amounts of total fungal and bacterial biomass in soils that received added manure. There were no differences among active bacterial and fungal biomass between pasture soils that received manure application and pasture soils that received no manure. Greater amounts of atrazine and 2,4-D were mineralized when manure was applied than when soil received no manure or fertilizer. Greater amounts of atrazine and 2,4-D were mineralized in the spring than in summer, fall or winter. Results of this study indicate that the application of dairy manure to pasture soils will significantly increase herbicide degradation rates. Key words: Pasture soils, microbial biomass, manure application, atrazine, 2,4-D, herbicide mineralization
SHORT COMMUNICATION: Lime-amended acid soil has elevated pH 30 years later
Authors: Beckie H. J. , Ukrainetz H.
Published: April 2011

Lime-amended acid soil (a single application in 1963 at rates of 4.5 and 6.7 t ha−1) at Scott, Saskatchewan had pH of 0.5 and 1.1 units higher, respectively, than unlimed soil, when measured more than 30 yr later in 1994. However, no differences in soil-available phosphorus levels and crop yield were detected. Key words: Soil acidity, lime, phosphorus, Brassica rapa L., Triticum aestivum L.
Assessing plant-available potassium in soil using cation exchange membrane burial
Authors: Qian P. , Schoenau J. J. , Greer K. J. , Liu Z.
Published: April 2011

We assessed a method for extraction of plant-available potassium using a cation exchange membrane (CEM) burial technique. The study compared the amounts of K extracted by CEM burial with three reference chemical-based extractants for 19 soil samples representing a wide range of soil types in Saskatchewan, Canada and the People’s Republic of China. The three reference extractants were (1) 1 M NH4OAc, (2) a mixed solution of 0.01 M EDTA, 0.25 M NaHCO3 and 0.01 M NH4F and (3) 1 M HNO3. Potassium extractable by 1 M NH4OAc ranged from 37 mg kg−1 to 1889 mg kg−1 among the 19 soils. The K availability as predicted by CEM was significantly correlated with the reference methods with the strongest relationship (r2 = 0.94, P < 0.001) with the EDTA-NH4F test. To evaluate the relative ability of CEM and the conventional tests to predict K availability to plants, canola and wheat were grown on the 19 soils in the growth chamber and plant K uptake was compared with test-predicted K availability. All test methods revealed a similar ability to predict K availability with good correlation (r2 = 0.70, P < 0.001) with plant uptake. However, the CEM method showed its advantages in predicting plant availability in a variety of soil types with large coefficients of determination in both acidic and neutral to alkaline soil groupings. The CEM burial technique could be readily adopted in soil K availability analysis because of low cost and simplicity as well as its consistency over a wide range of soil types. Key words: Cation exchange membrane, burial technique, extraction, plant K availability, plant K uptake, soil test
Usage of soil moisture models in agronomic research
Authors: Akinremi O. O. , McGinn S. M.
Published: April 2011

Soil moisture controls many important processes in the soil-plant system and the extent of these processes cannot be quantified without knowing moisture status of the root zone. Of agronomic importance these include, seedling emergence, evapotranspiration, mineralization of the soil organic fraction, surface runoff, leaching and crop yield. Many models have been developed to simulate these processes based on algorithms of varying degrees of complexity that describe the dynamic nature of soil moisture at different temporal and spatial scales. This paper reviews the direct applications of soil moisture models in agronomy from the field to regional scale and for daily to seasonal time steps. At every level of detail, the lack of model validation beyond the region where it was developed is the main limitation to the application of soil moisture models in agronomy. At the field scale, models have been used for irrigation scheduling to ensure efficient utilization of irrigation water and maximize crop yields. Models are also used to estimate crop yield based on the growing season water use. The water use of crops is converted to biomass accumulation and grain yield using a water-use efficiency coefficient and a harvest index. Other empirical equations are available that relate cumulative crop water use directly to grain yield. On a regional scale, in a study of drought climatology on the Canadian prairie, we coupled a soil water model, the Versatile Soil Moisture Budget, with the Palmer Drought Index model to improve the modelling of soil moisture. This was found to improve the relationship of the Palmer drought index to wheat yield reduction resulting from drought. Key words: Soil moisture, modelling, water-use, evapotranspiration, aridity index, Canadian prairies
First- and second-generation agrometeorological models for the prairies and simulated water-demand for potatoes
Authors: Raddatz R. L. , Ash G. H. B. , Shaykewich C. F. , Roberge K. A. , Graham J. L.
Published: April 2011

On the Canadian prairies, moisture is usually the limiting factor in crop production. Occasionally, the thermal regime limits yields. At the Winnipeg Climate Centre, Environment Canada, a root-zone water-balance model simulates crop development, water-demand and water-use with daily climatological observations from across the agricultural portion of the Canadian Prairie Provinces. Simulations are used for regional-scale monitoring of the prairie’s major crops (spring wheat, barley and canola) and they have been used to quantify climatological risks. This agrometeorological model is termed a first-generation model as potential evapotranspiration is estimated empirically from Baier and Robertson’s simplest regression equation.A coupled atmosphere-crop-soil agrometeorological model has also been developed for crop monitoring on the prairies. This model generates atmospheric boundary layer profiles at climatological-sites using upper-air analyses and surface characteristics. The crop-soil boundary layer consists of the growing crop, and the top, root and sub-zones of the soil. Evapotranspiration is calculated deterministically from the air’s water vapour density deficit. The calculation is modulated by aerodynamic, canopy and soil resistances. The coupled approach is termed a second-generation model.The re-formulation of the coupled model to simulate the phenology and water-demand of a newly significant crop, potatoes, is described. Comparison with 1994 and 1995 test-plot observations of fractional leaf area and rooting depth suggests that the potato phenology simulation requires further development. Estimates of daily crop water-demand are similar but show greater day-today variation than values generated by a first-generation Baier and Robertson procedure. Key words: Regional modelling, soil moisture, phenology, crop water-demand, potatoes
Field measurement of soil moisture using neutron probes
Authors: Chanasyk D. S. , Naeth M. A.
Published: April 2011

Soil moisture measurements are critical to all field studies of soil-plant-water relationships. Dependable and reliable techniques are required to provide such measurements. Neutron probes were developed more than 40 years ago and continue to be used today. They offer many advantages as a measurement technique, the most important of which is non-destructive, repetitive measurements of soil moisture. Much research has been focused on overcoming the two major limitations of neutron probes: measuring near-surface soil moisture and a smoothing of moisture data at sharp moisture discontinuities in the soil. Various techniques have been devised to overcome the first limitation and the error associated with the second is acceptable by probe users The dramatic decline in the number of articles in the scientific literature related to neutron probes during the past decade is likely an indication that neutron probe technology has matured and that neutron probes have become accepted as a reliable and dependable field technique for soil moisture measurement. Key words: Neutron probe, soil moisture, water budget
Response of silage corn and wheat to dairy manure and fertilizers in long-term fertilized and manured trials
Authors: N’Dayegamiye Adrien
Published: April 2011

Silage corn (Zea mays L.) and wheat (Triticum aestivum L.) were grown (1987–1991) in trials that had been manured and fertilized since 1978 to evaluate the effects of annual N, P, K and Mg fertilizers and dairy cattle manure on yields and nutrient uptake. Manure as the main factor was applied at 0 and 20 Mg ha−1 on a wet-weight basis. The subplots consisted of six fertilizer treatments: NK, PK, NP, NPK, NPKMg and the unfertilized control. For silage corn, fertilizer rates were 150, 100, 150 and 40 kg ha−1 N, P2O5, K2O and Mg, respectively. Fertilizer rates for wheat were 80, 100, 120 and 40 kg ha−1 N, P2O5, K2O and Mg, respectively. In manured plots, reduced N rates were applied for silage corn (100 kg N ha−1) and wheat (50 kg N ha−1). Silage corn and wheat yields and nutrient uptake were significantly increased by manure, N and K fertilizers whereas P and Mg effects were limited. A N-K synergistic effect on yields and nutrient uptake was observed both for silage corn and wheat. Application of K fertilizer significantly reduced silage corn Mg uptake without limiting yields, while it increased wheat yields and Mg uptake. Reduced N rates applied to silage corn and wheat achieved maximum yields and nutrient uptake in long-term manured treatments. Crop response to fertilizer application varied with crop species and was higher for silage corn than for wheat. Fertilizer adjustment is necessary after a long-term fertilizer or manure application. Key words: Silage corn, wheat, yields, nutrient uptake, manure, fertilizers, long-term, response to fertilizers
Water-stable aggregation and organic matter in four soils under conventional and zero tillage
Authors: Franzluebbers A. J. , Arshad M. A.
Published: April 2011

Zero tillage management reduces soil exposure and disturbance and, therefore, may improve soil aggregation and organic matter sequestration under some environments. We determined the distribution and soil organic C (SOC) content of five water-stable aggregate (WSA) classes at depths of 0–50, 50–125 and 125–200 mm in a loam, a slit loam, a clay loam, and a clay soil managed for 4–16 yr under conventional shallow tillage (CT) and zero tillage (ZT) in the Peace River region of northern Alberta and British Columbia. Macroaggregation (> 0.25 mm and mean weight diameter (MWD) were greater under ZT than under CT in coarse-textured soils at a depth of 0–125 mm. Under CT, macroaggregation and MWD increased with increasing clay content, thereby reducing the potential of ZT to improve these properties in soils with high clay content. Concentration of SOC tended to be greatest in macroaggregates and lowest in microaggregates of coarse-textured soils, but was not different among WSA classes of fine-textured soils. Soil organic C content of macroaggregates under ZT was 0.34, 0.40, 0.62, and 0.16 kg m−2 greater than under CT at a depth of 0–200 mm in the loam, silt loam, clay loam and clay soil, respectively. Our results suggest that implementation of ZT in this cold semiarid climate can quickly improve WSA of coarse-textured soils and potentially increase SOC sequestration, albeit more slowly than in warmer more humid climates, when macroaggregation is improved. Key words: Aggregation, soil organic matter, soil texture, tillage
Effects of biopores on the growth and N-uptake of wheat at three levels of soil moisture
Authors: Volkmar K. M.
Published: April 2011

Roots grow more rapidly through soil spaces such as vacated root channels than through undisturbed soil. This experiment was conducted to determine the extent to which transfer of nutrients is compromised by gaps between the pore wall and the root. Undisturbed cores were obtained from a no-till Dark Brown Chernozemic soil. The cores were divided into three 2.5-cm-thick segments (3.8–6.3 cm, 7.8–10.3 cm, and 11.75–14.25 cm soil layers). The density of 200–500 μm (P200) and 500–1000 μm (P500) diameter pores was visually assessed in each segment. The cores were adjusted to water potentials of − 0.01, − 0.1 and − 1.5 MPa by adding K15NO3-labelled water. Pots containing wheat (Triticum aestivum) plants were placed on top of the cores and the number of roots that appeared at the bottom of the cores, the root length within the cores, and shoot 15N content were measured after 72 h. Small pore (P200) density had no effect on root number at any moisture level. Large pore (P500) density correlated positively with root number at − 0.10 MPa (r2 = 0.57) and − 1.5 Mpa (r2 = 0.68). The equation relating shoot 15N content and root number had a common slope across all moisture treatments, suggesting that the rates of N-uptake per unit root were not compromised by macropore-assisted root growth at the investigated moisture levels. It is unclear if uptake is directly across the pore or via laterals growing outside the pore wall. N-uptake per unit root length of roots growing through soil pores may be compromised at moderate levels of soil moisture. Key words: Biopores, macroporosity, N-uptake, nitrogen, penetrometer resistance, root growth
SHORT COMMUNICATION: Elemental content of animal licks along the eastern slopes of the Rocky Mountains in southern Alberta, Canada
Authors: Dormaar J. F. , Walker B. D.
Published: April 2011

A number of animal licks, representing dry earth exposures, muck licks, and rock face licks, were sampled and analysed for 12 elements by using a sulphuric acid-hydrogen peroxide method to simulate digesta. The various types of licks may serve different needs. Sodium, magnesium, manganese, iron, and copper may draw animals to specific sites. Key words: Salt licks, ungulates, landscape management, Rocky Mountains
Modeling nitrogen and phosphorus interactions in intensively managed nursery soil-plant systems
Authors: Teng Yuanxin , Timmer Victor R.
Published: April 2011

Modeling simultaneous response to multinutrient fertilization to take advantage of element interactions is a promising approach in fertilizer prescription, but the practice is relatively unexplored in forestry applications. This paper demonstrates that simultaneous prescription of nitrogen (N) and phosphorus (P) fertilizer for tree seedling culture can be facilitated by response surface models generated from a multi-level factorial experiment designed to quantify growth, nutritional response and N × P interactions in white spruce [Picea glauca (Moench) Voss]. Seedlings grown from seeds in potted soil were tested in a 6 (N) × 4 (P) × 3 (replicates) factorial experiment in a greenhouse. Analysis of variance indicated significant quadratic trends in treatment responses and significant N × P interactions, hence quadratic response surface models were generated from the total biomass database. However, model accuracy (R2 = 0.56) was low and the N × P interaction was underestimated when luxury to toxic N levels were included. Since the positive N × P interaction was enhanced by N additions at lower (deficient) levels but diminished at higher (luxury to toxic) levels, a model constructed from a data subset which excluded high N treatments markedly improved accuracy (R2 = 0.88) and significantly increased the regression-coefficient estimate for the interaction term. Verification in a nursery field trial for a 3-yr rotation confirmed that this refined model improved fertilizer prescription by increasing acceptable seedling numbers and fertilizer recovery by plants in bare-root stock production. Key words: Nutrient interaction, modeling, forest nursery, fertilization efficiency
Yield stability indices of primocane-fruiting red raspberry (Rubus idaeus L.)
Authors: Sullivan J. A. , Privé J. P.
Published: April 2011

Three primocane-fruiting cultivars were grown over 14 location/years (environments) to assess their relative yield stability using three different statistical models. The models varied in their definition of stability and sometimes produced conflicting results. In general, ranking of the three cultivars from most to least stable was Heritage, Redwing and Autumn Bliss. Although Redwing and Autumn Bliss had better productivity than Heritage, both cultivars had a large portion of genotype × environment variance attributed to unpredictable elements according to some stability analyses. This variation was characterized by large and significant deviations from linearity. No single model adequately characterized stability in these cultivars. The three cultivars varied in productivity across the 14 environments, with Heritage always yielding less than the two other cultivars. Key words: Breeding, fall-bearing, genotype × environment, yield stability
Survey of yield losses due to weeds in central Alberta
Authors: Neil Harker K.
Published: April 2011

Weedy and weed-free yields were determined in fields of barley, canola, and peas in Lacombe County, Alberta, Canada from 1995 to 1997. Yield losses were most frequent and severe in peas, and least frequent and less severe in barley. Yield losses due to weed competition were not detectable at 33, 60, and 73% of the pea, canola, and barley sites, respectively. Key words: Competition, interference, barley, canola, peas
Response of cucumber to timing of fertilizer application in southwest Nigeria
Authors: Odeleye F. O. , Odeleye O. M. O. , Vessey J. K. , Dong Z. , Ebuzome H. N.
Published: April 2011

A field trial was conducted at the experimental farm of the Department of Crop Protection and Environmental Biology, University of Ibadan, Nigeria, to determine the growth and yield response of cucumber (cv. Poinsett) to timing of fertilizer application. Fertilizer (20:10:10), at the rate of 150 kg N ha-1, was applied at: planting, 3 weeks after planting (WAP) and 6 WAP. Similarly, split applications were given at planting + 3 WAP, at planting + 6 WAP and at 3 WAP + 6 WAP. The experimental design was a randomized complete block with seven treatments (six fertilizer application treatments plus a non fertilizer control) and four replications. Means were separated using Duncan’s Multiple Range Test at the 5% level of significance. In general, plants that were fertilized performed better than control plants in terms of vegetative growth and yield. A split application at 3 WAP + 6 WAP performed the best in terms of vegetative growth and fruit yield. Fertilizer applied once-over at 6 WAP was the least beneficial; application of fertilizer once-over at planting, or a split application at planting + 3 WAP, resulted in a high level of vegetative growth but lower fruit yield compared with the split application at 3 WAP + 6 WAP. Key words: Cucumber, N-P-K., time of application, vegetative growth, fruit yield
When is short-season soybean most susceptible to water stress?
Authors: Morrison M. J. , McLaughlin N. B. , Cober E. R. , Butler G. M.
Published: April 2011

Fourteen soybean (Glycine max L. Merr.) cultivars were grown at Ottawa from 1993 to 2004 in a replicated design. Phenology, yield and seed quality data were collected. Climate data were merged into the data set. Seven key phenological growth stages were identified and the total precipitation (ppt) between stages was calculated per cultivar for all possible durations. Mean cumulative ppt among the growth stage durations was correlated with mean seed yield, 1000-seed weight (tsw) seed protein and oil content. Variation in ppt prior to flowering did not influence yield. Yield and tsw were found to be most susceptible to water stress from flowering to the end of seed development. The most sensitive stage occurred during a period from the beginning to the end of pod development (R4 to mid R5). Seed protein was correlated with ppt from the beginning of flowering to the beginning of seed development. Seed oil content was reduced by late season precipitation. The identification of the most sensitive stage of development in soybean to water stress will be useful for producers forecasting yield response to precipitation and for plant breeders targeting selection for water stress tolerance. Key words: Water stress, soybean, Glycine max L. Merr.
OAC Bright birdsfoot trefoil
Authors: Twamley B. E. , Tomes D. T. , Bowley S. R.
Published: April 2011

OAC Bright is a birdsfoot trefoil (Lotus corniculatus L.) cultivar developed by the Crop Science Department, University of Guelph. It was developed by within and among half-sib progeny recurrent selection for seedling vigour and seed yield. OAC Bright has 2% higher seedling vigour and 0.8% higher herbage yield than Leo. It has similar maturity and persistence to Leo. Key words: Birdsfoot trefoil, cultivar description, seedling vigour, seed yield, recurrent selection
9063 soybean
Authors: Voldeng H. D. , Guillemette R. J. D. , Leonard D. A. , Cober E. R.
Published: April 2011

9063 is a 2750 crop heat unit soybean [Glycine max (L.) Merr.] cultivar with good yield potential. Key words: Soybean, cultivar description
N credit of soybean to a following corn crop in central Ontario
Authors: Ding Wu , Hume D. J. , Vyn T. J. , Beauchamp E. G.
Published: April 2011

Field studies were conducted to determine the nitrogen (N) fertilizer replacement value (NFRV) when soybean (Glycine max [L.] Merrill) preceded corn (Zea mays L.) in the rotation (S-C), compared to corn preceding corn (C-C). Large, replicated blocks of soybean and corn were established in 1993 and 1994 near Elora, Ontario. In the following year, each large block was subdivided into smaller plots. Fertilizer N was applied at six rates from 0 to 200 kg N ha−1 to the second-year corn crop. Corn grain yield responses to fertilizer N were fitted by quadratic regression. Maximum economic rate of N was calculated for each crop sequence and NFRV's were determined. Corn yields were consistently higher when grown after soybean (S-C) than after corn (C-C). Maximum corn yields were 10.4 and 12.3 Mg ha−1 in 1994 and 1995, respectively. NFRVs for S-C, compared to C-C, were 41 and 59 kg N ha−1 in the two years. As a result of these studies and numerous other experiments, recommended fertilizer N rates have been changed to 30 kg N ha−1 less for S-C than for C-C in central Ontario. Key words: Nitrogen credit, corn, soybean, fertilizer N, replacement value, crop rotation
Morphogenetic characteristics of timothy grown with varying N nutrition
Authors: Bélanger G.
Published: April 2011

The leaf area development of grasses and subsequently radiation interception depends on morphogenetic processes such as leaf extension and appearance. Leaf extension and appearance of timothy (Phleum pratense L.) grown with varying rates of N nutrition and their impact on sward structural characteristics were studied during primary growth in spring and during a summer regrowth. With no N applied in spring and summer, the leaf extension rate (LER) and the leaf appearance rate (LAR) of timothy were approximately 40% and 65% of that obtained under non-limiting N conditions (140 kg N ha−1 in spring and 120 kg N ha−1 in summer). Nitrogen deficiency reduced tiller density in spring but increased it in summer. The differential effect of the N deficiency on LER and LAR modified the sward structural characteristics. Nitrogen deficiency decreased the length of mature leaves, their width and the total leaf length per tiller. The reduced LER associated with N deficiency explained for the most part the N effect on leaf area expansion and radiation interception. Key words: Phleum pratense L., timothy, leaf extension, leaf appearance, tillering, nitrogen
Response to weed control by four spring wheat genotypes differing in competitive ability
Authors: Hucl P.
Published: April 2011

Increased crop competitiveness may complement existing weed control methods. The objective of this research was to establish whether spring wheat (Triticum aestivum L.) genotypes with contrasting competitive abilities respond differently to weed control levels. Four sibling genotypes differing in competitive ability were grown under simulated weedy conditions and subjected to four weed control levels. The competitive genotypes were superior to the less-competitive genotypes in grain yield under weedy and partially weedy conditions. Key words: Triticum aestivum L., competition, weed control, genotype × weedcontrol interaction
Effect of orchard cover crop on incidence of low-temperature-basidiomycete rot of stored Spartan Apples
Authors: Sholberg P. L. , Hogue E. J. , Neilsen G.H.
Published: April 2011

Apples cv. Spartan from the same orchard block in Kelowna, British Columbia, were stored in a controlled atmosphere storage facility for seven to eight months each year for a period of four years from 1989 to 1993 to study the effect of nitrogen fertilization rate and orchard cover crop on the incidence of low-temperature-basidiomycete (LTB) rot. The effect of adding orchard floor litter from the cover crop was studied during the last two years of the study. Rate of nitrogen fertilization did not affect disease incidence, but cover crop influenced LTB rot in apples stored with and without orchard floor litter. White clover litter placed in apple bags from the treatment of white clover with a clean strip on the tree row resulted in 12.8% LTB rot and was significantly higher than the mixed grass treatments. The effect was not as clear for apples stored without the addition of litter, although apples from the white clover cover had a higher incidence of LTB rot than apples from the clean orchard cover. Sterilizing the orchard litter by autoclaving reduced the incidence of LTB rot compared with nonautoclaved litter, and apples stored without litter had an even lower incidence of LTB rot. Isolations from symptomatic fruit in 1992 showed that 86% of the isolates were pathogenic and caused LTB rot. Spartan apples were infected early during fruit development, because 17.2% of the apples were infected by 23 June in 1993. In the orchard, Spartlett pear was more susceptible to LTB infection than Spartan apple. The use of cover crop management for reducing the incidence of LTB rot is discussed. Key words: Coprinus rot, postharvest, storage, control, pest management
Soil and alfalfa response after amelioration of subsoil acidity in a fine sandy loam Podzol in Prince Edward Island
Authors: Carter M. R. , Richards J. E.
Published: April 2011

Subsoils in Prince Edward Island have poor chemical and often physical quality for root growth that may present a barrier to development of alfalfa (Medicago sativa L.). This study was conducted to characterise the response or benefit, on soil properties and alfalfa growth, of chemical amelioration and loosening of the subsoil. In 1987, the following three treatments were imposed on an acidic, fine sandy loam, Humo-Ferric Podzol: control (no subsoiling or lime), subsoiling alone, and subsoiling plus lime (5 Mg ha−1 dry CaCO3) mixed into the subsoil. The subsoiler was a Wye Double-Digger, a combined plough and rotary cultivator that facilitated the mixing of lime into the soil over the 230–480 mm depth. Management of the 0–200 mm soil depth was the same for all treatments. Growth of alfalfa and change in soil properties were monitored over time. In 2 of 4 yr (1991–1994), alfalfa yield was significantly (P < 0.05) increased by the subsoil plus lime treatment, compared with subsoiling alone or the control. Yield increases were related to periods of low growing season precipitation. Subsoil amelioration increased alfalfa root penetration (by 90 mm) and reduced leaf Mn concentration. Over an 8-yr period (1987–1994), soil exchangeable Ca was increased over fourfold, while exchangeable Al was decreased threefold in the ameliorated subsoil, compared with the control. Soil pH (in water) was increased from 4.8 to near 6.0. There was some evidence that liming of the topsoil improved the subsoil chemistry over time. Bulk density and penetrometer resistance contours, measured over time, indicated that the soil loosening effect was sustained throughout the soil profile over the duration of the study. Soil biological properties were not changed by the subsoil treatments. Key words: Subsoil acidity, podzol, lime, deep placement, alfalfa (Medicago sativa L.), cool-humid climate
Effect of organic carbon (peat) on moisture retention of peat:mineral mixes
Authors: Moskal T D , Leskiw L. , Naeth M A , Chanasyk D S
Published: April 2011

Quantification of the effects of organic carbon (OC) addition to reclaimed soils is an important reclamation issue. Such effects on soil texture, field capacity (FC), wilting point (PWP) and water-holding capacity (WHC), all expressed both on a gravimetric and volumetric basis, were quantified using both in situ soil samples and laboratory-prepared peat:mineral mixes. Soil samples were collected from both natural and reclaimed areas within the Oil Sands region of Alberta; peat was obtained from the same area. Organic carbon was determined for laboratory-created mixtures and expressed as volume ratios; for the in situ samples it was expressed as % OC. Bulk density, an important factor in the effects of OC on water retention, was measured in situ.Water retention parameters of in situ samples on a gravimetric basis were significantly related to % OC, but those on a volume basis were not. Trends in volumetric WHC for in situ, coarse-textured samples were similar to those for gravimeteric WHC, due to similar bulk densities ranging from 1.30 to 1.40 Mg m–3. However, for in situ peaty soils, trends in volumetric water retention did not mimic those expressed on a gravimetric basis due to low and irregular bulk densities. For laboratory-constructed peat:mineral mixes, FC and WHC were significantly impacted by % OC, however, PWP was not.  The addition of peat material resulted in minor textural changes for sand and loamy sand; hence, the change in texture could not be responsible for the increases in WHC as the result of peat additions. The results for sandy loam were variable. Key words: Bulk density, field capacity, reclamation, water-holding capacity