Saskatchewan Soils Research Articles

Bioavailability, Speciation, and Crop Responses to Copper, Zinc, and Boron Fertilization in South-Central Saskatchewan Soil

An appropriate fertilization strategy is essential for improving micronutrient supply, crop nutrition, yield and quality. Comparative effects of different application strategies of micronutrient fertilizer were evaluated in two contrasting sites/soils (upper slope Chernozem and lower slope Solonetz) within a farm field located in the Brown soil zone of Saskatchewan, Canada. The study objective was to examine the impact of Cu, Zn, and B fertilizer application strategies on their mobility, bioavailability and fate in the soil as well as crop yield responses. The application strategies were broadcast, broadcast and incorporation, seed row banding, and foliar application of Cu, Zn, and B on wheat, pea, and canola, respectively. The study was laid out in a randomized complete block design (RCBD) with four treatment replicates for a specific crop and site. Crop biomass yields were not significantly influenced by micronutrient placement strategies at both sites. Pea tissue Zn concentration (35.2 mg Zn kg−1 grain and 5.15 mg Zn kg−1 straw) was increased by broadcast and incorporation of Zn sulfate on the Solonetz soil. Residual levels of soil extractable available Cu were increased significantly to 3.18 mg Cu kg−1 soil at Chernozem and 2.53 mg Cu kg−1 soil Solonetz site with the seed row banding of Cu sulfate. The PRS™-probe supply of Cu (1.84 µm Cu/cm2) and Zn (1.18 µm Zn/cm2) were significantly higher with broadcast application of corresponding micronutrient fertilizer in the Chernozem soil. Both the chemical and spectroscopic speciation revealed that carbonate associated Cu and Zn were dominant species that are likely to control the bioavailability of these micronutrients under field conditions.

Evaluation of Soil Water Content Using SWAT for Southern Saskatchewan, Canada

Soil water content (SWC) is one of the most important hydrologic variables; it plays a decisive role in the control of various land surface processes. We simulated SWC using a Soil and Water Assessment Tool (SWAT) model in southern Saskatchewan. SWC was calibrated using measured data and Soil Moisture Active Passive (SMAP) Level-4 for the surface (0–5 cm) SWC for hydrological response units (HRU) at daily and monthly (warm season) intervals for the years 2015 to 2020. We used the SUFI-2 technique in SWAT-CUP, and observed daily instrumented streamflow records, for calibration (1995 to 2004) and validation (2005–2010). The results reveal that the SWAT model performs well with a monthly PBIAS < 10% and Nash–Sutcliffe efficiency (NS) and R2 ≥ 0.8 for calibration and validation. The correlation coefficient between ground measurement with SMAP and SWAT products are 0.698 and 0.633, respectively. Moreover, SMAP data of surface SWC coincides well with measurements in terms of both amount and trend compared with the SWAT product. The highest r value occurred in July when the mean r value in SWAT and SMAP were 0.87 to 0.84, and then in June for r value of 0.75. In contrast, the lowest values were in April and May (0.07 and 0.04, respectively) at the beginning of the growing season in southern Saskatchewan. Furthermore, calibration in the SWAT model is based on a batch form whereby parameters are adjusted to corresponding input by modifying simulations with observations. SWAT underestimates the abrupt increase in streamflow during the snowmelt months (April and May). This study achieved the objective of developing a SWAT model that simulates SWC in a prairie watershed, and, therefore, can be used in a subsequent phase of research to estimate future soil moisture conditions under projected climate changes.

Production strategies management to minimize root rot disease in field pea grown on infected southwestern Saskatchewan soils

Multilocational field studies were conducted near North Battleford, Wilkie and Cando in Saskatchewan (SK), Canada during the 2015 (year 1) and 2016 (year 2) summer crop growing seasons to evaluate Aphanomyces euteiches Drechs and Fusarium root rot response to different seed place fertility, preemergence herbicide combination, and foliar fertility. Seven seed place fertility treatments (F1 to F7) were Nitrogen and phosphorus inoculant, liquid Optimize inoculant (LCO), LCO /5.5-25-0-0 (N-P-K-S), LCO /15-25-0-0, LCO /15-25-0-15, LCO/liquid orthophosphate (2-8-1) at 33.7 L/ha/15-0-0-15 and LCO/15-40-40-15 respectively. The four preemergence herbicide (P RE1 to P RE4) were: Glyphosate/Saflufenacil; Glyphosate/Sulfentrazone/Carfentrazone; Glyphosate/Sulfentrazone/Pyroxasulfone and Glyphosate/Sulfentrazone/Trifluralin. Pea was treated with five postemergence (POST 1-5) herbicide with/without adjuvants/foliar fertility at 4-5 node stage as Imazamox/bentazon (Viper) plus 28% v/v Urea Ammonium Nitrate (UAN) – POST 1; Viper plus 2X 28% UAN – POST 2; Viper plus 1X 28% UAN plus foliar fertility – POST 3; Viper plus 2X 28% UAN plus foliar fertility – POST 4 and Quizalofop-p-ethyl at 494.23 mL/ha – POST 5. Growth response, root rot disease severity and yield (kg/ha) were analyzed using SAS statistical software. Significant means were at F < 0.05 were separated by the Fisher’s Protected LSD test at the 5% level. Root rot was significantly lower in P RE4 compared to other treatments. Postemergence herbicide treatments and seed-place fertility recorded significant interaction on root rot incidence and yield. There was over 30% yield improvement between 2016 and 2015 trials due to soil moisture. The trial minimized pea root rot from infested soils and increased yield.

Zinc and copper interactions under variable soil phosphorus and moisture conditions in selected Saskatchewan soils

This study evaluates the influence of phosphorus (P) fertilization (without and with added P fertilizer) and soil moisture (stress and no-stress) on efficacy, fate, and transformation of soil applied micronutrients such as copper (Cu), zinc (Zn), and Cu + Zn in a wheat and pea cropping sequence. Wheat was grown as first crop under controlled environment conditions in which micronutrient fertilizer treatments were applied, whereas pea was grown as following crop with recommended macronutrient fertilizers to understand the residual effects of micronutrient fertilization. The high-P fertilizer application and no-stress moisture condition produced the highest grain and straw yield of wheat. Without P fertilization, there were significant negative effects of a combined application of Cu and Zn on wheat yield in a Dark Gray Chernozem. Yield of the following pea crop did not show response to residual Cu and Zn. Micronutrient fertilization increased the Cu and Zn concentration in wheat and pea grain and straw and resulted in increased after-harvest availability and supply in soils. Apart from the increased concentration in labile fraction, a considerable amount of added Cu and Zn was occluded with organic matter and oxyhydroxide species, respectively. Molecular speciation analyses revealed that carbonate associated was the dominant form of Cu and Zn in the soils. Additional Cu species such as Cu-acetate and methoxide, and Zn species including Zn-sorbed montmorillonite species were identified. Insoluble Cu-phosphate and Zn-phosphate complexes were not identified by speciation analyses and do not appear to be a significant factor controlling Cu and Zn availability in these soils.

Distribution and abundance of Aphanomyces euteiches in agricultural soils: effect of land use type, soil properties, and crop management practices

Aphanomyces euteiches is a soil-borne pathogen that causes root rot in susceptible pulse crops. Although widespread across Canada, A. euteiches was not reported in Saskatchewan until 2012. The distribution of this pathogen across the Canadian prairies is unknown and it is unclear whether it is native to the region. The objective of this study was to conduct a survey of A. euteiches across the major agricultural soils of Saskatchewan, Canada to determine its distribution and to assess the relative importance of factors related to its distribution and possible spread across the province. Soil samples were collected from lentil and pea fields and their associated roadside ditches, as well as from native and tame rangelands. Soil samples were analyzed using a quantitative polymerase chain reaction (qPCR) assay to detect and quantify the presence of A. euteiches. In addition, root rot severity was assessed on affected pea and lentil plants, and the physical and chemical properties of the soils were measured. A. euteiches was present across all land use (i.e., annual cropland, roadside ditches, and rangeland) and soil types in Saskatchewan. A. euteiches abundance was highest in samples collected from annually cropped fields. Within annual cropland, A. euteiches abundance was higher in pea fields than lentil fields. Soil moisture, total and organic carbon, and total nitrogen were positively correlated to A. euteiches abundance in field and roadside soils. Based on this survey, A. euteiches is wide-spread across all the major agricultural regions of Saskatchewan and is not limited to specific soil or land use types. The frequent detection of A. euteiches in native rangeland indicates it is likely native to Saskatchewan. The significant relationship between A. euteiches gene abundance and disease severity in pea fields indicates that the qPCR assay may be a useful indicator for predicting the potential for certain agricultural soils to cause A. euteiches root rot in pea crops.

Sulfur Species Formed in the Seed Row of Sulfur‐Fertilized Soils as Revealed by K‐Edge X‐ray Absorption Near‐Edge Structure Spectroscopy

Core IdeasKnowledge of the S fertilizer reaction products is important for understanding the behavior and efficacy of S fertilizers in soils.Sulfur K‐edge X‐ray absorption near‐edge structure spectroscopy is a useful tool for identifying the soil S species formed following application of different fertilizer forms under field conditions.Knowledge of S fertilizer reaction products following application is needed to predict the ability of different fertilizer forms to provide sufficient plant‐available S to crops. K‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy and wet chemical analysis techniques were used to identify the soil S species formed week to months after fertilization in the field on Brown Chernozem and Black Chernozem soils in Saskatchewan, Canada. The S fertilizer forms were ammonium sulfate, liquid ammonium thiosulfate, gypsum, elemental S, and a zero‐S control treatment. Treatments were applied at seeding at 20 kg S ha−1. Sulfur as ammonium sulfate, ammonium thiosulfate, and gypsum increased the extractable SO4–S in the seed row 1 wk after application; thereafter, it decreased through plant uptake and runoff. For all fertilizers, total S concentration in the seed row increased after application and decreased over time. The XANES results showed that the highly oxidized sulfate form of S was dominant (45–55%) in ammonium sulfate‐ and gypsum‐treated soils 1 wk following application. Thereafter, the proportion as sulfate decreased over time while the reduced and intermediate S forms increased. The proportion of reduced S was highest in the elemental S and ammonium thiosulfate treatments and the proportion in oxidized forms increased from Week 1 to Week 8. Overall, the highly oxidized fertilizer S forms applied (sulfates) transformed to intermediate and reduced S species via immobilization and reduction processes, whereas the highly reduced forms (e.g., elemental S) underwent some oxidation as reduced S decreased and highly oxidized sulfate increased.

An Assessment of Traditional Chemical Indicators of Atmospheric Pollution in Northern Saskatchewan Forest Soils

Core Ideas Concentrations of pollutants in Saskatchewan forest soils are low but are highly variable. Distinct spatial patterns in surface soil pollutant concentration are evident. Patterns in soil Hg and V and SO42− are strongly related to soil organic matter. Concentrations of Cu, Ni and Zn influenced by soil factors in addition to organic matter. Atmospheric deposition plays a minor role in pollutant levels in northern Saskatchewan soils. Long‐range transport and subsequent atmospheric deposition of pollutants has led to soil contamination around the globe. Northern Saskatchewan is downwind of major emissions of sulfur (S), nitrogen (N), and heavy metals vanadium (V) and nickel (Ni) associated with oil sands activities, leading to concerns over possible soil contamination. In this study we sampled 200 forested sites spanning five ecoregions of Saskatchewan. Surface (A‐horizon) soils were measured for a suite of traditional chemical indicators of atmospheric pollution (e.g., SO42–, NO3−, Hg, heavy metals). In general, metal concentrations in surface soils were among the lowest reported in the literature indicating low levels of soil contamination. Despite the remote location of the sites there was a large range in pollution soil indicators in surface soil. For example, Hg concentrations were between 0.6 and 53.3 μg g−1, V concentrations varied from &lt;0.02 to 161 mg kg−1, and extractable SO42– was between 0.2 and 52.2 mg kg−1 and distinct spatial patterns were evident. Higher concentrations of pollutants were observed in southern, eastern and northern parts of the study area. Much of the variability in surface soil chemistry was explained by soil factors and in particular organic matter as the dominant controls of these pollution indicators. Lower values of these indicators were found in sandy soils low in organic matter such as those occurring in the Athabasca Plain located south of Lake Athabasca closest to oil sands activities.

The response of a high-yielding canola hybrid to sulfur fertilization in three contrasting Saskatchewan soils

Canola (Brassica napus) is the primary oilseed crop in western Canada; however, it is often grown on sulfur (S)-deficient soils. Moreover, canola has a high S demand compared to cereals and, therefore, is particularly sensitive to S deficiency. This study examined the growth and nutrient uptake responses of a high-yielding canola hybrid cultivar to S fertilization when grown on three contrasting soils differing in S fertility, with and without the addition of fertilizer S. The soils were collected from three soil-climatic zones within Saskatchewan (Brown, Black, and Gray) and three different fertilizer S forms were used: ammonium sulfate (AS); ammonium thiosulfate (ATS); and a composite fertilizer containing nitrogen (N), phosphorus (P), and S (NPS; 50-50 blend of sulfate (SO4) salt and elemental S). Sulfur fertilization increased the canola biomass, along with plant uptake of N, P, and S on all three soils. Fertilizer S use efficiency (i.e. recovery) ranged from 11-75%. For all three soils, the general trend among fertilizer S forms for biomass, nutrient uptake, and fertilizer use efficiency was AS > ATS > NPS. The greatest differences were observed with the Gray soil, which had the poorest S fertility. Residual soil SO4 after harvest was greater for ATS and NPS; reflecting continued oxidation of thiosulfate and elemental S to SO4. Principal component analysis demonstrated the importance of tissue N:S ratio as a key diagnostic measurement related to canola growth and nutrient uptake in S-deficient soils.

Effect of weed control methods on growth of five temperate agroforestry tree species in Saskatchewan

Most tree species in agroforestry plantings are intolerant to vegetative competition and sites must be intensively cultivated to eliminate weeds. Many studies have been conducted to investigate what factors limit seedling growth because of the presence of vegetative competition in forest environments; however on agricultural sites there are few studies on weed management options for tree planting. This research quantified and compared growth of Manitoba maple (Acer negundo), green ash (Fraxinus pennsylvanica), Colorado spruce (Picea pungens), Scots pine (Pinus sylvestris) and Walker poplar (Populus x Walker) in response to combinations of in-row and between-row weed control methods. The study was established on an agroforestry planting on agricultural soils in Saskatchewan. Treatments included in-row weed control using herbicides or plastic mulch and between-row weed control using tillage compared with a non-weeded control. Weed control positively affected annual height increment, basal diameter and height of the agroforestry species. The impacts of weed control versus no weed control were significant in almost all instances. However, tree species responded differently to the method of weed control. Weed control by herbicide and plastic mulch were not significantly different for four of the five species under investigation. This research will help with prescribing weed control methods for agroforestry and afforestation plantings on agricultural soils.

Relationship between Manure Management Application Practices and Phosphorus and Nitrogen Export in Snowmelt Run-off Water from a Black Chernozem Saskatchewan Soil

In Saskatchewan, soil nutrients released from land-applied solid cattle manure (SCM) and liquid hog manure (LHM) could be subject to off-field export via spring surface run-off water and/or subsurface leaching from melting snow. The objective of this study was to determine how the placement of SCM and LHM using surface and subsurface application methods affects the amounts of soluble reactive phosphorus (SRP), nitrate-nitrogen (NO3-N) and ammonium nitrogen (NH4-N) exported in simulated snowmelt run-off. Intact soil slabs were collected post-harvest in Oct. 2008 and Oct. 2009 from an annually cropped Black Chernozem in east-central Saskatchewan having treatments of: 1) a control, with no SCM or urea fertilizer added and 2) SCM applied at a rate of 60.6 t ha-1 for 2 years as: surface broadcast, broadcast and incorporated and subsurface banded. For comparison purposes, intact soil slab monoliths were collected post-harvest in Oct. 2009 from an annually cropped Black Chernozem in east-central Saskatchewan having treatments of: 1) a control, with no LHM or urea fertilizer added; 2) LHM broadcast and incorporated at a rate of 37,000 L ha-1 for 12 years; and 3) LHM subsurface banded at rates of 37,000 L ha-1 and 148,000 L ha-1 for 12 years. Run-off water and leachate were collected under two different simulated prairie spring melt conditions: 1) thawing soil slabs containing snow that slowly melted on the surface; and 2) frozen soil slabs with run-off water applied to the surface and allowed to run-off across the frozen soil surface. Export of SRP in the thawing soil slabs that had SCM applied in subsurface bands was 0.51 kg P ha-1 and was significantly higher than the non-manured control (0.07 kg P ha-1). Dissolved NO3-N exported in water running across the frozen soil slabs was highest in the broadcast and incorporated treatment (0.30 kg N ha-1). All SCM manured treatments had higher export of nitrate (0.2-0.25 kg NO3-N ha-1) compared to the non-manured control (0.07 kg ha-1). There was no significant (P ≤ 0.10) effect of placement method on SRP, NO3-N and NH4-N export on thawing or frozen SCM soil slabs. Export of SRP was less in LHM treatments than SCM treatments. In thawing soil slabs with 148,000 L ha-1 LHM treatment, the P export was 0.05 kg P ha-1 and was greater than the control treatment (0.01 kg ha-1). Rate of application and manure type appears to be more important than method of placement in influencing P and N transport in melt water on these soils.

Effects of seed-placed sulfur fertilizers on canola, wheat, and pea yield; sulfur uptake; and soil sulfate concentrations over time in three prairie soils

ABSTRACTThe form of sulfur fertilizer can influence its behavior and crop response. A growth chamber study was conducted to evaluate five sulfur fertilizer forms (ammonium sulfate, ammonium thiosulfate, gypsum, potassium sulfate, and elemental sulfur) applied in seed row at 20 kg S ha−1 alone, and in combination with 20 kg phosphorus pentoxide (P2O5) ha−1, to three contrasting Saskatchewan soils. Wheat, canola, and pea were grown in each soil for 8 weeks and aboveground biomass yields determined. The fate of fertilizer was evaluated by measuring crop sulfur and phosphorus concentration and uptake, and supply rates and concentrations of available sulfate and phosphate in the seed row. Canola was most responsive in biomass yield to the sulfur fertilizers. Sulfate and thiosulfate forms were effective in enhancing soil-available sulfate supplies in the seed row, crop sulfur uptake, and yield compared to the elemental sulfur fertilizer. Combination of sulfur fertilizer with monoammonium phosphate may provide some enhancement of phosphate availability, but effects were often minor.

Technoeconomic analysis of small-scale farmer-owned Camelina oil extraction as feedstock for biodiesel production: A case study in the Canadian prairies

This study evaluated costs and profitability associated with small scale camelina oil extraction plant in the Canadian Prairies for the purpose of selling camelina oil for further biodiesel production. In this case, Camelina sativa is targeted for production on underutilized summerfallow land to avoid displacement of crop lands. Saskatchewan soil zone 7A has the capacity to provide camelina for oil extraction based on small scale capacities of 30,000–120,000tannum−1 and capital investment of $10-24 million. Oil production price is reduced with increased camelina oil content, field yield, plant scale, and camelina meal price. Oil production costs range from $0.39 to $1.88L−1 when camelina meal has a market value of $0.30kg−1. These results provide an informative basis for investment decisions by farmers and investors vis-à-vis the advancement of farm-adoption of camelina as a dedicated industrial crop, as well as the development of an integrated camelina-to-processing oilseed value-chain.

Study of polar desert carbon yields many questions

Study of polar desert carbon yields many questions

Crop and Soil Responses to Fertilization with Distillers’ Grains–Derived Manure in a Saskatchewan Soil

A 2-year field trial was conducted to evaluate crop and soil responses to application of manure from cattle fed distillers’ grain (DGM) in comparison with manure from cattle fed regular barley grain (BGM). Manure addition in general promoted grain and straw yield and increased plant nitrogen (N) and phosphorus (P) uptake in both years by approximately 30–50%. In the first year, effect of manure type on crop responses was insignificant, which is consistent with the similar chemical composition of both manures. In the second year, P recovery was greater in DGM treatments, presumably related to a relatively greater P in DGM. Manure application in general increased soil residual nitrate nitrogen (NO3– N) and available P contents at 0–15 cm deep. The high background fertility of studied soil together with the excess moisture during the second year may have masked the significant effects of manure type on most crop and soil responses during this study.

Zinc fertilization of lentil for grain yield and grain zinc concentration in ten Saskatchewan soils

ABSTRACTFertilization of grain legumes with zinc (Zn) can affect both marketable yield and Zn content of the grain, which is important in addressing human nutritional deficiencies in certain regions of the world. A pot experiment was conducted to determine the response of three different market classes of lentil to Zn fertilization using ten surface soils from Saskatchewan (Canada). The distribution of Zn among labile and stable fractions chemically separated from the soil was also determined in the ten prairie soils and related to the lentil responses observed. The three market classes of lentils (large and small green, small red) were grown without Zn (control), and with 2.5 and 5 kg Zn ha−1 added as zinc sulfate to each soil prior to planting. Zinc fertilizer application significantly influenced grain yield and was soil dependent. A significant increase in grain yield over the control was observed from application of Zn on some low organic matter, high pH Brown Chernozem soils whereas a decrease in grain yield over control was observed in other soils such as a Black Chernozem of high organic matter content and low (<7) pH. Lack of positive yield response to addition of Zn were related to measured high diethylene triamine pentaacetic acid (DTPA) extractable and plant root simulator (PRS) resin membrane probe Zn, and large amounts of native Zn in exchangeable and iron/manganese (Fe/Mn) oxide bound fractions. Application of Zn fertilizer generally increased the grain concentration of Zn. For example, an increase of ∼20% in Zn concentration over control was observed when 5 kg Zn ha−1 was added to a loamy textured low organic matter Brown Chernozem soil. Overall, small green lentil was more consistent in producing a positive response to Zn fertilizer application on soils with low plant available Zn compared to large green lentil and small red lentil.

Effect of Application of Liquid Swine Manure on Soil Organic Carbon and Enzyme Activities in Two Contrasting Saskatchewan Soils

&lt;p&gt;Repeated application of animal manure to agricultural fields as a source of plant nutrients has led to questions concerning the impact of this practice on soil organic carbon (C) and biochemical properties, specifically the activity of soil enzymes. There are also some environmental concerns of using livestock manure. The objectives of this study were to determine the effects of repeated applications of liquid swine manure (LSM) on total organic C (TOC), light fraction organic C (LFOC) and on the activity of the soil enzymes (arylsulfatase, alkaline phosphatase and urease) in two contrasting soil-climatic zones and cropping systems in Saskatchewan. Liquid hog manure was applied annually at 37,000 L ha&lt;sup&gt;-1&lt;/sup&gt; and 74,000 L ha&lt;sup&gt;-1&lt;/sup&gt;rates for three years at Melfort (Mollic Cryoboralf) and for four years at Plenty (Typic Boroll) in Saskatchewan, Canada. Soil samples were collected to a depth of 0-15 cm in the spring of 2003 and analyzed for TOC, LFOC and enzyme activities. Annual application (37,000 L ha&lt;sup&gt;-1&lt;/sup&gt;) and larger application made every two years (74,000 L ha&lt;sup&gt;-1&lt;/sup&gt;) of LSM at Melfort increased LFOC, which was attributed to stimulation of plant growth and thus residue inputs, from the nutrients contained within the manure. Applications of LSM at 37,000 L ha&lt;sup&gt;-1&lt;/sup&gt; and 74,000 L ha&lt;sup&gt;-1&lt;/sup&gt; at the Plenty site increased both TOC and LFOC concentration when compared to the control. Soil at the Plenty site is a Typic Boroll of heavy clay texture, which aids in protecting soil organic matter (SOM) from decomposition by soil microorganisms. Melfort was the only site that responded to LSM applications in terms of increased enzyme activity, which may be a result of a shorter application history. The Melfort site also had significantly higher LFOC in the manure treatments compared to the other site and LFOC has been linked to enzyme activity. The results of this study indicate that it may take a long period of time for addition of LSM to produce measurable changes in TOC and LFOC, as the effect from LSM is mainly from the stimulation of plant growth rather than from direct additions of C, and the nutrients contained in the LSM may potentially enhance microbial decomposition. In soils that receive repeated applications of LSM, nutrient loading may contribute to reduced enzyme activity after a period of time.&lt;/p&gt;

First-Rotation Yields of 30 Short-Rotation Willow Cultivars in Central Saskatchewan, Canada

The Government of Saskatchewan is evaluating whether biomass crops can be successfully used as an affordable, reliable, and environmentally sustainable bioenergy source. The objective of this study was to determine the first 3-year-rotation biomass yields of 30 willow cultivars planted in central Saskatchewan. Annual willow morphological data were collected throughout the first rotation, and stem biomass equations were developed. A willow yield map was produced for the SV1 cultivar across climates and soils of Saskatchewan. The majority of willow biomass equations were with high R2 values (>0.90), and there was a strong agreement between equation-derived yield and harvested biomass (RMSE = 13.6 %; bias = -3.3 %). The average diameter, height, and stem count of 3-year-old stems were 14.1 (standard deviation (SD) =1.7) mm, 304.7 (SD = 45.4) cm, and 8.7 (SD = 1.8), respectively. The average first-rotation harvested yield was 10.5 (SD = 3.3) Mg ha−1, and the average survival rate was 81 %. Simulated SV1 productivity was 13.6 and 11.8 Mg ha−1 across marginal agricultural lands of the Prairies (1.7 million ha) and Boreal Plains (0.4 million ha) ecozones, respectively. Low growing degree days, heavy clay soils, low nitrogen availability, and winter stem dieback at these northern latitudes were the main factors to influence willow production at relatively lower yields observed in this study. Based on first-rotation results, the Tully Champion cultivar had the highest potential to be utilized as biomass feedstock in Saskatchewan, producing 17.4 Mg ha−1, which was 70 % greater biomass than the average yield of the other 29 cultivars. The use of willow as a bioenergy source appears promising, but further research is needed.

Effect of boron on clubroot of canola in organic and mineral soils and on residual toxicity to rotational crops

Deora, A., Gossen, B. D., Hwang, S. F., Pageau, D., Howard, R. J., Walley, F. and McDonald, M. R. 2014. Effect of boron on clubroot of canola in organic and mineral soils and on residual toxicity to rotational crops. Can. J. Pant Sci. 94: 109–118. Application of boron (B) has been reported to reduce clubroot severity in various Brassica spp., but residual B can have phytotoxic effects on other crops in the rotation. The objective of this study was to test the efficacy of broadcast application of B for clubroot suppression in canola (B. napus) and the effect of residual B on wheat, barley, field pea and canola. Field trials to assess clubroot suppression by B at various rates (1 to 64 kg B ha−1) were conducted in organic (Ontario) and mineral soils (Alberta, Quebec) heavily infested with Plasmodiophora brassicae in 2011 and 2012. Phytotoxicity was not observed in canola until applications rates exceeded 48 kg B ha−1. Boron did not reduce clubroot incidence at any site, irrespective of rate, and only reduced severity at the organic soil site at 6 wk after seeding. There was a small increase in shoot weight and yield of canola with increasing B application rates at the organic soil site. The potential phytotoxicity of residual B (4 to 16 kg B ha−1) was assessed in mineral soils in Ontario and Saskatchewan in 2012. Toxicity symptoms were noted initially in most of the crops, but seedlings recovered quickly and there was no significant reduction in fresh weight at harvest or seed yield of most of the cultivars. The present study indicates that pre-plant broadcast application of B delays clubroot development and increases vegetative growth and yield compared with non-treated plants in organic soil. Also, even high residual rates (16 kg ha−1) of application are unlikely to have a negative effect on crops in rotation in mineral soil. However, the effect of B application on canola yield found in this study was not sufficient to justify application for commercial canola production, even where clubroot is prevalent.

Freeze–thaw cycles and soil water content effects on infiltration rate of three Saskatchewan soils

Fouli, Y., Cade-Menun, B. J. and Cutforth, H. W. 2013. Freeze–thaw cycles and soil water content effects on infiltration rate of three Saskatchewan soils. Can. J. Soil Sci. 93: 485–496. Many soils at high latitudes or elevations freeze and thaw seasonally. More frequent freeze–thaw cycles (FTCs) may affect ecosystem diversity and productivity because freeze–thaw cycles cause changes in soil physical properties and affect water movement in the landscape. This study examined the effects of FTCs (0, 1, 5, and 10) and antecedent soil water content [at soil water potentials (SWP) −1.5, −0.033 and −0.02 MPa] on the infiltration rate of three Saskatchewan soils (a clay, a loam, and a loamy sand). A tension infiltrometer was used at tensions [water potentials of the tension infiltrometer (WPT)] −5, −10 and −15 cm. Infiltration rates increased with increasing SWPs for the loam and clay soils due to higher infiltrability into drier soils. Infiltration rates decreased with increasing SWPs for the loamy sand, probably the result of less surface tension, unimodal porosity, and increased gravitational potential. Infiltration rates either decreased or did not change with increasing FTCs, and this may be due to increased water viscosity as temperatures approach freezing. Also, ice may have formed in soil pores after frequent FTCs, causing lower infiltration rates. Infiltration rates for clay at −1.5 MPa were higher than for loam or loamy sand, probably the result of clay mineralogy and potential shrinking and cracking. Soil texture and initial water content had a significant effect on infiltration rates, and FTCs either maintained or lowered infiltration rates.

Lentil Performance in Response to Weather, No‐Till Duration, and Nitrogen in Saskatchewan

Increased soil N in no‐till (NT) systems can interfere with biological dinitrogen fixation (BNF), stimulate vegetative biomass, and affect harvest index (HI) and yield of lentil (Lens culinaris L.). In the black soils of Saskatchewan, the effects of short‐term (5–7 yr: ST) and long‐term (28–30 yr: LT) NT practices on lentil were investigated in two experiments from 2006 to 2008. One trial tested the effects of NT duration on plant N and yield of five cultivars; the second examined the response of a late‐maturing cultivar to NT duration at four rates of N fertilization. In both studies, average grain yield in 2006 and 2007 (warm seasons) was 21% greater than in 2008 (cool season), although total rainfall and plant N content was similar in 2007 and 2008. Average soil available N over the years was 23% greater in LT than ST, but the cultivars had 33% less N and 28% less yield in LT than ST in a dry year (2006), and similar performance in LT and ST in the wet years (2007 and 2008). The 60 kg N ha−1 treatment in the second trial diminished the yield difference between LT and ST in 2006. The only BNF measurement in 2008 showed that the cultivars fixed 10% less atmospheric N2 in LT than ST in this year. Overall, cool and wet growing conditions stimulate vegetative biomass and lower HI and yield of lentil, whereas a possible reduction of lentil BNF in NT systems is less likely to affect lentil yield.