The filter paper technique consists of obtaining the equilibrium water content of a filter paper that is either in direct contact with a soil sample or inside an airtight container together with the sample but not in direct contact with it. After the final water content of the filter paper is determined, the suction in the soil is estimated from a previously established calibration curve relating the filter paper water content and suction. The ASTM D5298-10 calibration curve is routinely used for indirect suction estimation from Whatman Grade 42 filter paper water content measurements. This note identifies limitations in the calibration curve in ASTM D5298-10 that lead to inaccuracies in the estimation of suction values, particularly for very low filter paper water contents. The paper proposes new equations not subject to these limitations for the calibration curve for Whatman Grade 42 filter paper using the same data used to construct the calibration curve in ASTM D5298-10.

Since animal diet affects manure properties, it is expected that manures from different diets may elicit differences in crop response. The objective of the study was to assess how application of manure from cattle fed with dried distillers grains with solubles (DDGS) and flaxseed (Linum usitatissimum L.) affected N and P availability, dry matter, and nutrient uptake in barley (Hordeum vulgare L.) and camelina [Camelina sativa (L.) Crantz] under controlled environment conditions. Treatments included manure from diets with barley grain (BARL), or barley grain replaced with triticale (× Triticosecale Wittmack) DDGS, flaxseed (FLAX), or both DDGS and flaxseed (DDGS/FLAX). Crops were grown for four consecutive phases (barley–camelina–barley–camelina). The DDGS/FLAX treatment had significantly higher barley dry matter weight (DMW) in phase 1 and camelina DMW in phase 2 than the other three manures (17 vs. 5–13 g kg^-1 soil in phase 1 and 10 vs. 1–7 g kg^-1 soil in phase 2). Barley N uptake in phase 1 and camelina N uptake in phase 2 were significantly higher for DDGS/FLAX than the other manures (222 vs. 82–191 mg kg^-1 soil, phase 1; 146 vs. 20–102 mg kg^-1 soil, phase 2). Our results indicate that cattle diet modifications have the capacity to tailor manure properties for optimum crop production.

Few studies have examined the effect of long-term application of feedlot manure on ground elevation, Ah horizon depth, and color of surface soil. The objective of this study was to examine the effect of manure type (stockpiled vs. composted feedlot manure), bedding (straw vs. wood chips), and application rate (13, 39, and 77 Mg ha^-1 dry wt.) on these soil properties after 17 annual applications. There was also one inorganic (IN) fertilizer treatment and an unamended control. Elevations were measured using a total station, and the Munsell value and chroma measured on field soil and on fine-ground (<150 μm) soil using color charts. Manure type and bedding had no significant (P > 0.05) effect on relative elevation and Ah depth, but relative elevation and Ah depth increased with greater application rates (10.7 cm increase in relative elevation at 77 Mg ha^-1). The Munsell color value was significantly lower or darker for amended than unamended soils and shifted the Chernozemic soil Great Group classification for some treatments from Dark Brown to Black. Overall, greater rates of feedlot manure increased the relative elevation and Ah depth of amended soils and made the surface soil darker, but manure type and bedding had no effect.

Global declines in postsecondary enrollment in soil science programs over the last several decades have been mainly attributed to an overemphasis on the connection with agronomy and production agriculture but recent enrollment increases in the USA suggest change is afoot. To determine if similar trends are occurring in Canada, we inventoried undergraduate soil science course offerings at postsecondary institutions and conducted a survey to assess the status and projected trends in soil science education. We found that 64% of universities and 37% of colleges offer undergraduate soil science courses as part of degrees or diplomas in which knowledge of soil science is important (e.g., agriculture and resource management). In Canada, there are 149 undergraduate soil science courses taught in universities and 58 at colleges. On average, there are 3.2 courses taught at each university and 1.9 at each college that offer soil science courses. Soil science programs at the University of British Columbia, University of Saskatchewan, and University of Manitoba offer between eight and nine soil science courses and represent 17.4% of the national total. Enrollments in all courses across the country are projected to be steady with some anticipated growth, trends that are consistent with those reported in the USA and the Netherlands.

In continuous cereal-based crop rotation, inappropriate residue management such as burning and removing may deteriorate soil properties and crop productivity. The objective of this study was to evaluate the effects of different tillage systems (TSs), nitrogen fertilization, and maize (Zea mays L.) stubble management (SM) on subsequent wheat (Triticum aestivum L.) crop and soil properties. The experiment consisted of three TSs, i.e., shallowing with rotavator (0–10 cm), conventional (0–20 cm), and deep tillage (0–30 cm) as main plots, whereas the subplots were SM (removal, burning, or incorporation) with or without 120 kg N ha^-1 as urea. The treatments were laid out in a split-plot fashion with whole-plot factor in a randomized complete block design. Shallow tillage (ST) increased wheat yield and soil moisture retention, soil mineral N, total N, and organic carbon. Similarly, stubble incorporation with N fertilization enhanced grain yield and soil properties as compared with the stubble removed or burning treatments. Synergetic effects were noted between ST and residue incorporation with N fertilization for grain yield and soil N response. We conclude that in a cereal-based cropping system, ST and maize stubble incorporation accompanied by N fertilization can improve soil properties and productivity of subsequent wheat crop in existing soil conditions.

Concern about the transport of chemicals in groundwater systems has stimulated the development of many models to describe transport in porous media, the most common of which under steady-state conditions is the convection–dispersion equation (CDE). We propose a novel solution to the CDE for predicting profiles of solute concentrations and estimating transport parameters. The solution was adapted from polynomial and exponential boundary-layer (BL) solutions based on BL theory. The accuracy of the new BL solution was dependent on the number of polynomial terms and the properties of the soil. The errors in predicting profiles of solute concentrations and estimating transport parameters were usually lower for a model combining one exponential and two polynomial terms than for a model with only one polynomial term. The new BL solution provides an alternative for simulating solute transport under field conditions and improves the methodology of using BL theory to solve the CDE.

Comparing functional similarity in reconstructed ecosystems with natural benchmarks can provide ecologically meaningful information to measure reclamation success. We examined nutrient supply rate using ion-exchange resins as a measure of ecosystem function in two oil sands reclaimed soils, viz. peat mineral mix (PMM) and forest floor mineral mix (FFMM), and measured fertilization effect on nutrient supply rates in these soils for three consecutive years contrasted with young-fire-disturbed and mature forest stands. Results indicated that nutrient profiles of reclaimed soils were significantly different than natural benchmarks. Phosphorus and potassium supply rates in reclaimed soils were up to 91% lower, whereas S, Ca, and Mg were, respectively, up to 95%, 62%, and 74% higher than in benchmark soils. The expected nutrient flush postfertilization was only apparent in N and P, but the transient effect levelled off the year after fertilization in most cases. Fertilization aligned the temporal trajectory of the nutrient profile in PMM similar to benchmark conditions indicating greater ecological benefit of fertilization than in FFMM. The findings from this study suggest that fertilization focusing on P and K is likely more ecologically appropriate for establishing natural ecosystem function on reclaimed soils in this region of the boreal forest.

For proper fertility management, the influence of soil properties on phosphorus (P) dynamics with fertilizer application should be better understood. We examined the influence of soil chemical properties on P dynamics with the application of monoammonium phosphate (MAP) to alkaline-calcareous soils from Manitoba. Nonfertilized and MAP-fertilized soils (at 30 and 60 kg P ha^-1) were incubated for 8 wk. At 2 wk intervals, we analyzed pore water samples for dissolved reactive P (DRP) concentration, and soil samples for Olsen P (OP) and Mehlich-3 P (M3P) concentrations. Change in pore water DRP concentration with fertilizer application varied from a slight decrease (-0.02 mg L^-1) to a significant, large increase (3.1 mg L^-1) and showed a significant, negative relationship with P sorption capacity. The increase in OP and M3P with fertilizer application was influenced by the rate of P applied, initial soil test P and P sorption capacity. The estimated mean OP and M3P to maintain pore water DRP concentration at 0.2 mg L^-1 were 25 and 48 mg kg^-1, respectively. Fertilizer application at the same rate resulted in a widely varying degree of P saturation (DPS) increment depending on soil properties, indicating the importance of monitoring DPS changes for sustainable fertilizer use.

Collembola are known to feed on a wide range of soil material, predominantly rhizosphere fungi, and root-derived substances. However, diet switching from these usual food sources to living roots (herbivory) was previously demonstrated for one species of collembola, Protaphorura fimata, a euedaphic species. The objective of this study was to determine if diet switching can be applied to another collembola species, Folsomia candida Willem. This hemiedaphic species was given different combinations of maize plants (-13.28% δ¹³C, 3% δ¹⁵N) and ¹⁵N-enriched rye grass litter (-28.88% δ¹³C, 17 516.86% δ¹⁵N) in a C₃ soil system (-27.27% δ¹³C, 5.27% δ¹⁵N) under controlled conditions. After 8 wk, there was clear evidence of root feeding because the δ¹³C signature in collembola tissue was -19.28% in the presence of maize plants alone and -18.29% with maize plants grown in soil mixed with ryegrass litter, whereas collembola in unplanted soil microcosms had a δ¹³C signature of -23.66%. Data analysis with a two-source isotope mixing model indicates that up to 60% of the carbon requirements of F. candida were derived from living maize roots. Whether collembola root feeding is due to grazing on roots directly or on mycorrhiza (root-fungus association) requires further investigation.

Point Pelee National Park (PPNP), located in Leamington, ON, is heavily contaminated with the pesticide dichlorodiphenyltrichloroethane (DDT) that was liberally used for mosquito and pest control in the park from the 1940s until the 1960s. This study was designed to update and enhance information that will advise PPNP personnel on remediation strategies. Building on previous research, a comprehensive soil and sediment sampling, and analytical program was carried out over several years and was completed in 2014. In total, 140 soil, nine sediment, and four water samples were analyzed by gas chromatography/electron capture detection. Dichlorodiphenyltrichloroethane contamination boundaries were defined, and they were determined that this contaminant occurs predominantly in three “hot spot” areas with total DDT levels exceeding 130 000 ng g^-1, which is 19 000% higher than federal guidelines. This information was mapped into an interactive Google Earth platform. Dichlorodiphenyltrichloroethane isomer analysis compared groupings of samples and determined that soil hot spot areas have half-lives ranging from 27 to 40 yr. It was determined that the highest concentrations of DDT (not including DDT’s derivatives) could remain above federal guidelines for a further 220–342 yr. Overall this study improved delineation of DDT hot spots and narrowed the half-life ranges of DDT and its metabolites in PPNP.

Repeated annual application of paper mill biosolids (PB) and liming materials may impact soil functioning, such as nutrient cycling, organic matter decomposition, and microbial activities. The objective of this study was to evaluate the residual effect of 9 yr annual applications of PB and different liming materials on soil microbial community structure and microbial biomass C, N, and P. Treatments consisted of PB at four rates (0, 30, 60, and 90 wet Mg ha^-1), three liming by-products (calcitic lime, lime mud, and wood ash, each at 3 wet Mg ha^-1 with 30 Mg PB ha^-1), and a mineral N fertilizer surface-applied after annual crop seeding. Three years after treatment application ended, soils were sampled from 0–15 to 15–30 cm layers in each plot after corn harvest. Soil microbial community and microbial biomass C, N, and P were higher in the surface layer than deeper. Application of PB significantly increased soil microbial biomass C, N, and P and fungal biomass in both layers and induced changes in microbial community structure. In contrast, application of liming by-products did not affect microbial biomass and community. This study revealed that repeated PB application improved soil biological attributes, and those improvements can be sustained for years.

The dispersion coefficient (D) and retardation factor (R) are key parameters in convection–dispersion equation (CDE). The boundary-layer theory provides a simple and convenient method to solve the CDE for a third-type boundary condition under steady water flow. However, the present boundary-layer solutions cannot accurately describe the solute concentration at higher average pore-water velocities for a long-period solute transport process. In this study, an improved exponential solution to the CDE was developed using boundary-layer theory with the assumption that the resident solute concentration in soil was an exponential function related to the position under steady water flow. The accuracies of three boundary-layer solutions (parabolic polynomial, cubic polynomial, and exponential) were evaluated by comparing with the exact solution in concentration predictions for a third-type boundary condition under steady water flow. The solute concentration distributions calculated from the three boundary-layer solutions were close to those from the exact solution. At higher average pore-water velocities, the exponential solution was better than the polynomial solutions in D and R estimations. Moreover, the feasibility of the three boundary-layer solutions was verified using a column experiment. This study provides an effective way for estimating D and R in laboratory or field studies.

Small-scale dairy farming is economically challenging; however, management intensive grazing practices have allowed many farms to become profitable. Traditional barn housing during cold seasons is a large expense and could be adapted to further economic gains. In this study, three cold season pasture management practices, such as bedded pack (BP) compost amendment, out-wintering (OW) on pasture, and stockpiling (SP) mixed grass–legume pasture forage, were evaluated for impact to soil and forage quality within pasture. Composite soil and forage samples were collected during spring and autumn 2009–2010 for soil physical, chemical, and biological analyses (nematode community structure) and forage quality. Out-wintering favored fungal decomposition (P = 0.089), and all treatments promoted soil food web structure, with a mean structure index value of 63 ± 1.71 SE. Negative impacts to soil health, including physical structure and soil chemistry, were not detected. Impacts to forage quality included decreased degradable protein under SP (P = 0.055) and decreasing relative feed value following SP and BP treatment application (P = 0.025). The small sample size (total n = 16 or eight pairs) and high variability require cautious interpretation, yet minimal negative effects of implementing BP, OW, and SP practices were detected.

Until now, how wetting processes (WPs) and drying processes (DPs) affect the water drop penetration time (WDPT)–soil water content θ (or – water suction ψ) relationship, termed the soil water repellency characteristic curve (SWRCC), has remained unclear. WDPT vs. θ and water retention curves were measured and deduced for four wettable and hydrophobized soils during WPs and DPs. The performances of Gaussian model (GM), Lorentzian model (LRM), and Lognormal model (LGM) were compared for 32 measured SWRCC curves. The R_WDPT, which is the ratio of the maximum WDPT during WPs to the WDPT of similar θ values during DPs, varied between 1.29 and 2.35 for wettable soils and between 1.3 and 138.1 for water-repellent soils, showing that hysteresis effects are important for SWRCC curves during DPs and WPs. Each model’s parameter was physically determined using the measured data. The Gaussian model was ultimately selected to represent the universal SWRCC relationship because of its features and general good performances not only for the unimodal SWRCC curves in both DPs and WPs in this study but also as reported in previously published data. The SWRCC can be roughly determined using two observed WDPT–θ (or water suction) data-points.

Assessing the success of soil reclamation programs can be costly and time-consuming due to the cost of traditional soil analytical techniques. One cost-effective tool that has been successfully used to efficiently analyze a range of soil parameters is reflectance spectroscopy. We used reflectance data to analyze natural and reclaimed soils in the field, examining three key soil parameters: soil organic carbon (SOC), total nitrogen (TN), and soil pH. Continuous wavelet transforms combined with machine learning models were used to predict these parameters. Based on the root mean square error (RMSE), R² value, and the ratio of performance to deviation (RPD), the Cubist model produced the most accurate models for SOC, TN, and pH. The RMSE, R², and RPD values for SOC were 0.60%, 0.80, and 2.2, respectively. The TN model results were 0.05%, 0.81 and 2.5, and pH model results were 0.44, 0.69 and 1.8. Overall, the optimal model can be used to predict SOC and TN accurately, and improvements in the pH model are needed as pH values less than 6.5 were consistently overpredicted.

Increased irrigated production of potato (Solanum tuberosum L.), dry bean (Phaseolus vulgaris L.), and sugar beet (Beta vulgaris L.) in southern Alberta in the 1990s prompted a 12 yr (2000–2011) study to evaluate conservation (CONS) management practices for these crops in 3–6 yr rotations. Conservation management included reduced tillage, cover crops, compost, and narrow-row dry bean. After 12 yr, soil organic carbon (SOC) at 0–30 cm depth increased by 0.48 Mg ha^-1 yr^-1 on a 5 yr CONS rotation, in line with average cumulative compost addition of 154 Mg ha^-1. In contrast, SOC stocks on a 3 yr conventional (CONV) rotation, which did not receive compost, declined by 0.25 Mg ha^-1 yr^-1. Nitrate-N did not accumulate in the soil profile under CONS management, as it was largely influenced by previous crop. In contrast, available P increased with compost addition under CONS management, leading to surface buildup and downward movement in the soil profile. At 0–120 cm depth, the CONS rotations showed 26%–53% higher available P than CONV rotations between 2005 and 2011. Apart from a caveat regarding potential P accrual, the CONS management package in this study was validated as soil building for irrigated cropping systems in southern Alberta.

Mining and natural resource development in the Canadian north has produced large areas of disturbance and volumes of waste, necessitating reclamation. This study focused on building anthroposols in a greenhouse using waste material from Diavik Diamond Mine. There were six substrates (crushed rock, lakebed sediment, processed kimberlite, and its combinations), seven organic amendments (sewage, soil, peat, Black Earth, biochar, and its combinations), a control, and two nutrient treatments (with and without fertilizer). Substrates and amendments were mixed and seeded with three grass species. Soil properties and vegetation responses were assessed. Substrate structure was a challenge; crushed rock and processed kimberlite had little fine material and lakebed sediment was compacted. Processed kimberlite and sewage had metal concentrations (barium, chromium, cobalt, copper, molybdenum, nickel, selenium, and zinc) above guidelines. Vegetation established on all anthroposols, with plant growth and density greatest in crushed rock, followed by 25% processed kimberlite with 75% lakebed sediment and 100% lakebed sediment. Substrates amended with peat and (or) soil had the greatest plant density and belowground biomass; substrates amended with sewage and sewage–soil had greatest aboveground biomass. Fertilizer had a limited effect. With appropriate amendments, waste materials at the mine showed potential as reclamation soils.

Return to equivalent capability is the principle governing land reclamation in Alberta. However, land capability rating systems are seldom used to determine post-reclamation equivalency in agricultural lands. This study used the Land Suitability Rating System for Agricultural Crops (LSRS) to estimate reclaimed soil profile ratings. Baseline soil data for 30 soil series obtained from the Alberta Soil Layer file were changed to yield synthetic data. Admixture was simulated by mixing 10 equal increments of B horizon (subsoil) into the A horizon (topsoil) to a maximum of 50% of initial A horizon thickness. Subsoil density was changed in 2.5% increments above baseline to a maximum increase of 25%. Admixture effects on texture, organic carbon, and thickness of topsoil and density change in subsoil were quantified across these 10 treatment levels and deductions were calculated with the LSRS. At level 10 in which topsoil consisted of 33% subsoil admixture by volume and subsoil density had increased by 25%, capability declined from one to five classes below baseline. Future work will employ quantitative field data to explore the accuracy of these findings and to test the hypothesis that current assessment methods may be unreliable for confirming a return to equivalent capability.

The effect of long-term (20 yr) fertilizer application on soil nitrogen (N) transformation in paddy soils was studied at three sites (Xinhua, Ningxiang, and Taojiang) in Hunan province, China. Four fertilization practices were chosen: chemical fertilizers (NPK), chemical fertilizers plus a medium or high amount of pig manure (MM NPK), chemical fertilizers plus a high amount of pig manure (HM NPK), and chemical fertilizers plus straw incorporated (Str. NPK). A treatment with no fertilization was included as a control (CK). Ten week aerobic incubations were conducted to determine N potential mineralization and nitrification. Application of organic plus chemical fertilizer increased soil organic carbon, total nitrogen, and microbial biomass carbon (C_mic) and nitrogen (N_mic), whereas the response of C_mic/N_mic ratio to fertilizer application varied among sites. Across all sites, the HM NPK treatments had the highest potentially mineralizable N and maximal nitrification rate, and the CK had the lowest. The MM NPK, Str. NPK, and NPK treatments had lesser effects on mineralizable N and nitrification. Results indicated that chemical fertilizer along with a high rate of manure application is an effective method to improve available soil N by increasing the N mineralization rate. However, higher N nitrification was also induced by manure application, which may lead to increased N losses, and also should be considered in practical applications.

Canada’s grain and oilseed production in the Canadian Prairies may be affected by climate change, but the impact of input and diversity has not been assessed relative to projected variability in precipitation and temperature. This study assessed wheat, canola, and barley yields simulated with the environmental policy integrated climate model for historical weather and future climate scenarios in the context of agricultural inputs and cropping diversity at Scott, SK, Canada. Variation of future yield was explored with recursive partitioning in multivariate analyses of inputs, cropping diversity, future growing season precipitation (GSP), and growing degree days (GDD). Agricultural inputs significantly affected wheat yield but not barley or canola. Wheat yield was highest under the reduced input level and lowest under the organic input level. The combination of input and diversity accounted for about one-third of variation in future wheat yield and approximately 10% for barley yield. Most of the variability in yield was correlated with GSP in May–July and GDD in April–June and August–September. Future growing season maximum and minimum temperatures increased by 1.06 and 2.03 °C, respectively, and 11% in future GSP. This study showed how input management and reduced tillage maintained or improved yield, in the context of increased temperature due to climate change.

Poly-γ-glutamic acid (γ-PGA) has shown a significant promotional effect on plant production. However, little is known of the environmental footprint generated from the application of γ-PGA. A laboratory trial was conducted to study the effects of γ-PGA on soil nitrogen and carbon leaching loss and carbon dioxide (CO₂) emission by applying 0, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4, and 0.8 g γ-PGA kg^-1 soil to soil receiving 150 kg N ha^-1 in the form of urea. Results showed that the cumulative loss of ammonium and nitrate decreased by 17.81%–29.31% and 8.27%–52.42% when the application rate of γ-PGA reached 0.1 g kg^-1 soil. Cumulative total dissolved nitrogen loss was diminished by 7.16%–40.10% when the γ-PGA application rate was 0.2–0.8 g kg^-1 soil. Cumulative loss of dissolved organic carbon was rarely affected by the γ-PGA, whereas cumulative CO₂ flux was notably enhanced by 26.87%–180.70%. Soil total nitrogen (TN) and soil organic carbon (SOC) contents varied with the different application rates of γ-PGA; soil TN increased by 6.34%–8.04%, and SOC remained unchanged only when the γ-PGA application rate was 0.4–0.8 g kg^-1 soil. In conclusion, before considering using γ-PGA in an agroecosystem, its effects on both the environment and plant production should be examined.

Thirteen years after cultivating native grassland and establishing continuous wheat (Triticum aestivum L.) and wheat–fallow rotations in southern Alberta, surface soil total N levels were 15% lower, and nitrate (60–90 cm) concentrations were 2.5- and 17-fold greater, than native grassland. Wheat–fallow, even without fertilization, markedly enhanced potential nitrate loss through the root zone.

The boron concentration in soil extracts and ashed plant tissue was quantified with a rapid and reproducible microplate assay. The microsized azomethine-H method required adjustment to reduce pH and chemical interferences in soil and plant tissue samples. Microplate spectrophotometry permits replication and quality control and is suitable for high-throughput analysis.