Recent discussions on soil health, soil degradation, and soil security have increased awareness of Canada’s forests and their soils as national assets. Foremost is their ability to support timber production, but forest soils also cycle nutrients, store and filter water, sustain biodiversity, among other important ecosystem functions. Organic carbon is recognized as an integral component of forest soil’s ability to support these ecosystem services. While broad-scale quantification of forest soil carbon stocks exists, knowledge gaps remain about the characterization and persistence of this carbon. In addition, despite the significance of forest soils, there is a lack of understanding on baseline forest soil condition, and a lack of common indicators for evaluating soil degradation. We established a network of 17 long-term forest soil research sites covering a diverse range of environmentally and economically important forest regions of the country to address these knowledge gaps. Our objectives here are to introduce the network and illustrate how it can be used to address current research topics. With the network and a standardized sampling design, baseline and soil carbon data were collected from both mature and disturbed forest sites. With these data we aim to better understand soil carbon persistence, thus leading to improved modelling of forest soil carbon dynamics, and to identify measurements sensitive to changes in soil condition for soil degradation reporting. Many of these long-term research sites have previously informed our understanding of forests and forest soils; by highlighting these sites, we aim to identify their continued value to forest research.
Secondary and combined papermill biosolids (PB) are a well-known source of nitrogen (N) for crops, but the available information relating efficient N release to potential factors is fragmented. A meta-analysis was carried out, involving 26 independent studies and 121 observations from multiple experiments (92 for PB and 29 for fertilizer N as a reference). Varying factors related to crop practices, soil properties, and PB characteristics were investigated for their effects on crop yield and plant N accumulation in temperate agricultural regions. The results of meta-analysis revealed that the carbon-to-nitrogen (C/N) ratio of PB and material organic C added accounted for the differences in effect sizes for crop yields, particularly in field studies involving crops with a high N requirement. Conversely, effect sizes for plant N accumulation increased with high application PB rates and amount of total N applied. Moreover, both a low C/N (<15) and a high C/N (>25) ratio were found to increase effect sizes for plant N accumulation. No significant effect was detected for soil properties. Globally, 17% of the total N in PB, equivalent to 39% of fertilizer N, was recovered in the crop. The N recovery percentage was higher in crops with high N requirements and a long growing season, indicating that these crops benefitted more from the N released from PB and would be ideal recipients for PB application. Our results confirm the value of PB as N fertilizer and can help producers and agronomists to finetune their fertilization programs.
The armed conflict in Syria has caused severe and long-lasting degradation of agricultural soils in Raqqa Governorate, historically one of the country’s most productive cereal-growing regions. Conflict-related bombardment, destruction of irrigation infrastructure, climate-induced drought, and widespread contamination from explosive remnants of war threaten soil health, food security, and sustainable agricultural recovery. Existing evidence indicates elevated concentrations of potentially toxic elements in agricultural soils near conflict zones, while large areas of farmland remain inaccessible or environmentally unsafe. This viewpoint highlights critical research gaps related to soil contamination, heavy metal bioavailability, and post-conflict land rehabilitation. We recommend systematic soil monitoring, development of locally adaptable remediation strategies, rapid field-testing approaches, and integration of environmental assessment into agricultural recovery programmes. Addressing post-conflict soil degradation is essential for long-term food security, public health, and ecological recovery in Syria.
Chelator-assisted phytoextraction can alter metal mobility in soils by modifying soluble and extractable fractions. However, the role of oxalic acid (OA), especially in combination with synthetic chelators, in regulating vanadium (V) mobility in alkaline soils remains largely unexplored. This study evaluated the effects of citric acid (CA) and OA, applied alone or in combination with ethylenediaminetetraacetic acid (EDTA), on V mobilization and plant uptake by Brassica juncea grown in alkaline soil spiked with 200 or 400 mg V kg⁻1. A 13-week greenhouse experiment was conducted using five treatments (control, CA, OA, EDTA + CA, and EDTA + OA) with chelators applied in two split applications during plant growth. At 200 mg kg⁻1 soil V, combined EDTA + OA significantly increased pore water V (5.6 mg L⁻1) and NaNO3-extractable V (9.6 mg kg⁻1), resulting in greater leaf V accumulation (6.6 mg kg⁻1) among treatments without visible phytotoxicity. In contrast, natural chelators alone did not significantly alter V mobility. At 400 mg kg⁻1 soil V, pore water V, NaNO3-extractable V (21–23 mg kg⁻1), and plant V were all significantly higher than at 200 mg kg⁻1, and chelator application did not further increase V mobilization. Increased V availability at this higher contamination level reduced plant biomass and showed mild phytotoxic symptoms. The findings demonstrate that V phytoavailability in alkaline soils is governed by contamination-dependent changes in soil solution V and NaNO3-extractable fractions, underscoring the contamination-dependent control of soil solution and labile V fractions in regulating V mobility in alkaline soils.
Soil biological communities are increasingly studied in relation to soilborne pathogen populations and disease incidence in agricultural systems. This study examined how land-use intensity and soil biological structure influence Rhizoctonia solani DNA detected in field soils across Prince Edward Island, Canada. Field soils (n = 59) representing high (2-3 years rotation), medium (4 years rotation), and low (undisturbed) land-use intensities were analyzed for R. solani DNA, soil chemical properties and nematode community composition. Across field soils, R. solani DNA concentrations were negatively associated with total C and N but positively related to particulate organic C and autoclaved citrate extractable protein, indicating relationships with both the quantity and quality of soil organic matter (SOM). A soybean microcosm experiment using a subset of 12 soils differing in land-use history and nematode community structure further assessed R. solani DNA and disease severity under controlled conditions. Soils with lower nematode structural indices and a history of disturbance exhibited higher R. solani DNA concentrations and greater disease severity, whereas undisturbed soils generally had lower values. Inoculation with R. solani AG2-2 LP resulted in reduced nematode structure indices. At the family level, Pratylenchidae and Aphelenchidae were positively correlated with disease severity, while Aporcelaimidae and Tylencholaimidae were negatively associated. Overall, R. solani DNA levels and disease severity were associated with SOM characteristics and food-web structure, highlighting links between soil properties, biological communities, and R. solani dynamics across land-use intensities.
Changes in the natural abundance of the stable carbon-13 isotope (S13C) represent a tracer for soil C dynamics. We investigated the long-term effects of liming (0-12 Mg ha-1) and P fertilization (0 and 15.6 kg P ha-1 year-1) on the vertical S13C distribution and soil C concentration in five layers to 1 m depth. Liming and P fertilization had only small effects on S13C and soil C, whereas soil depth strongly influenced both. These results indicate that, in coarse sandy soils, isotope-based C3-to-C4 conversion studies can be interpreted without accounting for the effects of liming and P fertilization.
Due to the presence of a large amount of calcium hydroxide hydration products and high alkalinity in traditional Portland cement, the vegetation performance of the prepared cement-stabilized soil is poor. This paper uses magnesium phosphate cement (MPC) with neutral pH, high cohesiveness, and nutrient slow-release function as a cementitious material to prepare plant cement-stabilized soil for slope ecological restoration. The physical and chemical properties of MPC-stabilized soil were tested and analyzed. The experimental results indicate that the hydration product struvite of MPC binds soil particles together, forming a larger water stable aggregate structure and significantly improving the compressive strength and water stability of soil. The nutrient slow-release function of struvite significantly enhances soil N and P nutrients. Therefore, MPC-stabilized soil has great potential for application in reducing soil erosion on exposed slopes and promoting rapid vegetation restoration.
Soil hydrophobicity is a limiting factor in agricultural systems with limited water resources. Biochar is a wetting agent that influences the water behavior in hydrophobic soil. This study was conducted to investigate the effect of different amounts of sugarcane biochar (0%, 2%, and 5% w/w) on soil pore size distribution and soil water retention curve in soils with strong and extreme water repellency with the water penetration time of 150 and 1230 s, respectively. A non-hydrophobic soil was also considered as a control. Results showed that at strong and extreme soil hydrophobicity levels the volume of soil macropores decreased by 11.7% and 41%, respectively, compared to non-hydrophobic soil. While this decrease was 11% and 30% for mesopores and only 3.2% and 9.5% for micropores. Increasing the amount of biochar increased the volume of macro, meso, and micropores in the soil with the greatest impact on macropores. In addition, the impact of hydrophobicity on the reduction of soil effective porosity decreased with increasing biochar application rate. Increasing biochar increased the volumetric water content of the soil especially at matric suctions of 0-100 hPa. Increasing hydrophobicity generally decreased the water held in the soil at all three biochar levels. increasing hydrophobicity to strong and extremely hydrophobic levels caused a decrease of 4.5% and 14% in soil available water compared to non-hydrophobic soil, respectively. These results showed that increasing the amount of biochar reduced the negative effect of hydrophobicity on water retention in the soil.
Remote sensing (RS) has been widely applied to map soil salinity in landscapes where salinity exhibits strong spatial contrasts, characterized by high electrical conductivity (EC) values. However, its effectiveness in regions dominated by low EC values remains less understood, particularly in irrigated agroecosystems where salinization processes differ from natural dryland settings. This study evaluated RS-based models within the Riverhurst Irrigation District, Saskatchewan, where both irrigation induced salinity and naturally occurring salinity occur, and where the majority of EC values fall within the 0-2 dS/m range. Vegetation and salinity indices derived from 30 m Landsat 8 imagery, together with geomorphometric variables from a 5 m LiDAR-derived digital elevation model, were used to model soil salinity for three depth intervals (0-30, 30-60, and 60-90 cm) using Random Forest (RF) and support vector machine (SVM). Model evaluation on independent test dataset showed that the SVM outperformed RF, achieving a higher coefficient of determination (R2) of 0.77 and a lower root mean square error (RMSE) of 0.48, compared to RF (R2 = 0.66, RMSE = 0.51).
The Mont & eacute;r & eacute;gie's organic soils, vital for vegetable production in Quebec, are highly vulnerable to wind erosion. Their wind erosion, driven by their low particle density, high organic matter content, and poor structural stability, contributes to their high subsidence of 1-4 cm annually. This rapid erosion threatens the long-term use of these soils, as their depth is about 1.2 m, leading to their possible disappearance within the coming 20-50 years. Windbreaks are effective to reduce wind erosion in mineral soils, their performance in cultivated organic soils poorly documented. This study addresses this gap by focusing on windbreaks effectiveness as a soil conservation strategy. Windbreaks impact in mitigating wind erosion was assessed through field measurements, including soil depth samplings at varying distances from the windbreaks, and Light Detection and Ranging (LiDAR) to detect soil erosion spatial patterns. Analysis suggested, despite variability, windbreak hedges may reduce soil erosion by up to 60% annually (to 0.8-0.9 cm year-1), with the most soil loss reduction closest to the windbreaks. Forest also mitigated erosion but with varying effectiveness. Both types of windbreaks were effective seasonally, with the greatest impact observed annually. Statistical analyses confirmed soil depletion decreases near windbreaks. The study showed similar trends between field and LiDAR, indicating that remote sensing could facilitate regular assessment of soil losses. LiDAR detailed subtle soil depth changes, showing erosion and deposition patterns relative to manual sampling. These findings highlight the value of windbreaks as sustainable means of conserving Quebec's organic soils and ensuring their long-term agricultural use.
This study investigated the impacts of long-term application of mineral and organic fertilizers on soil organic carbon (SOC) fractions and carbon management index (CMI) under a faba bean cropping system. The experiment was established in 1996 at the & Ccedil;ukurova University Research Centre in Adana/T & uuml;rkiye and is still ongoing. Since establishment, five fertilizer treatments have been applied each cropping season, including control (no fertilizer), mineral fertilizer (100N-26P-83Kkg ha-1), animal manure (25 tha-1), compost25 (25 tha-1), and compost10 (10 tha-1) with mycorrhizal fungi. In the present study, faba beans were grown and harvested in 2022 cropping season. At harvest, soil samples were collected to a depth of 0-20 cm and analyzed for SOC and its fractions, such as permanganate oxidizable "labile" (POXC) and particulate organic carbon (POC). The soil CMI and carbon sensitivity index were also estimated. Animal manure and compost25 increased bulk SOC and its fractions relative to other treatments. Manure increased bulk SOC, POC, and POXC concentrations by 74%, 226%, and 85%, respectively, relative to the control, while compost25 increased these fractions by 57%, 54%, and 59%. The CMI was also increased by 87% and 57% over the control under manure and compost25, respectively. Cumulative soil CO2 flux did not differ among treatments. In conclusion, long-term manure and compost25 use increased CMI and the labile and particulate SOC pools. The POC fraction showed the highest sensitivity compared to POXC, particularly under manure, indicating its potential as an early indicator of SOC change.
Crop production in Canada demands consistent use of nitrogen (N) fertilizer, which produces substantial nitrous oxide (N2O) emissions. It may be reduced through scientifically supported N management practices, including applying right sources at right time, right rate, and right place (i.e., 4R practices). One promising 4R practice is use of enhanced efficiency fertilizers (EEFs). However, there is a lack of research synthesis quantifying their effectiveness. To address this gap, we conducted a Canada-wide meta-analysis of field research studies to measure the effectiveness of EEFs and their effects when compared to, or combined with other 4R management practices. Here we present the results of two analyses: (i) comparison of EEFs to conventional N fertilizers (21 studies, 291 observations) using the natural-log-of-the-response-ratio as the effect size, and (ii) the comparison of different 4R practices (31 studies, 561 observations) using emission factor (EF) as the effect size. Mean effect sizes were calculated using a generic inverse variance, random effect multilevel model. Overall, EEFs reduced N2O emissions by 11% compared to conventional fertilizers. EEF types had 23%, 15%, 6%, and -9% N2O reductions (with negative values implying an increase) from nitrification inhibitors, dual inhibitors, slow-release, and urease inhibitors, respectively. The most influential moderators for EEF performance were air temperature at fertilization and soil silt content. The best 4R practices were split application (EF = 0.78%) and EEFs (EF = 0.75%), followed by organic fertilizers (EF = 0.8%). The most influential moderators of EFs were annual relative humidity, percent of soil sand, and crop type.
Soil pH is a key component of soil health, influencing chemical, biological, and related processes such as nutrient cycling. Globally, it has been recognized for decades that fertilization with ammonium fertilizers (including ammonium nitrate, urea, and ammonium phosphate) at high rates and/or over long time periods can decrease soil pH, and is of particular concern in soils with naturally neutral pH (6.5-7.0) due to reduced buffering capacity. To investigate acidification in Canadian agriculture, soils were sampled from the 0-5, 5-10, and 10-20 cm depths from long-term research plots in historically neutral-pH soils in Saskatchewan (SK) and Quebec (QC), and a shorter-term N fertilization trial in SK and Manitoba (MB), under a range of fertilization practices including with and without chemical N fertilization, organic management with no fertilizers (chemical or animal manure), and a range of management practices, including tillage and crop rotations. Soil pH ranged from 5.0 to 7.3 in SK and QC soils and up to 8.4 in MB soils, and was consistently lower in plots with long-term ammonium fertilization. For all fertilized plots, soil pH was lowest at the depth of fertilizer placement (5-10 cm) and highest at 10-20 cm, with the greatest pH differences between these depths in no-till plots. Acidification altered exchangeable cation concentrations, decreasing exchangeable calcium and increasing exchangeable aluminum; this indicates that buffering capacity was reduced in many of the studied soils. These results show that acidification is a concern for neutral-pH Canadian soils, warranting further investigation.
Shifting precipitation patterns in British Columbia (BC), Canada, are increasing the challenge of effective overwinter cover cropping in organic vegetable production and driving the need for alternative soil cover options. As an alternative soil cover, farmers are using plastic silage tarps. There is, however, limited understanding about the impact of overwintered tarps on soil conditions or subsequent cash crops. This study compared the impacts of overwinter plastic tarping with cover cropping or no-tarp conditions on plant available nitrogen (PAN), electrical conductivity (EC), volumetric water content (VWC), and crop yield on organic practicing vegetable farms. Between 2019 and 2021, our study spanned three agricultural regions of BC, with replicated field experiments on two farms and unreplicated plots on 12 additional farms. PAN, EC, and VWC were measured in the spring after tarp removal at all farms. Additional measurements were taken at the experimental farms, including PAN throughout the growing season and crop yield. Spring PAN was 1.8–7.8 times greater, and EC was 2.6 times greater under the tarps. Spring VWC varied and was likely related to tarp removal timing. Data indicate that tarps created lower VWC conditions over the winter until early spring after which time VWC under tarped conditions was higher than soil under cover crops. Crop yield was not significantly impacted by overwinter treatment. Our findings indicate that overwintered tarps are an effective soil cover strategy for small-scale organic farmers to conserve soil PAN and influence early spring soil water content under changing precipitation regimes.
Balancing high yield, nitrogen use efficiency, and environmental sustainability is a central challenge around the world. A 15N tracing and a gradient nitrogen application experiment was taken at 12 runoff plots with four treatments, i.e., 0, 90, 120, and 150 kg ha-1 on subtropical sloping red soils of southern China. Effects of N rate on peanut yield, N losses, and soil N balance were systematically evaluated in different growth stages. Results showed that an appropriate N rate (90 kg ha-1) effectively synchronized N supply with crop demand across growth stages: it met early-stage N requirements for vigorous growth, while preserving rhizobial N fixation capacity, thereby maintaining a stable N source during pod-filling and achieving a pod yield of 3866 kg ha-1. In contrast, excessive N application (150 kg ha-1) disrupted this balance, leading to early-stage N surplus, excessive vegetative growth, suppressed nodulation, and a late-season N shortfall, which reduced the harvest index without increasing yield. Environmentally, deep leaching was the primary pathway of N loss, accounting for 67.5% of the total loss. The 90 kg ha-1 treatment significantly reduced N loss while maintaining soil N balance, whereas the high N treatment increased loss by 93.8%. These findings demonstrate that effective N management in peanut systems on sloping red soils should tailor N supply to crop demand patterns rather than simply increasing input. The 90 kg ha-1 rate is recommended to sustain productivity while minimizing environmental risk, providing a scientific basis for sustainable peanut production in the region.
Perennial cropping in annual crop-based rotations promotes soil organic C (SOC) storage. However, SOC gain rate with the inclusion of perennial crops is not adequately examined. We evaluated Canadian publications on SOC storage impacted by the inclusion of perennial crops in annual crop-based rotations. In temperate regions of Eastern Canada, there was 20.9 ± 4.4 Mg C ha−1 or 32.4 ± 8% more SOC storage in perennial rotations compared to annual, in the top 34 ± 3 cm soil over a mean period of 31.4 ± 2.6 years. However, in subhumid and semiarid regions of Western Canada, perennial rotations gained only 5.5 ± 0.7 Mg C ha−1 or 17.7 ± 2.3% in the top 20.8 ± 1.0 cm soil over a mean period of 27.5 ± 2.4 years. On a per year basis, perennially cropped rotations gained 710 ± 135 kg C ha−1 year−1 in the temperate region, and 100 ± 50 kg C ha−1 year−1 on the Canadian prairies. In temperate regions, continuous and discrete perennial cropping had similar SOC change rate, while in subhumid and semiarid regions, the rates significantly differed (250 vs. −10 kg C ha−1 year−1), likely due to yield variation in perennial crop and soil-disturbance effects on SOC storage. The findings revealed regional variations in the SOC gain rate when perennial crops are integrated into annual crop-based rotations. Our findings can refine national and regional SOC models, improving estimates of SOC change for annual–perennial crop conversion.
Phosphorus (P) loss from soils via snowmelt runoff is a major contributor to eutrophication in water bodies across the Canadian Prairies. Reductions in P losses are often achieved using single-component soil amendments. Blended amendments have been shown to stabilize P more effectively than single amendments; however, their effectiveness in reducing P loss with snowmelt flooding is not well understood. This laboratory incubation study, conducted under simulated snowmelt flooding, compared the effectiveness of blended soil amendments with single amendments in reducing P release from six agricultural soils from southern Manitoba. The treatments were unamended (control), single amendment of alum [KAl(SO4)2 & centerdot;12H2O], or ferric chloride (FeCl3) at 2.5 Mg ha-1, single amendment of gypsum (CaSO4 & centerdot;2H2O) or magnesium sulfate (MgSO4) at 2.5 Mg ha-1 or 5 Mg ha-1, and eight amendment blends of gypsum/magnesium sulfate with alum/ferric chloride at different combinations. Treated soils were packed in vessels, flooded, and incubated at 4 degrees C for 56 days. Floodwater samples were collected bi-weekly and analyzed for dissolved reactive P (DRP) concentrations. Blended amendments typically led to greater DRP reductions in floodwater, achieving maximum decreases of 51%-89%, compared to 38%-64% reductions observed with individual amendments. The gypsum and ferric chloride blend (1:1 ratio at 2.5 Mg ha-1) demonstrated consistent effectiveness across all soil types, whereas ferric chloride was the most effective when applied individually. Single amendment of ferric chloride was only slightly inferior to blended amendments, suggesting it would be a viable option to reduce floodwater DRP in most soils.
Brassicaceae oilseed crop residues contain diverse chemical compounds that have the potential to influence nitrogen (N) mineralization and hence recovery from crop residues. This study investigated how glucosinolate (GLS), carbon (C), N, lignin contents, and associated ratios (C:N and lignin:N) in selected Brassicaceae (Argentine canola (Brassica napus L.), industrial mustard (B. carinata L.), Oriental mustard (B. juncea L.), camelina (Camelina sativa L. Crantz), and yellow mustard (Sinapis alba L.)) and non-Brassicaceae (spring wheat, Triticum aestivum L.) crop residues affect N recovery potential and soil N availability. A 120-day laboratory incubation was performed using N-15-labeled residues of these crops. Yellow mustard contained the highest GLS concentration (6.49 & micro;mol g(-1) of tissue) and Argentine canola contained the least (0.02 & micro;mol g(-1) of tissue). Argentine canola (17.8:1) and Oriental mustard (19.5:1) residues had the lowest lignin:N due to their high N concentrations. After 120 days, 47.1%-53.7% of residue N was mineralized and recovered as ammonium-N and nitrate-N. Nitrogen mineralization from the Brassicaceae residues was initially lower than wheat, likely due to inhibitory effects of GLS degradation products on soil microbes. Strong negative correlations were found between N recovery and both GLS concentration (r = -0.737 to -0.846, days 3-28, P = 0.04) and lignin:N ratio (r = -0.631 to -0.552, days 3-56, P = 0.02), indicating that these biochemical properties likely delayed N availability from crop residues at the early-stage. These findings suggest that the biochemical composition of Brassicaceae residues, particularly their GLS content, can delay short-term N cycling and affect nutrient availability for subsequent crops.
Recent publications proposing new definitions of “soil” and “soil science” have stimulated active debate within the Soil Science Society of Indonesia. While these definitions offer valuable planetary, and mechanistic perspectives, our discussions revealed challenges in communicating them to students, practitioners, and policymakers, particularly in regions where soils are primarily understood as biologically active systems central to food security, land stewardship, and livelihood. Motivated by these reflections, we propose a concise and accessible definition of soil science as “the study of soil as a dynamic living ecosystem and resource, examining its formation, properties, and functions within Earth systems to support life and human well-being.”
Responsible agricultural land drainage considers the balance between allowing farmers to manage water while limiting environmental impacts. This study evaluates the role of fertilizer and crop management practices to achieve this goal under Canadian Prairie Pothole Region conditions. In September of 2020, a wetland consolidation project was initiated on a Dark Brown Chernozem (Typic Boroll) using surface ditches to drain eight ephemeral wetland watersheds within a single field. Different fertilizer or crop management practices were applied annually for 3 years to each drained watershed and assessed for their influence on crop phosphorus (P) uptake and yield, along with dissolved reactive P (DRP) concentration and total soluble P load in snowmelt runoff. Practices evaluated included (1) variable rate fertilizer application for annual grain crops; (2) post-harvest grain crop residue incorporation through shallow tillage; and (3) annual forage species mixture for hay harvest, and were compared to an annual grain crop control treatment with constant rate fertilizer application and no post-harvest tillage. Variable rate fertilizer application significantly reduced DRP concentration (64%–69% of control) in 2 of 3 years and total soluble P load (50% of control) in 1 year of snowmelt runoff with no significant crop yield reduction. The forage mixture also significantly reduced DRP concentration relative to the control in 2 years. Differences among treatments are attributed mainly to differences in P fertilizer application rates. Therefore, fertilizer or crop management practices that increase utilization of applied and residual soil P can be effective in reducing P transport from drained agricultural watersheds.
