No-till (NT) often causes prominent stratification of C and nutrients in the soil profile relative to tilled systems. We hypothesize differences in root distribution within the soil profile between NT and tilled systems could be one factor contributing to stratification. We evaluated how NT affects root length density (RLD), root biomass yield (RBY), and root diameter compared with other tillage systems and factors that may affect root characteristics. We reviewed studies until 23 January 2024 where RLD, RBY, or root diameter were reported under NT and tillage. The data on RLD, RBY, and root diameter were tabulated and the weighted log response ratio (M_LRR) and confidence intervals computed. Our meta-analysis showed NT increased RLD in the 0–10 cm depth, but it reduced RLD at 10–20 cm. It increased RBY and root diameter in the 0–20 cm depth and reduced both characteristics at 20–30 cm. Regardless of root characteristics, NT had mixed effects below 30 cm. However, across the soil profile (minimum 50 cm depth), NT had no effect on RLD and RBY. NT-induced changes in roots can be related to increased compaction at the tillage interface. NT stratified both RLD and RBY compared with high-intensity tillage systems, although there were some conditions where NT stratified only RLD or RBY. NT did not induce stratification of RLD and RBY in dry regions, mild, or hot climates, in medium-textured soils, or compared with intermediate-intensity tillage systems. Overall, NT can result in stratification of both RBY and RLD compared with high-intensity tillage systems.

Intercropping or agroforestry systems are among the strategies used to prevent soil erosion or crusting and water loss by evaporation in the bare soil during early growth stage of tree crop plantations. However, the pattern of water use in intercropped, juveline orchard crop plantations is still poorly known. This study aimed to evaluate competition or facilitation for soil water stored by cover crops in rotation and the impact of additional fertilization in a juvenile tung-based intercropping system in southern Brazil during the winter and summer periods of 2012/2013 and 2013/2014 growing seasons. A split plot in randomized complete block design arrangement, with four replications, was used comprising crambe winter cover crop plus poultry manure or nitrogen, potassium and phosphorus (NPK) fertilizer; a mixture of oats and vetch, sunflower, and soybean in rotation; and sole tung as control. Cover crop intercropping significantly increased water content of the surface layer of the juvenile tung soil only at the beginning of the second growing season. The cover crops showed interspecific facilitation for water use by tung during the summer period, but no clear-cut trend for the winter cover crops. The additional organic manure did not enhance profile soil water storage. Any of the summer cover crops (soybean, sunflower, or peanut) could be used for soil and water conservation in juvenile tree crop plantations. Further studies are required during the winter season to establish whether the winter cover crops are competitors or facilitators for stored soil water in agroforestry systems.

Monitoring data are needed to assess the effectiveness of soil conservation measures applied on agricultural lands during pipeline construction. Soil data were collected on the footprint of a pipeline constructed in 2016–2017 in west-central Alberta. Construction practices were expected to mitigate for topsoil loss and admixture, compaction, and erosion. Sites were established on the footprint and on adjacent reference areas on 24 parcels. Field measurements included point-sample results for horizon thickness, bulk density and soil erosion-rate including suspended sediment in runoff, and laboratory measurements from composite samples including pH, total organic carbon and texture. Admixture rate was estimated from change in percentage clay. Topsoil thickness was more variable on the reclaimed footprint than references. Topsoil pH was about 0.4 units higher and percent clay was 6.2% higher on the footprint than references but total organic carbon was not different. Admixture rates in the topsoil at six parcels ranged from 0.18 to 0.60. Penetration resistance on four measured aggregate size classes of subsoil was significantly higher on the footprint than reference. Subsoil loss from rill erosion ranged from 0.1 to 8.1 cm in the first year after construction when little vegetation was present and sediment concentrations in runoff sometimes exceeded 10 g L⁻¹. Mitigations applied to limit soil degradation were less effective than expected. The use of quantitative techniques to monitor soil reclamation outcomes will improve the credibility of results but add costs to the process. Similar monitoring is needed to determine the effectiveness of current reclamation practices.

In Canada, there is a need to implement value-added uses for wood ash (hereafter ash) generated from bioenergy facilities as most ash is landfilled. Ash application to forests can provide benefit via nutrient supply, amelioration of soil acidity and, sometimes, increased tree growth. However, information is limited on the response of conifer species to different wood ash types applied to fine-textured soil typical of north-central B.C. We conducted a 16-month seedling pot trial that examined the response of Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta var. latifolia), and hybrid white spruce (Picea glauca × engelmannii) to high- (HCA) and low-carbon ashes (LCA) applied (up to 10 Mg mineral matter ha⁻¹ equiv.), with and without fertilizer N (200 kg N ha⁻¹ equiv.), to fine-textured forest soil. Pine and spruce exhibited a 1.6- and 1.4-fold increase in shoot biomass at the high rate of HCA with fertilizer N. At study end, the high rate of LCA had the greatest soil pH, EC and total K in the upper forest floor, but the HCA had greater total B, P and Zn. LCA elicited increased foliar B in pine, but HCA increased foliar Ca in spruce when co-applied with fertilizer N. In general, Douglas-fir growth did not respond to ash treatments, and seedling mortality was observed in some LCA treatments. Ash treatments helped offset some nutrient deficiencies induced by N fertilization. Ash type influenced soil chemical as well as seedling growth and nutrition responses.

While cover crops (CC) are known to enhance soil health, outcomes are often subtle and confined to a shallow surface soil layer. We assessed 15 soil health indicators over three CC trials with a 15-species Blend polyculture, a Mustard biculture (white (Sinapsis alba L.) and brown (Brassica juncea (L.) Czern.) mustards), Buckwheat (Fagopyrum esculentum Moench), and Faba bean (Vicia faba L.) monocultures, and a Weedy fallow (no CC, weeds allowed to grow) on an organic farm in southern Alberta. Soil sampling times included (i) summer pretermination; (ii) fall post-termination; and (iii) spring post-termination of CC. Twelve of 15 soil health indicators showed significant effects of CC treatment for at least one sampling time. Soil organic C (SOC) ranked highest with 80% of sampling times showing significant CC effects. N-related indicators (total N (TN), nitrate-N)) were also quite sensitive, being significantly affected by CC treatment at 60% of sampling times. Three soil health indicators (acid phosphomonoesterase (AcP), wet aggregate stability, and free-living nematodes (FLN)) were consistent in their nonresponses to CC treatment at all sampling times. Comparing CC treatments with a Weedy fallow, showed that not all enhancements of soil health were explained by inclusion of a CC, with Weedy fallow as effective for some indicators. A polyculture Blend significantly enhanced soil health over a monoculture CC or Weedy fallow in 46% of instances of soil health indicator improvement. While CC led to enhancement of soil health, results were not always consistent, being contingent on specific indicators.

Soil organic carbon (SOC) content is a key metric of soil quality and limited work has been done to examine the effect of long-term conservation agriculture management practices (CAMP) on SOC pools within western Canadian soils. We assessed the nature and permanence of sequestered SOC within 90 diverse Saskatchewan surface (0–10 cm) agricultural soils before and after 21 years of CAMP. Comparisons were made of total SOC, labile and dynamic SOC fractions (light fraction, water-extractable, and microbial biomass), respirable CO₂–C during a 6-week incubation, along with spectroscopic characterization using ¹³C/¹²C stable isotope ratio and ATR-FTIR. Among soil climatic zones, the SOC content increased in the semi-arid Brown and Dark Brown soils, ranging from 2.4 to 3.7 Mg C ha⁻¹ (111.4–187.7 kg C ha⁻¹ year⁻¹), but did not change in the subhumid Black, Dark Gray, and Gray soils. Overall, soils having the smallest initial SOC level were most responsive to CAMP and accumulated more SOC. According to the Δ¹³C data, CAMP appeared to reduce annual crop moisture stress, especially within the Brown soil zone. Decreased light fraction and water-extractable SOC contents in Black, Dark Gray, and Gray soils could reflect more intense decomposition and greater surface stratification of crop residues. Brown soils experienced the largest increase in microbial biomass-C content. The CO₂–C emissions from the Brown, Dark Brown, and Gray soils under CAMP suggest greater SOC stability in 2018 compared with 1996. The ATR-FTIR data pointed to enhanced SOC persistence, via more stabilized SOC forms and mineral-associated organic C fractions.

Arbuscular mycorrhizal fungi (AMF) play important roles in the dynamics of soil organic carbon (SOC), as they can promote its accumulation and the formation of soil aggregates, thereby increasing soil carbon storage. However, the impact of carbon input through AMF inoculation on SOC sequestration is still unclear. In this study, the effects of AMF on photosynthetic carbon transport and SOC accumulation in two types of black soils with either high or low SOC soils were analyzed by an outdoor pot experiment using isotope ¹³C labeling, thus, revealing the mechanism of action of AMF in stabilizing SOC fixation. The results showed that AMF symbiosis increased the allocation of photosynthetic carbon to the roots of the maize plant and soils. Inoculation with AMF also increased the proportions of soil macro-aggregates and the soil microbial biomass carbon content in low SOC soil, promoted the accumulation of soil aggregates, and enhanced the chemical composition of SOC. After returning the harvested labeled straw to the original pots the following year after planting, inoculation with AMF was found to increase the contents of hemicellulose and lignin at the time when maize kernels attained a plump appearance. AMF significantly increased glomalin-related soil protein in high SOC soil. In addition, AMF had a promoting effect on the decomposition of cellulose, hemicellulose, and lignin in the straw, which could subsequently increase the accumulation of carbon. We provide evidence for the promotion of soil aggregates, soil C accumulation, and SOC sequestration with AMF inoculation.

There is increasing interest in soil organic carbon (SOC) sequestration as a climate change mitigation strategy. There is a need to estimate the quantity of SOC sequestered historically due to no-till, and the remaining sequestration potential in Saskatchewan. To answer this question, predictive soil mapping results were linked with the Century model to predict SOC stock change over time to a depth of 20 cm considering three different future climate change scenarios. Climate scenarios included low, moderate, and high amounts of climate change and included estimated changes to monthly minimum, average, and maximum temperature, total monthly precipitation, and average monthly relative humidity at an 800 m × 800 m resolution. Historically, the modelled average SOC gain for Saskatchewan was 2.8 Mg ha⁻¹. Future potential simulated SOC was lower over the next 30 years, with average SOC gains estimated to range from 1.4 to 1.7 Mg ha⁻¹ by 2054 and 2.3 to 3.1 Mg ha⁻¹ by 2100. There is also unequal spatial distribution of SOC stock gain potential, with the northern grain growing regions showing lower future potential. The predicted future gains will be at a lower rate than in the past with carbon sequestration rates dropping from 0.06 to less than 0.02 Mg ha⁻¹ year⁻¹. Additional management practices such as improved residue management and the introduction of crop varieties with increased below ground carbon inputs and more stable residues should be explored to offset the diminishing SOC returns from no-till.

Soil disturbance, reduced crop diversity, and decreased residue in intensively managed systems can negatively impact soil biological communities and soil health. This study examined the impact of long-term (>20 years) low- (forest, grassland), medium- (diversified annual cropping), and high-intensity (annual cropping, frequently to potatoes) land-use on soil nematode communities and soil health in 59 sites across Prince Edward Island, Canada. Soil samples (0–15 cm) were collected at five locations per site and analysed for soil biological (nematode communities, respiration, soil organic matter, permanganate oxidizable carbon (POXc), soil protein), chemical (pH, N, soil N supply, extractable nutrients), and physical (bulk density, texture) properties. Soil pH and extractable nutrients were lowest in the low-intensity sites, while total C and C:N ratios were highest and decreased with increasing land-use intensity (low > medium > high). Soil respiration, POXc, and protein were lowest for high-intensity sites. Low-intensity sites had greater nematode Shannon diversity and richness, and higher maturity and structure indices than the medium- and high-intensity sites (p < 0.05), signifying a more structured nematode community. Nematode communities from the high-intensity sites were more degraded and had significantly higher basal indices compared to the low- and medium-intensity sites. At the trophic level, the low-intensity system had higher numbers of omnivores and lower abundance of bacterivores. These differences in nematode trophic composition may result in differences in ecosystem function, including nutrient cycling and biological control.

I offer this perspective as hope that miyo wîcêhtowin (translated as “good relations” in Plains Cree) can be established between the discipline of soil science and Indigenous Peoples in Canada. This perspective reflects not only on the difficult truths of why the relationship between Indigenous Peoples and soil science is primarily one of exploitation and neglect, but also on how fostering a relationship built on reciprocity presents opportunities for Indigenous knowledge systems and soil science to improve the way we relate to land and how we steward soil. Soil science was borne in this country as an instrument of colonization of the plains, marginalizing First Nations from their lands and livelihoods through agricultural settlement. It is necessary to illuminate this fraught history to understand the contemporary realities of First Nations in the prairies, including the hopeful efforts First Nations are making towards conservation and restoration of prairie landscapes—and revitalization of Indigenous knowledge systems—especially though buffalo rematriation. This sharing is done in the hope that we can collectively work towards reciprocity in the relationship between Indigenous Peoples and soil science as a discipline for improved caretaking of the land.

The H3A-4 extraction is a new method to determine plant available nutrients but has not been compared with standard soil tests or calibrated to crop response in Manitoba, Canada. Olsen P and ammonium acetate K were related to H3A-4 P and K for 961 soil samples. Significant relations were found between Olsen P and H3A-4 (R² = 0.74, P < 0.01) and ammonium acetate K and H3A-4 (R² = 0.83, P < 0.01). New thresholds were established for fertilizer recommendations with H3A-4 as 24 mg kg^–1 for P and 32 mg kg^–1 for K.

Geophysical methods like ground-penetrating radar (GPR) and electromagnetic induction (EMI) offer non-destructive, high-resolution alternatives for soil sampling. This study aims to understand subsurface stratifications in boreal podzolic soil employing an integrated GPR–EMI technique and soil sampling. The GPR and EMI confirmed each technique's findings. They provided insights into the spatial variability of electrical conductivity, textural changes, and stratification (detected mainly by GPR reflections) in the soil profile. The assessed soil properties revealed the existence of two contrasting layers within 0–0.60 m depth. The study highlights the potential of using integrated GPR–EMI to identify subsurface stratification in boreal podzolic soil.