Cropland soil is a major driver of global nitrous oxide (N₂O) emissions. In cold climates, nongrowing season (NGS) emissions can be significant due to high fluxes during freeze–thaw (FT) cycles. Cover crops can alter key soil conditions that govern N₂O-producing microbial processes, with multiple potential pathways to either increase or decrease N₂O production during FT cycles. Cultivating cover crops in the fall to terminate may further disrupt these processes and the overall impact of cover crops on N₂O emissions. Yet, few studies have touched on how termination practices of cover crops impact FT emissions over the NGS. Using the flux gradient method to continuously measure N₂O emissions from a conventional corn–soybean rotation, we investigated the effects of summer-established cover crops (perennial ryegrass and crimson clover) (with cover crops, +CC; without cover crops, −CC) when terminated by fall cultivation (with fall cultivation, +FC; without fall cultivation, −FC) over a six-month NGS that was characterized by several freezing and thawing periods. Crimson clover cover crop was completely winterkilled, while the ryegrass survived on the +CC−FC field. Total NGS (Nov–Apr) emissions varied nearly 2.5-fold among treatments from 395.1 (−CC−FC) to 978.1 (+CC+FC) g N₂O-N ha⁻¹. Compared with the control treatment (−CC−FC), fall cultivation alone (−CC+FC) and cover crops alone (+CC−FC) increased total NGS N₂O emissions, and fall cultivation with cover crops (+CC+FC) increased N₂O fluxes even more. Careful CC species selection and management are important to avoid elevated NGS emissions.

This 3-year meso-scale greenhouse study used 55-gallon columns to evaluate the survival and growth of boreal wetland communities planted on centrifuge (CF) tailings and co-mixed (CM) tailings capped with different reclamation cover soil capping designs. The CF tailings were capped with a shallow layer (10 and 30 cm) of peat reclamation material (PRM) and the CM tailings were capped with a shallow layer (5 cm) of PRM above 15 or 35 cm of reclamation subsoil (till). After 3 years, plant survival and growth on CF tailings showed significant improvement with a 10 cm PRM cap compared to the uncapped tailings, and plants growing on a 30 cm PRM cap outperformed those on the 10 cm PRM cap. Plant growth on CM tailings was significantly improved with a soil cover containing 5 cm PRM and at least 15 cm till. Among the seven native wetland species included in this study, the top performing species in terms of survival and above-ground biomass were Salix bebbiana, Scirpus microcarpus, and Carex aquatilis.

Diversification of conventional cereal-based cropping systems with pulse crops may aid producers to grow crops in an appropriate sequence and frequency with environmental, social, and economic benefits. This study examined the effects of including three pulse crops with different rooting depths (shallow- and deep-rooted) in wheat-based crop rotations on soil aggregate size distribution under semi-arid and rain-fed conditions. A 4 year cycle rotational study was established in Brooks, AB, using five selected treatments: continuous wheat, wheat alternately grown with lentil, field pea, or chickpea, or lentil and chickpea alternately grown with wheat. Soils were collected from 0–5 cm depth and dry-sieved to produce eight aggregate size classes, <0.053, 0.053–0.125, 0.125–0.149, 0.149–0.05, 0.05–1.0, 1.0–2.0, 2.0–6.35, and >6.35 mm. The continuous wheat treatment improved the macro-aggregates (>6.35 mm) development, whereas the rotations with pulse–wheat crops increased the micro- and meso-aggregates (0.50–1.0 and 0.15–0.5 mm) development. Soils sampled at 0–15 cm depth were used for soil organic matter and microbial analysis. The pulse–wheat rotations collectively had more light fraction organic matter (LFOM) than the continuous wheat, and chickpea alternated with wheat had the highest amount of LFOM in both years. All treatments had similar soil microbial biomass and microbial community composition. Our study underscores the contribution of pulse crops in cereal-based cropping systems in the formation of small aggregates.

This 3 year meso-scale greenhouse study used 55 gallon columns to evaluate the survival and growth of boreal upland and wetland communities on thickened tailings (TT) with 0 cm, 10 cm, and 30 cm peat mineral mix (PMM) reclamation cap. While survival was high in all treatments, the PMM cap treatments showed significant improvement in overall plant growth, cover, and above-ground biomass compared to the uncapped treatment, with growth on the 30 cm PMM cap outperforming the 10 cm PMM cap. The plant growth response was similar between the two communities and the top performing species, in terms of survival and growth, in capped TT were Cornus sericea, Populus tremuloides, Salix bebbiana, and Scirpus microcarpus.

Adoption of soil health indicators to assess physical, biological, and chemical properties involves adapting their interpretation for a specific region using scoring functions. Accordingly, we used data provided from 1166 soil samples distributed between fine-, medium-, and coarse-textured soils, collected in agricultural areas across the province of Quebec, Canada, and analyzed for 15 soil health indicators. Scoring functions were calculated according to the means and standard deviations obtained for each soil health indicator by textural group. Three scoring types were used: “more-is-better”, “less-is-better”, and “optimum-is-best”. The results showed that 12 indicators were significantly influenced by soil texture and need separate scoring functions, except for wet aggregate stability, penetration resistance of the surface hardness (0–15 cm), and pH. This led to the development of one to three scoring functions for each soil health indicator. Correlation analysis between soil health indicators was also investigated to better understand relationships between soil physical, biological, and chemical properties. We observed that soil biological indicators were moderately to strongly correlated with each other (r = 0.59–0.74) and with soil physical indicators (r = 0.60–0.76). Overall, the results of this study led to the development of new scoring functions based on soil texture to interpret soil health indicators objectively and accurately for the benefit of Quebec farmers and agricultural stakeholders. The findings of this study demonstrated the need to adapt scoring functions to better account for the impact of regional factors on agricultural soils for the interpretation of soil health indicators.

To reveal the mechanisms of straw mulching amounts and mulching periods on soil moisture in the black soil zone of Northeast China. Three types of straw mulching (0.4, 0.8, and 1.2 kg/m²) and two mulching periods (sowing stage and three-leaf stage) were set up as interactive experiments, and no straw mulching was used as the control (CK) to analyze the response mechanisms of soil moisture content, water consumption, and water use efficiency to straw mulching periods and mulching amounts at different depths. The results showed that straw mulching improved the moisture storage capacity compared with no straw mulching, and the straw mulching rate of 0.8 kg/m² at the three-leaf stage improved the moisture storage capacity and reduced the water consumption capacity compared with the straw mulching at the sowing stage, CK and other straw mulching treatments at the three-leaf stage; the crop yield and water use efficiency increased and then decreased with the increase of straw mulching. The increase of crop yield and water use efficiency under the straw mulching treatments at the three-leaf stage was higher than that under the same straw mulching treatments at the sowing stage. The analysis of the dual effects of straw mulching amounts and mulching periods on moisture gain and loss showed that the straw mulching amounts of 0.8 kg/m² at the three-leaf stage had the best effect on soil moisture characteristics and water use efficiency.

Yield decline in wheat grown after wheat is frequently attributed to fungal disease occurrence, but it is also found without visible disease infection. Thus it is hypothesized that other factors such as N supply or soil structural degradation may lead to wheat yield decline when grown after wheat. The aims of this study were to analyze if (i) the crop rotational position of winter wheat causes differences in soil structure at the beginning of the growing season and (ii) the soil structure is related to differences in wheat biomass formation by this date. Different soil structural properties under winter wheat as well as total aboveground biomass of wheat grown in different crop rotational positions (monoculture, first, second and third wheat after oilseed rape) were investigated in two long-term field experiments with contrasting soil texture. At both field sites, no significant effect of the crop rotational position in any of the analyzed soil structural parameters was found. Wheat biomass in spring was on average 54% higher for wheat grown after oilseed rape compared to second and third wheat after oilseed rape or monoculture. In conclusion, growth reduction of wheat cultivated after wheat was not linked to soil structure as measured in spring.

Red mud, a solid waste of alumina extraction from bauxite, was used as a compost carrier to prepare a geological fertilizer. It was amended at proportions of 0, 5%, 10%, 15% and 50% by weight (g/kg) to improve a rocky desertification soil (classified as lime soil) productivity. Through the simulation of different rain intensity (15, 50, and 90 mm/h) with three precipitation rates (1000, 2000, 3000 mm), soil chemical and physical properties, such as soil organic matter (SOM), total nitrogen (TN), ammonia nitrogen (AN), nitrate nitrogen (NN), total potassium (TK), available potassium (AK), total phosphorus (TP), available phosphorus (AP), bulk density and aggregates were tested and analyzed. In addition, a three-dimensional evaluation and analysis of the improvement attributed to the geological fertilizer was conducted. The results showed that the soil loss could be maintained in the range of 19%–72% under rainfall intensities. In addition, the reduction rate of soil clay content was less than 20%, and the lowest reduction rate of SOM, TN, TP and other nutrient was only 4% at the application rate of 5%–50%. The BD of the 0–20 cm top soil decreased progressively from 1.2 to 0.9 g/cm³, while the water-stable aggregate volume increased by 45%–76%. The red mud-based fertilizer enhanced the ability of the rocky desertification soil to resist rainfall erosion and infiltration in amended soil profiles. Considering the trends of nutrient losses and effects on the soil structure, the application rate of 15% by weight (g/kg) was best for improving the rocky desertification soil productivity.

Understanding the distribution of cations in forest soils is important for forest management. Here, we evaluated the leaching of cations, potassium (K⁺), sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), iron (Fe³⁺), aluminium (Al³⁺), and manganese (Mn²⁺), from litter through soils in two forest stands with different tree species. We incubated Castanopsis carlesii leaf litter in a Castanopsis carlesii stand and Cunninghamia lanceolata needle litter in a Cunninghamia lanceolata stand using a microcosm method with monthly collections of litter and soil leachates, and the concentrations of cations and fluxes of these cations were assessed separately. We found more Ca²⁺ but less Na⁺, Mg²⁺, and Fe³⁺ fluxes in litter leaching solutions in Cunninghamia lanceolata than in Castanopsis carlesii stand because of their different initial concentrations in fresh litter. Although cations leached from leaf litter differed among tree species, the leaching fluxes did not vary between stands. Moreover, annual fluxes of cations leached from soils were significantly higher than those from leaf litter, leading to a net loss of soil nutrients to downstream environment. Therefore, the results suggest that reforestation with mixed stands by introducing broadleaved trees in Chinese fir monoculture plantations might reduce soil nutrient loss through the leaching pathway.

The objectives of this study were to quantify long-term tillage practice and nitrogen (N) fertilizer rate effects on yield and N use in a winter wheat (Triticum aestivum L.)–grain sorghum (Sorghum bicolor L. Moench)–fallow (W–S–F) rotation. The experimental design was a randomized complete block with a split–split-plot arrangement. The main plot treatments were crop rotation phases W–S–F, S–F–W, and F–W–S. The sub-plots were tillage practices, i.e., conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). And the sub-sub-plot treatments were N rates of 0, 45, 90, and 134 kg ha⁻¹. Wheat yield increased at rates of 15.6, 9.3, 22.8, and 25.7 kg ha⁻¹ for a kg N ha⁻¹ increase in very low-, low-, high-, and very high-yielding environments (average yields of ∼2000, 2500, 2800, and 4400 kg ha⁻¹), respectively. On average, winter wheat yields were 7%–9% greater for CT compared with both NT and RT. Winter wheat removed about 52 kg N ha⁻¹ from the unfertilized control treatment, but N uptake varied by N rate and growing conditions. Nitrogen use efficiency, N agronomic efficiency, and applied N recovery decreased as the N rate increased. Across environments, wheat yield increased by 16, 20, and 17 kg ha⁻¹ for each additional kg ha⁻¹ N applied under CT, NT, and RT, respectively, and additional 2–2.5 kg ha⁻¹ yield increases for a mm increase in fallow precipitation. We concluded that wheat yield response to N is highly dependent on growing conditions, and NT required greater N fertilization than CT and RT for similar yields.

Soil protein is an important indicator of soil health and for soil health assessments is usually determined using autoclaved citrate extraction (ACE) followed by protein quantification using the Bradford or bicinchoninic acid assay. Here, we investigated an alternative extraction process using microwave-assisted citrate extraction. We show that protein yield increases as the extraction time increases, but that yields comparable to those obtained using the standard ACE method can be obtained with an extraction time as short as 15 min. To the best of our knowledge, this is the first report of microwave-assisted extraction being used to determine this soil protein pool.