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Item Recycling Olive Mill Wastewater to Calcareous Soil: Effect of Preplanning Application Period on Phytotoxicity, Corn Growth, and Nutrient Uptake(MDPI, 2025-02) Hasan, Yousef N. Y.; Ahmed, Ibrahim; Al-Barakah, Fahad; Schoenau, Jeffrey; Alotaibi, Khaled D.This study investigated the effects of applying olive mill wastewater (OMWW) at different periods prior to corn (Zea mays) sowing on germination rate (GR), growth, and soil nutrient availability in calcareous soil. The OMWW was applied at rates of 0, 20, 40, and 60 m3 ha−1 and was allowed to remain in soil for zero, one, two, three, or four months before sowing corn seeds. Immediate planting after OMWW application significantly reduced the GR, with rates of 83%, 75%, and 63% at 20, 40, and 60 m3 ha−1, respectively. Germination improved when corn was sown one month after OMWW application, with a GR of 92% at both 20 and 40 m3 ha−1 and 79% at 60 m3 ha−1. The GR increased to 96% for the 40 and 60 m3 ha−1 rates when OMWW was applied two months before planting. The adverse impact on GR disappeared when OMWW was in the soil for three months before sowing, providing a GR similar to the unamended control. Corn dry matter yield also improved when OMWW was applied two to three months before planting. The phytotoxic effects of OMWW, due to its high polyphenol content, diminished over time due to rapid degradation in calcareous soils. Soil available N and P were highest, and plant N, P, and K content increased, when OMWW was applied two months prior to planting. Soil pH decreased from 7.8 to 7.2 at 60 m3 ha−1 of OMWW at planting time. Results suggest that OMWW can enhance soil quality and corn growth if applied one to two months before planting to avoid possible negative impact on germination. This work bridges the gap between waste management and sustainable agriculture, offering practical guidelines for OMWW utilization.Item Phosphorus fertilizer responsive bacteria and fungi in canola (Brassica napus L.) roots are correlated with plant performance(Plant and Soil, 2025-02-17) Liu, Mengying; Mooleki, S. Patrick; Li, Yunliang; Schneider, Dave; Kochian, Leon V; Helgason, BobbiBackground Canola (Brassica napus L.) has high phosphorus demand, but its seedlings are sensitive to seed-placed phosphorus fertilizers. Optimizing phosphorus fertilizer management for canola is critical and can benefit from insights into the root-associated microbiota, which enhances phosphorus availability through mineralization and solubilization. Methods We conducted a two-year field experiment applying monoammonium phosphate fertilizer at three rates (no addition, recommended rate, and high rate at 0, 17, and 32 kg P ha−1 year−1) using two opener placements (narrow at 2.5 cm vs. wide at 10 cm). Canola performance was evaluated, and rhizosphere and root bacterial and fungal microbiota was profiled by DNA amplicon sequencing. Results High-rate and near-seed placement of phosphorus (32 kg P ha−1 in the 2.5 cm opener) reduced canola seedling emergence but not biomass or yield, which were higher in 2020 than in 2019. Yearly variations and plant growth stages impacted the rhizosphere and root microbiota, while phosphorus fertilization only affected the root microbiota. Phosphorus fertilization enriched Burkholderia-Caballeronia-Paraburkholderia, Luteibacter, Amaurodon, Trichoderma, and Penicillium in roots, Conversely, Chryseobacterium, Chitinophaga, Flavobacterium and Olpidium were more prevalent in roots without phosphorus addition. Yield positively correlated with the relative abundance of Burkholderia-Caballeronia-Paraburkholderia and Trichoderma in roots. Conclusions Phosphate fertilizer rates and placements affected canola germination but not yield. Profiling of phosphorus-responsive root microbes suggests that phosphate fertilizer rate and placement at seeding can have a lasting impact on the canola root microbiota as the plant matures, modulating plant growth responses to soil phosphorus availability.Item Thermodynamics of microbial decomposition of persistent carbon in erosion-buried topsoils(Soil Biology and Biochemistry, 2025-01) Mitchell, Amanda; Helgason, BobbiHillslope erosion in hummocky landscapes can lead to the accumulation of C-rich topsoil in depositional positions that eventually becomes buried if erosion persists. Our objective in this study was to evaluate the persistence of SOC and the thermodynamic efficiency of the microbial community in C-rich buried surface horizons from five sites with varied texture and organic matter contents. Surface Ah (0–10 cm) and buried surface (Ahb) horizons were isolated from intact cores, sieved (<2 mm) and incubated under ideal conditions of temperature and moisture. Ahb soils had an average organic C content (25.6 mg OC g−1 soil) similar to the corresponding Ah soil (30.9 mg OC g−1 soil). Using isothermal calorimetry, we determined that Ah horizons produced significantly more heat and CO2 but had smaller calorespirometric ratios than Ahb soils, under both basal (841 vs 3106 kJ mol−1 CO2–C) and glucose metabolism (627 vs. 697 kJ mol−1 CO2–C)0.100-day basal respiration was nearly four times greater in Ah vs. Ahb horizons. While MAOM correlated with basal heat production in both horizons, it only correlated with C persistence in the Ah horizons (Rho = 0.67, p < 0.01), suggesting variability in C persistence was not primarily driven by organo-mineral bonds in Ahb horizons, although energy use efficiency is. Microbial community structure in Ahb horizons was distinct from the surface soils, and changed minimally during incubation, suggesting co-development of the community as decomposition proceeded over the decades of burial, leading to persistent C. These relatively large volume buried surface soils may provide unique opportunities to understand microbial hotspot C processes that are typically difficult to isolate at a spatially explicit scale (e.g., an aggregate interior). We propose that the co-development of distinct microbial communities in C-rich buried horizons leads to more thermally stable SOC, but further research is required to test this hypothesis.Item Evidence of the need for crop-specific N2O emission factors(Soil Biology and Biochemistry, 2024-12) Shorunke, Akeem T.; Helgason, Bobbi; Farrell, RichardCrop residues are an important source of N for subsequent crops and contribute to cropping system nitrous oxide (N2O) emissions. Oilseed residues, particularly canola (Brassica napus L.), can instigate higher N2O emissions compared to pulse and wheat crop residues but the reason for this disproportionate emission response is unknown. To determine the quantity and source of N2O emissions, we conducted an incubation experiment (84 d) using 15N and 13C labelled residues of canola, wheat, flax, pea and investigated key N-cycling gene abundances, microbial abundance and community structure using PLFA and soil C and N dynamics. Residue addition of all types significantly increased microbial abundance and abundances of denitrification and nitrification genes. Canola residue resulted in significantly greater nosZI abundance. Lower incorporation of canola residue 13C into PLFA and higher 13CO2 emissions suggests that canola residue C was used less efficiently (i.e., less for growth and more for respiration), depleting O2 and stimulating denitrification. The magnitude of N2O emission from residue-amended soils was significantly higher (p < 0.05) than the unamended control soil and differed with residue type: canola > pea = wheat > flax > control. The canola residue emission factor was 1.56% of residue N – significantly higher than that of wheat (0.99%), pea (0.95%) and flax (0.18%). This higher canola emission factor resulted from greater residue-derived (1.47%) N2O as well as residue-induced (0.65%) soil emissions. The combined use of stable isotope tracing of 15N2O and 13CO2 and microbial characterization quantified differences in residue-derived N2O emissions from common crops that were linked to differences in microbial abundance, community structure and activity.Item Thermodynamics of Microbial Decomposition of Persistent Carbon in Erosion-Buried Topsoils(Soil Biology and Biochemistry, 2025) Mitchell, Amanda; Helgason, BobbiHillslope erosion in hummocky landscapes can lead to the accumulation of C-rich topsoil in depositional positions that eventually becomes buried if erosion persists. Our objective in this study was to evaluate the persistence of SOC and the thermodynamic efficiency of the microbial community in C-rich buried surface horizons from five sites with varied texture and organic matter contents. Surface Ah (0-10 cm) and buried surface (Ahb) horizons were isolated from intact cores, sieved (<2 mm) and incubated under ideal conditions of temperature and moisture. Ahb soils had an average organic C content (25.6 mg OC g-1 soil) similar to the corresponding Ah soil (30.9 mg OC g-1 soil). Using isothermal calorimetry, we determined that Ah horizons produced significantly more heat and CO2 but had smaller calorespirometric ratios than Ahb soils, under both basal (841 vs 3106 kJ mol-1 CO2-C) and glucose metabolism (627 vs. 697 kJ mol-1 CO2-C).100-day basal respiration was nearly four times greater in Ah vs. Ahb horizons. While MAOM correlated with basal heat production in both horizons, it only correlated with C persistence in the Ah horizons (Rho = 0.67, p < 0.01), suggesting variability in C persistence was not primarily driven by organo-mineral bonds in Ahb horizons, although energy use efficiency is. Microbial community structure in Ahb horizons was distinct from the surface soils, and changed minimally during incubation, suggesting co-development of the community as decomposition proceeded over the decades of burial, leading to persistent C. These relatively large volume buried surface soils may provide unique opportunities to understand microbial hotspot C processes that are typically difficult to isolate at a spatially explicit scale (e.g., an aggregate interior). We propose that the co-development of distinct microbial communities in C-rich buried horizons leads to more thermally stable SOC, but further research is required to test this hypothesis.Item Evidence of the need for crop-specific N2O emission factors(Soil Biology and Biochemistry, 2024-12) Shorunke, Akeem T; Helgason, Bobbi; Farrell, Richard ECrop residues are an important source of N for subsequent crops and contribute to cropping system nitrous oxide (N2O) emissions. Oilseed residues, particularly canola (Brassica napus L.), can instigate higher N2O emissions compared to pulse and wheat crop residues but the reason for this disproportionate emission response is unknown. To determine the quantity and source of N2O emissions, we conducted an incubation experiment (84 d) using 15N and 13C labelled residues of canola, wheat, flax, pea and investigated key N-cycling gene abundances, microbial abundance and community structure using PLFA and soil C and N dynamics. Residue addition of all types significantly increased microbial abundance and abundances of denitrification and nitrification genes. Canola residue resulted in significantly greater nosZI abundance. Lower incorporation of canola residue 13C into PLFA and higher 13CO2 emissions suggests that canola residue C was used less efficiently (i.e., less for growth and more for respiration), depleting O2 and stimulating denitrification. The magnitude of N2O emission from residue-amended soils was significantly higher (p < 0.05) than the unamended control soil and differed with residue type: canola > pea = wheat > flax > control. The canola residue emission factor was 1.56% of residue N – significantly higher than that of wheat (0.99%), pea (0.95%) and flax (0.18%). This higher canola emission factor resulted from greater residue-derived (1.47%) N2O as well as residue-induced (0.65%) soil emissions. The combined use of stable isotope tracing of 15N2O and 13CO2 and microbial characterization quantified differences in residue-derived N2O emissions from common crops that were linked to differences in microbial abundance, community structure and activity.Item Biochar Amendments to Improve Soil Phosphorus Fertility and Retention in Canadian Prairie Soils(Springer Link, 2024-09-06) Dannhauser, Anèl; Schoenau, Jeff J.; Hangs, Ryan D.; Patra, Biswa R.; Dalai, Ajay K.The utilization of biochar, a carbonaceous substance derived from pyrolysis, has been extensively investigated in various agricultural settings. However, applying biochar to Canadian prairie soils without additional fertilizer treatments generates minimal benefits for crop productivity. This study investigated the effects of biochar amendments, with and without addition of Triple Superphosphate (TSP) fertilizer, on phosphorus (P) availability and retention in Canadian prairie crops and soils. Specifically, the study assessed crop yield, P uptake and recovery by canola plants, soil P retention, infiltration rates and P losses in simulated snowmelt runoff. Controlled environment and field studies were conducted with biochar and TSP fertilizer on nutrient deficient soils in the Saskatchewan Brown and Black soil zones. Under both growth chamber and field conditions, biochar derived from canola hull, manure, and willow feedstocks were shown to contribute some available P for plant uptake, with observed recovery of biochar P by canola up to ca. 50% of that found for TSP fertilizer. Among these biochar feedstocks canola meal biochar was least effective in supplying plant available P in the year of application. Willow biochar applied alone, or co-applied with TSP, may be an effective strategy for reducing P losses in snowmelt runoff compared with TSP alone and willow biochar also contributed to increased water infiltration. Biochars can potentially benefit canola production by enhancing P nutrition and recovery. Moreover, a balance may be obtained between biochar supplying P during the growing season, while reducing P losses in the spring snowmelt runoff.Item Soil denitrification response to increased urea concentration constrains nitrous oxide emissions in a simulated cattle urine patch(Springer, 2023-05-24) Reimer, Jesse C.; Arcand, Melissa; Helgason, BobbiAim Incorporating non-bloat legumes into grass pastures can reduce enteric methane and alter cattle urinary urea N output by increasing protein intake. Deposition of high urea N urine influences soil N-cycling microbes and potentially N2O production. We studied how urine urea N concentration affects soil nitrifier and denitrifier abundances, activities, and N2O production. Methods 15N13C-labelled urea dissolved in cattle urine was added at 3.5 and 7.0 g L−1 to soils from a grazed, non-bloat legume pasture and incubated under controlled conditions. CO2, N2O, 13C-CO2, and 15N-N2O production were quantified over 240 h, along with nitrifier and denitrifier N-cycling genes and mRNA transcripts. Results High urea urine increased total N2O relative to the control; low urea was not significantly different from the control or the high urea treatment. As a result, N2O-N emission factors were not significantly different between the low urea treatment (1.17%) and high urea treatment (0.94%). Doubling urea concentration doubled CO2-Curea and N2O-Nurea but not total N2O-N. Urine addition initially inhibited then increased AOB transcripts and gene abundances. nirK and nirS transcript abundances indicated that denitrification by ammonia oxidizers and/or heterotrophic denitrifiers dominated N2O production. Urine addition increased nosZ-II vs. nosZ-I transcripts, improving soil N2O reduction potential. Conclusion Characterizing this interplay between nitrifiers and denitrifiers improves the understanding of urine patch N2O sinks and source dynamics. This mechanistic information helps to explain the constrained short-term N2O emissions observed in response to excess urine N excretion from cattle consuming high protein diets, e.g. non-bloat legumes.Item Land use in the Prairie Pothole Region influences the soil bacterial community composition and relative abundance of nitrogen cycling genes(Canadian Science Publishing, 2023) Town, Jennifer; Yu, Min; Lemke, Reynald; Helgason, BobbiThe undulating topography of Prairie Pothole Region of North America creates spatial and temporal variability in soil moisture and nutrient levels, affecting microbial community processes and greenhouse gas emissions. By identifying differences in soil bacterial and archaeal community composition and the abundance of nitrogen cycling genes in permanent cover versus annual crop land over two growing seasons (2017 and 2018), we were able to assess the effects of topography and land use on the functional capacity of the soil microbiome. Permanent grassland cover was associated with higher bacterial diversity in upland positions and lower diversity in low-lying depressions. Bacterial community composition was also significantly different between cultivated and permanent cover at all points along the topographic slope, with the largest effects seen in the footslope and backslope positions. Compared to permanent cover, soil from annual cropland had consistently more abundant nitrifiers, including Nitrospira in the toeslope and backslope, and Nitrososphaeraceae in the shoulder and knoll samples while soils from permanent cover had a greater abundance of several Alphaproteobacteria from Rhodospirillales and Hyphomicrobiaceae across multiple upland positions. Upland soils from annual cropland also had consistently higher abundance of both bacterial and archaeal ammonia oxidizing (amoA) genes and a higher ratio of nirK:nirS genes compared to those from permanent cover. These differences in microbial community composition were associated with higher N2O and CO2 emissions in upland soils in annual cropland; however, there were no differences in GHG emissions between the two systems in low-lying positions.Item Contrasting Nitrogen Fertilization and Brassica napus (Canola) Variety Development Impact Recruitment of the Root-Associated Microbiome(APS Publications, 2023) Li, Yunliang; Vail, Sally L.; Arcand, Melissa M.; Helgason, BobbiCanola (Brassica napus) is an important broadacre crop, produced under high nitrogen (N) fertilizer application. Modern canola varieties are developed under high N rates but the impacts on root-associated microbiomes of different varieties are unknown. We studied eight canola varieties spanning historical Canadian spring canola development at two sites under high and low N fertility and characterized bacterial and fungal microbiomes in the root and rhizosphere using amplicon sequencing. Environmental conditions and the resulting canola varietal responses strongly affected the root-associated bacterial and fungal microbiomes. Microbes regulated by N fertility in each canola variety were mainly Gammaproteobacteria, Bacteroidia, Actinobacteria, Sordariomycetes, Dothideomycetes, and Agaricomycetes classes. Differentially abundant (DA) microbial taxa showed that N more strongly enriched bacteria in the roots and fungi in the rhizosphere. Each variety had its specific pattern of DA amplicon sequence variants (ASVs) responding to soil N availability, and the profile of DA-ASVs in paired canola varieties were also altered by soil N availability, especially bacteria in the rhizosphere. The yield was strongly associated with a subset of microbial taxa, mainly from Proteobacteria, Actinobacteriota, and Ascomycota. These variety-dependent responses to N and links to yield performance make the root-associated microbiome a promising target for improving the agronomic performance of canola by manipulating microorganisms tailored to soil fertility and plant genotype.Item Crop rotation significantly influences the composition of soil, rhizosphere, and root microbiota in canola (Brassica napus L.)(BMC (part of Springer Nature), 2023) Town, Jennifer R.; Dumonceaux, Tim; Tidemann, Breanne; Helgason, BobbiBackground: Crop rotation is an agronomic practice that is known to enhance productivity and yield, and decrease pest and disease pressure. Economic and other factors have increased the frequency of certain crops, including canola, with unknown effects on the below ground microbial communities that impact plant health and performance. This study investigated the effect of 12 years of crop rotation including canola-wheat; canola-pea-barley; and unrotated canola across three geographic sites in Western Canada with diverse soil types and environmental conditions. To provide data on mature, established crop rotation strategies, root exudate profiles, soil nutrient fluxes, and bacterial and fungal microbial community profiles were determined at the flowering stage in the final two (canola) years of the 12-year rotations. Results: After 12 years of rotation, nutrient fluxes were affected in the soil in an inconsistent manner, with K, NO3, Mg, Ca, P, and Fe fluxes variably impacted by rotation depending on the year and site of sampling. As expected, rotation positively influenced yield and oil content, and decreased disease pressure from Leptosphaeria and Alternaria. In two of the three sites, root exudate profiles were significantly influenced by crop rotation. Bacterial soil, root, and rhizosphere communities were less impacted by crop rotation than the fungal communities. Fungal sequences that were associated with specific rotation strategies were identified in the bulk soil, and included known fungal pathogens in the canola-only strategy. Two closely related fungal sequences identified as Olpidium brassicae were extremely abundant at all sites in both years. One of these sequences was observed uniquely at a single site and was significantly associated with monocropped canola; moreover, its abundance correlated negatively with yield in both years. Conclusions: Long-term canola monoculture affected root exudate profiles and soil nutrient fluxes differently in the three geographic locations. Bacterial communities were less impacted by rotation compared to the fungal communities, which consistently exhibited changes in composition in all ecological niches at all sites, in both years. Fungal sequences identified as O. brassicae were highly abundant at all sites, one of which was strongly associated with canola monoculture. Soil management decisions should include consideration of the effects on the microbial ecosystems associated with the plants in order to inform best management practices.Item A 1000-Year Record of Temperature From Isotopic Analysis of the Deep Critical Zone in Central China(Wiley Open Access [Commercial Publisher]; American Geophysical Union [Client Organisation], 2023) Wang, Hongxiu; Li, Han; Xiang, Wei; Lu, Yanwei; Wang, Huanhuan; Hu, Wei; Si, Bing Cheng; Jasechko, Scott; Mcdonnell, JeffreyTemperature proxies for paleoclimate reconstruction have been made typically via ice cores, tree rings, stalagmites, and lake sediments. While extremely useful, these proxies can be limited spatially. Here we sampled a 98 m “soil core” from Loess Plateau of China and examined the relationship between pore water isotopic values and hydroclimate history. We extracted soil pore water for δ 18O, δ 2H, and 3H and measured chloride concentration. The 3H-peak at 6 m and chloride mass balance were used to turn depth into calendar year. A 1000 year span was revealed. δ 18O and δ 2H values between 14–50 m were anomalously low—bracketing well the Little Ice Age period from 1420 to 1870. The identification was consistent with other standard proxies in the region and showed the same temporal dynamics of temperature anomalies. Our study shows the potential of stable isotopes of soil water for paleoclimate reconstruction in deep soils.Item Spatiotemporal Variation in Driving Factors of Vegetation Dynamics in the Yellow River Delta Estuarine Wetlands from 2000 to 2020(MDPI, 2023) Niu, Zhongen; Si, Bing Cheng; Li, Dong; Zhao, Ying; Hou, Xiyong; Li, Linlin; Wang, Bin; Song, Bing; Zhang, Mengyu; Li, Xiyu; Zeng, Na; Zhu, Xiaobo; Lv, Yan; Mai, ZiqiPrevious studies of vegetation dynamics in the Yellow River Delta (YRD) predominantly relied on sparse time series or coarse-resolution images, which not only overlooked the rapid and spatially heterogeneous changes, but also limited our understanding of driving mechanisms. Here, employing spatiotemporal data fusion methods, we constructed a novel fused enhanced vegetation index (EVI) dataset with a high spatiotemporal resolution (30-meter and 8-day resolution) for the YRD from 2000 to 2020, and we analyzed the vegetation variations and their driving factors within and outside the YRD Nation Natural Reserve (YRDNRR). The fused EVI effectively captured spatiotemporal vegetation dynamics. Notably, within the YRDNRR core area, the fused EVI showed no significant trend before 2010, while a significant increase emerged post-2010, with an annual growth of 7%, the invasion of Spartina alterniflora explained 78% of this EVI increment. In the YRDNRR experimental area, the fused EVI exhibited a distinct interannual trend, which was characterized by an initial increase (2000–2006, p < 0.01), followed by a subsequent decrease (2006–2011, p < 0.01) and, ultimately, a renewed increase (2011–2020, p > 0.05); the dynamics of the fused EVI were mainly affected by the spring runoff (R2 = 0.71), while in years with lower runoff, it was also affected by the spring precipitation (R2 = 0.70). Outside of the protected area, the fused EVI demonstrated a substantial increase from 2000 to 2010 due to agricultural land expansion and human management practices, followed by stabilization post-2010. These findings enhance our comprehension of intricate vegetation dynamics in the YRD, holding significant relevance in terms of wetland preservation and management.Item Characterization of problem soils in and around the south central Ethiopian Rift Valley(Academic Journals, 2016) Alemayehu, Kiflu; Sheleme, Beyene; Schoenau, JeffreySome soils in Ethiopia reduce plant productivity due to physical and/or chemical limitations. The morphological, physical and chemical properties of problem soils, including sodic, acidic, and saline soils, around southern Ethiopia were characterized and are described in this chapter. The intention is to characterize the soils and better understand the specific nature of the limitations. Sodic soils of Alage, acid soils of Hagereselam, and saline soils of Zeway areas were sampled to represent the problem soils. The soil properties determined included color, electrical conductivity (EC), structure, consistency, bulk density, texture, pH, organic carbon (OC), total nitrogen, available phosphorus (P) and K, exchangeable bases and available micro-nutrients. The soils had considerable heterogeneity in solum and regolith thickness, horizon depth, structural development in surface soils and subsurface horizons, pH, EC and available nutrients. The classification of these soils was made according to Soil Taxonomy and World Reference Base for Soil Resources systems. The sodic soils of Alage had high pH and sodium (Na) content, and low level of OC, available P, copper (Cu) and zinc (Zn). The epipedon was classified as an ochric and the profile also had variation in clay content down the profile to satisfy the requirements of having an argilic horizon and therefore these soils were classified as Typic Natragids. Soils of Hagereselam had very low available P. Available Cu and Zn contents were found to be at the marginal levels for production of most crops. The Hagereselam profile had an argilic horizon with umbric epipedon and was classified as Typic Paleustults. The saline soils in Zeway area had relatively high amounts of calcium and low OC. The profile was found to have ochric epipedon and these soils are classified as Typic Haplocambids. Application of fertilizer including P, Cu and Zn, and removal of sodium and salts from the soil profile may be means of improving the productivity of these soils. Application of organic amendments including manures and crop residues may also be beneficial in increasing the fertility as well as organic carbon content.Item Addition of Biochar to a Sandy Desert Soil: Effect on Crop Growth,Water Retention and Selected Properties(MDPI, 2019) Alotaibi, Khaled D.; Schoenau, JeffreyAgricultural and environmental applications of biochar (BC) to soils have received increasing attention as a possible means of improving productivity and sustainability. Most previous studies have focused on tropical soils and more recently temperate soils. However, benefits of BC addition to desert soils where many productivity constraints exist, especially water limitations, have not been widely explored. Thus, three experiments were designed using a desert soil from Saudi Arabia to address three objectives: (1) to evaluate the effect of BCs produced from date palm residues added at 8 t ha−1 on wheat growth, (2) to determine the effect of BC addition and BC aging in soil on water retention, and (3) to reveal the effect of BC on selected soil physical (bulk density, BD; total porosity; TP) and chemical (pH; electrical conductivity, EC; organic matter, OM; cation exchange capacity, CEC) properties. The feedstock (FS) of date palm residues were pyrolyzed at 300, 400, 500, and 600 °C, referred to here as BC300, BC400, BC500, and BC600, respectively. The BC products produced at low temperatures were the most effective in promoting wheat growth when applied with the NPK fertilizer and in enhancing soil water retention, particularly with aging in soil, whereas high -temperature BCs better improved the selected soil physical properties. The low-temperature BCs increased the yield approximately by 19% and improved water retention by 46% when averaged across the incubation period. Higher water retention observed with low-temperature BCs can be related to an increased amount of oxygen-containing functional groups in the low-temperature BCs, rendering BC surfaces less hydrophobic. Only the BC300 treatment showed a consistent positive impact on pH, OM, and CEC. Pyrolysis temperature of date palm residue along with aging are key factors in determining the potential benefit of BC derived from date palm residues added to sandy desert soil.Item Demonstration and Testing of the Improved Shelterbelt Component in the Holos Model(Frontiers Media SA, 2020) Kröbel, Roland; Moore, Julius; Ni, Yu Zhao; McPherson, Aaron; Poppy, Laura; Soolanayakanahally, Raju Y.; Amichev, Beyhan Y.; Ward, Tricia; Laroque, Colin; Rees, Ken C. J. Van; Akhter, FardausiThe shelterbelt component of Canada’s whole-farm model Holos was upgraded from an age-determined to a circumference-determined (at breast height) calculation using a multi-stem averaging approach. The model interface was developed around the idea that a shelterbelt could have multiple rows, and a variable species composition within each row. With this, the model calculates the accumulated aboveground carbon in the standing biomass and a lookup table of modeled tree growth is used to add estimates of the belowground carbon. Going from an initial interface that asks for the current state, the model also incorporates an option of past and future shelterbelt plantings. In order to test the model’s suitability, we measured diverse shelterbelts (evergreen, deciduous, shrub type) in southern Saskatchewan, Canada representing commonly planted woody species. By making use of Caragana, Green Ash, Colorado Spruce, Siberian Elm, and a mixed Caragana/Green Ash tree row, we tested how many tree circumference measurements would be required to yield a representative average. Later, these results were incorporated in the Holos model to estimate the accumulated above-and below-ground carbon in each shelterbelt type.Item Multi-Horizon Predictive Soil Mapping of Historical Soil Properties Using Remote Sensing Imagery(MDPI, 2022) Sorenson, Preston; Kiss, Jeremy; Bedard-Haughn, Angela; Shirtliffe, SteveThere is increasing demand for more detailed soil maps to support fine-scale land use planning, soil carbon management, and precision agriculture in Saskatchewan. Predictive soil mapping that incorporates a combination of environmental covariates provides a cost-effective tool for generating finer resolution soil maps. This study focused on mapping soil properties for multiple soil horizons in Saskatchewan using historical legacy soil data in combination with remote sensing band indices, bare soil composite imagery, climate data, and terrain attributes. Mapped soil properties included soil organic carbon content (SOC), total nitrogen, cation exchange capacity (CEC), electrical conductivity (EC), inorganic carbon (IOC), sand and clay content, and total profile soil organic carbon stocks. For each of these soil properties, a recursive feature elimination was undertaken to reduce the number of features in the overall model. This process involved iteratively removing features such that random forest out-of-bag error was minimized. Final random forest models were built for each property and evaluated using an independent test dataset. Overall, predictive models were successful for SOC (R2 = 0.71), total nitrogen (R2 = 0.65), CEC (R2 = 0.46), sand content (R2 = 0.44) and clay content (R2 = 0.55). The methods used in this study enable mapping of a greater geographic region of Saskatchewan compared to those previously established that relied solely on bare soil composite imagery.Item 1981 Soil Plant Nutrient Research Report(Department of Soil Science, University of Saskatchewan, Saskatoon, SK, 3/1/1982) Henry, J.L.; Hogg, T.J.Item 1980 Soil Plant Nutrient Research Report(Department of Soil Science, University of Saskatchewan, Saskatoon, SK, 3/1/1981) Henry, J.L.; Hogg, T.J.Item 1979 Soil Plant Nutrient Research Report(Department of Soil Science, University of Saskatchewan, Saskatoon, SK, 3/1/1980) Henry, J.L.; Hogg, T.J.