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The use of biochar as a soil amendment for acid soil, particularly acid sulfate soil, has garnered significant interest due to its capacity to improve soil properties, which is further accentuated when combined with dolomite. However, the extent to which the magnitude and direction of this effect vary with biochar produced at different pyrolysis temperatures remains uncertain. We conducted an incubation by mixing soil with dolomite and biochar types derived from Melastoma malabathricum (MMBC) and Dicranopteris linearis (DLBC) at three temperatures (300, 500, and 700°C). The incorporation of dolomite with both biochar types led to significant improvements in soil pH, available P, available Fe, exchangeable K, and exchangeable Ca compared to soil amended with dolomite only. These enhancements were likely attributed to the release of alkalinity, which further raised soil pH, as well as the direct dissolution of P, K, and Ca from the biochar. Moreover, the reduced Fe availability was likely due to the complexation of Fe onto surface functional groups of biochar. Furthermore, these improvements surpassed the effect of the initial feedstock and became increasingly pronounced with higher pyrolysis temperatures. However, an antagonistic effect of dolomite and biochar co‐incorporation was observed, particularly in the relative reduction of soil exchangeable Mg with both biochar types, and a decrease in the soil available N with MMBC produced at 300 and 500°C compared to dolomite addition alone, which could be due to the adsorption of Mg and N onto biochar surface. The results indicate that concurrent application of dolomite and biochar can change the acid sulfate soil properties to varying magnitudes and in different directions, largely regulated by the characteristics of biochar as well as the probable interplay with dolomite. Consequently, selecting the appropriate biochar that aligns with the desired soil properties is crucial in managing dolomite‐treated acid sulfate soil. [ABSTRACT FROM AUTHOR]

Yield and quality improvements in Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) are increasingly difficult to attain, which behooves a systems approach to unlock genotype (G) × environment (E) × management (M) synergies. This 25 site-year study was designed to assess a G × E × M systems approach to improve CWRS agronomics, quality, and N use efficiency (NUE). The investigation consisted of genetics (AAC Viewfield vs. AC Stettler), N source (untreated urea; urea + urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor (NBPT + dicyandiamide); and polymer-coated) and N timing/placement (all-banded at planting, two-split applications and three-split applications), deployed across diverse soil zones in western Canada. Differential yield responses were observed between cultivars as AAC Viewfield produced superior yield over AC Stettler (+4.3%) in black and grey soils, while yield attainment was similar in dark brown soils. Genetic improvement over AC Stettler seemed most apparent in water abundant environments; however, AC Stettler was often superior in drier conditions. All N sources produced comparable outcomes for yield, quality, NUE, and net returns. In black and grey soils, adopting either all-banded or two-splits improved grain yield due to augmented seedling vigor, heads per plant, and N recovery. The timing of split-applications introduces more risk to yield and is likely attributed to a poorly developed source:sink relationship in the critical growth period if applied late to optimize grain protein. This highlights the complexity of the system and balance needed to harness the potential synergy between G, E, and M components. [ABSTRACT FROM AUTHOR]

Granular urea fertilizer applied at planting is prone to nitrogen (N) losses in certain environments. Enhanced efficiency fertilizers (EEFs) are developed to mitigate losses and optimize plant uptake. To determine the benefits of EEFs in grain yield and quality enhancement in Canada Western Red Spring (CWRS) wheat, an experiment was conducted from 2019 to 2022 at eight sites in Alberta and Saskatchewan, Canada. The effects of five N sources [urea; urea + urease inhibitor, N-(n-butyl)thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor, NBPT + dicyandiamide; and polymer-coated urea, ESN® (Environmentally Smart Nitrogen®)] and four N rates (60, 120, 180, and 240 kg N ha−1) on CWRS wheat production were examined. Results indicated that N source affected grain yield in Dark Brown Chernozem soils but not in Black Chernozem or Dark Grey Luvisol soils. In Dark Brown Chernozem soils, a dual inhibitor increased grain yield by 3.1% and 3.9% relative to urea and polymer-coated urea, respectively, while all other EEFs attained similar results. The use of a dual inhibitor EEF led to greater net returns compared to urea and polymer-coated urea in the Dark Brown Chernozem soils. Grain protein concentration increased linearly with increasing N rate from 60 to 240 kg N ha−1. Generally, a rate of 120 kg N ha−1 was optimal for CWRS wheat grown in Canadian prairie conditions when coupled with EEFs, particularly a dual inhibitor, and grain yield and protein were often responsive. [ABSTRACT FROM AUTHOR]

Minimizing tillage has been promoted as an agricultural practice that may mitigate greenhouse gas emissions through carbon sequestration. However, there is some ambiguity regarding the effect of minimum tillage (MT) on emissions of other greenhouse gases, in particular soil nitrous oxide (N2O) emissions. To determine how effective MT could be in helping Canada mitigate greenhouse gas emissions, we used a meta-analysis to compare growing season N2O emissions from MT versus conventional tillage (CT). Overall, MT had 12% lower N2O emissions compared to CT (P = 0.03). However, there was high variability due to soil texture and growing season precipitation (GSP), with MT tending to emit more N2O than CT in climates where GSP exceeded 600 mm, particularly for soils with sand content less than 60%. Therefore, unless long-term tillage trials, which are urgently needed in eastern Canada, show a reduction in N2O emissions over time, MT should be used as a greenhouse gas mitigation measure only in dry climates or on sandy soils. [ABSTRACT FROM AUTHOR]

Amending soil with manure from cattle fed biochar (BC) (biochar–manure [BM]) is a potential best management practice to improve plant nutrition in the circular economy. Yet, information concerning the agronomic performance of BM under temperate field conditions is scarce. A 2‐year study on a Gray Luvisol was conducted to determine the effect of BM on the crop growth of spring wheat (Triticum aestivum L.), followed by canola (Brassica napus L.), soil fertility, and microbial function. Treatments included (i) no amendments (control), (ii) BC at 5 and 10 Mg·ha−1 (BC5 and BC10), (iii) regular stockpiled manure (RM) at 100 kg total N·ha−1, (iv) stockpiled BM at 100 kg total N·ha−1, and (v) BC and RM (BC+RM) or BC and BM (BC+BM) at the aforementioned rates. During the wheat growing season in 2020, which had high precipitation, grain yield was 2.4 times greater in BM+BC10 than in BM alone (1416 vs. 579 kg·ha−1, p < 0.001), highlighting synergistic effects of BM together with BC application on agronomic performance. Conversely, lower precipitation and warmer temperatures in the canola growing season in 2021 hampered any statistical differences among treatments. While soil microbial biomass did not change by the end of the experiment, shifts toward amino acid utilization with BC additions in both crops potentially influenced crop growth and nitrogen‐use efficiency. In summary, BM+BC at 10 Mg·ha−1 performed best in this study during the first cropping season under cold and rainy conditions. Core Ideas: Biochar and biochar–manure additions increased wheat production.There were shifts toward amino acid utilization with biochar additions.Precipitation and temperature played an essential part in level of biochar addition benefits. [ABSTRACT FROM AUTHOR]

Greenhouse gases (GHG) emissions from agricultural practices contribute 14% of anthropogenic emissions to the atmosphere, and novel practices to reduce these emissions, including feeding cattle a modified diet, are of interest. This study examines how additions of manure from cattle fed a regular diet or a diet supplemented with 2% biochar, and biochar at 5 or 10 Mg ha−1, impact GHG emissions in a Gray Luvisol agricultural field experiment. Emissions of CH4 and N2O were monitored, and soil samples were collected to analyze exchangeable NPKS, microbial biomass, total C and N, electrical conductivity, and pH. Wheat (Triticum aestivum) was planted, and grain yield measured. We calculated the yield-based emission factor (EFyield) and cumulative area-based GHG emissions emission factor (EFarea). The results showed an up to 98.5% change in the inhibition of CH4 oxidation from biochar-manure + biochar at 5 and 10 Mg ha−1 compared to the CT. The biochar in biochar-manure may have acted as a biocide to methanotrophs, causing a reduction in the release of CH4 over time. Yet, there were no significant differences in N2O emissions amongst treatments. Therefore, biochar-manure + biochar at 5 and 10 Mg ha−1 applications may impact total GHG emissions and improve grain productivity and protein content compared to BM alone. [ABSTRACT FROM AUTHOR]

Improved N management is needed in intensive agriculture to mitigate nitrous oxide (N2O) emissions while sustaining high yields. We assessed the effectiveness of polymer‐coated urea (PCU); nitrification inhibitor 2,4‐dimethylpyrazol succinic acid (DMPSA), a biostimulant; and their combinations with granular urea and ammonium sulfate nitrate (ASN) fertilizers to reduce N2O emissions and to improve potato (Solanum tuberosum L.) productivity under irrigation. Sites were located in Lethbridge and Brooks, Alberta, Canada over two growing seasons. Tuber yield, grade, specific gravity, and N uptake were quantified. We used the chamber method to measure N2O fluxes from potato hills and furrows. The N2O emissions from furrow positions were at least two‐fold greater than those from hills at the Lethbridge site. Peak N2O emissions and increased N concentrations in potato petiole and soils occurred shortly after fertilizer applications. The overall average emission factor (EF) of N2O was 0.056% kg N2O–N kg−1 N fertilizer (accounting for emissions from unfertilized controls). Urea alone commonly exhibited the highest N2O fluxes. Admixing DMPSA with either urea or ASN lowered N2O emissions in only certain cases. For instance, in one growing season at the Brooks site, adding DMPSA to urea reduced the N2O emissions by 57%. Likewise, in one of the four site‐years in the study, 36% higher potato marketable yields were obtained when applying either ASN treated with DMPSA or PCU compared with the unfertilized controls (45 vs. 33 Mg ha−1). Results showed that under specific conditions, N application strategies using DMPSA admixed with either urea or ASN can maintain high potato yields while reducing N2O emissions relative to soils receiving these fertilizers without this additive. Core Ideas: Adding the inhibitor DMPSA to urea reduced N2O emissions in only one of four site‐years.Potato yield was increased 36% in one site‐year by the fertilizers ASN with DMPSA or PCU.Fertilizer options did not influence the overall nitrogen use efficiency or harvest indices.Nitrate concentrations in potato petioles were closely associated with availability of soil N.Nitrous oxide emissions from furrow positions were often greater than those from potato hills. [ABSTRACT FROM AUTHOR]