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Liquid hog manure (LHM) and solid cattle manure (SCM) are valuable soil amendments for the nutrients and organic matter they augment. However, desire to mitigate the N2O, CO2, and CH4 fluxes attendant with their use has led to the question of whether biochar co-applied with LHM and SCM could mitigate these greenhouse gas fluxes. A split-plot design was used at two agricultural field sites with contrasting soil types (Brown Chernozem and Black Vertisol) in Saskatchewan, Canada, to assess the effect of LHM and SCM (100 kg N ha−1), alone and in combination with two different biochars applied at 8 Mg C ha−1; produced using either slow or fast pyrolysis of willow (Salix spp.) feedstock. Intact cores were collected from the plots and the N2O, CO2, and CH4 fluxes were measured during a 6-week (42 days) lab incubation. The impact of manure amendment on greenhouse gas fluxes, was more apparent with LHM than SCM; reflecting higher inorganic N content, narrower C:N, and more easily mineralizable carbon in LHM. Co-applying biochar with the manure sources reduced the manure-related N2O emissions 31.5 to 43.1% and increased CH4 consumption 94.1% to 2.1 × compared with manure alone. Regardless of soil type, neither biochar co-applied with the manures affected the net CO2 fluxes compared with manure alone. The N2O emissions were principally influenced by the impact of biochar addition on NO3-N supply and pH, while the net CO2 fluxes were controlled by the opposing effects of heterotrophic (i.e., CO2 production) and postulated autotrophic (i.e., CO2 consumption) respiration. The CH4 consumption was related to the NH4-N supply and its influence on autotrophic methanotrophy. [ABSTRACT FROM AUTHOR]

Canola (Brassica napus) is the primary oilseed crop in western Canada; however, it is often grown on sulfur (S)-deficient soils. Moreover, canola has a high S demand compared to cereals and, therefore, is particularly sensitive to S deficiency. This study examined the growth and nutrient uptake responses of a high-yielding canola hybrid cultivar to S fertilization when grown on three contrasting soils differing in S fertility, with and without the addition of fertilizer S. The soils were collected from three soil-climatic zones within Saskatchewan (Brown, Black, and Gray) and three different fertilizer S forms were used: ammonium sulfate (AS); ammonium thiosulfate (ATS); and a composite fertilizer containing nitrogen (N), phosphorus (P), and S (NPS; 50-50 blend of sulfate (SO4) salt and elemental S). Sulfur fertilization increased the canola biomass, along with plant uptake of N, P, and S on all three soils. Fertilizer S use efficiency (i.e. recovery) ranged from 11-75%. For all three soils, the general trend among fertilizer S forms for biomass, nutrient uptake, and fertilizer use efficiency was AS > ATS > NPS. The greatest differences were observed with the Gray soil, which had the poorest S fertility. Residual soil SO4 after harvest was greater for ATS and NPS; reflecting continued oxidation of thiosulfate and elemental S to SO4. Principal component analysis demonstrated the importance of tissue N:S ratio as a key diagnostic measurement related to canola growth and nutrient uptake in S-deficient soils. [ABSTRACT FROM AUTHOR]

The potential of biochar to improve numerous soil physical, chemical and biological properties is well known. However, previous research has concentrated on old and highly weathered tropical soils with poor fertility, while reports regarding the influence of biochar application on relatively young and fertile temperate prairie soils are limited. Furthermore, the mechanism(s) underlying biochar-induced effects on the plant availability of inorganic nitrogen (N) fertilizers and their relationship to greenhouse gas production is not well understood. The objective of this study was to determine the effect of a biochar soil amendment, produced by slow pyrolysis using shrub willow ( Salix spp.) bioenergy feedstock, on CO, NO and CH fluxes by two contrasting marginal soils from Saskatchewan, Canada with and without added urea, over a 6-week incubation period. Biochar decreased soil N availability after 6 weeks only in the lower organic matter (Brown) soil, with no effect on the Black soil, regardless of fertilizer N addition, which was attributed to soil N immobilization by heterotrophs mineralizing the labile biochar-carbon. There appeared to be a synergistic effect when combining biochar and urea, evidenced by enhanced urease activity and higher initial nitrification rates compared to biochar or fertilization alone. The accelerated urea hydrolysis in the presence of biochar may increase NH volatilization losses associated with urea fertilization and, therefore, warrants further investigation. The decreased NO emissions following biochar addition, with (both soils) or without (Black soil) fertilizer N, could be due to decreased ammonium and nitrate availability, along with changes in denitrification potential as related to improved aeration. Biochar significantly reduced the water-filled pore space, which concurrently increased CH consumption in both soils. The lack of biochar effect on CO emissions from either soil, with or without fertilizer N, suggests enhanced CO consumption by autotrophic nitrifiers. Biochar application appears to be an effective management approach for improving NO and CH fluxes in temperate prairie soils. [ABSTRACT FROM AUTHOR]

Although numerous studies have quantified different social, economic, energetic, and environmental benefits associated with short-rotation coppice (SRC) willow plantations, comprehensive assessments of nutrient cycling are rare. The objective of this study was to examine the biomass production and attendant biogeochemical cycling of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), and magnesium (Mg) during the initial 4-year rotation of six willow varieties grown at four locations along a 500 km north-south pedoclimatic gradient within Saskatchewan, Canada. Nutrient budgets consisted of quantifying various nutrient inputs (e.g., atmospheric deposition and soil mineral weathering), outputs (e.g., fine and coarse root biomass, leaf biomass, harvested biomass, leaching, and denitrification), and transfers (e.g., soil organic matter mineralization, canopy exchange, leaf litter decomposition, and fine root turnover) associated with the plant available soil nutrient pool. Total above- and below-ground production during the rotation was approximately 40 Mg ha, with calculated soil nutrient budget deficits (i.e., nutrient outputs > inputs + transfers) of 17, 39, 112, 271, and 74 kg ha for N, P, K, Ca, and Mg, respectively, averaged across the varieties and sites, but a soil S surplus of 60 kg ha. While soil nutrient budget deficits varied among sites, there were no significant differences ( P > 0.05) among willow varieties. Despite the relatively low nutrient-demanding nature of willow and negligible leaching or denitrification losses, nutrient export in harvested biomass over multiple rotations will require soil nutrient amendments to maintain SRC willow productivity, particularly N and P, albeit a fraction of the amount required for annual agronomic crops. [ABSTRACT FROM AUTHOR]

Quantifying short-rotation coppice (SRC) willow leaf litter dynamics will improve our understanding of carbon (C) sequestration and nutrient cycling potentials within these biomass energy plantations and provide valuable data for model validation. The objective of this study was to quantify the decomposition rate constants ( k) and decomposition limit values (LV), along with associated release rates ( k) and release limits (LV) of nitrogen (N), phosphorus (P), potassium (K), sulphur (S), calcium (Ca), and magnesium (Mg) of leaf litter from several native and exotic willow varieties during an initial 4-year rotation at four sites within Saskatchewan, Canada. The k, LV, k, and LV values varied among the willow varieties, sites, and nutrients, with average values of 1.7 year, 79 %, 0.9 year, and 83 %, respectively. Tissue N had the smallest k and LV values, whereas tissue K and Mg had the largest k and LV values, respectively. The leaf litter production varied among willow varieties and sites with an average biomass accumulation of 7.4 Mg ha after the 4-year rotation and associated C sequestration rate of 0.2 Mg C ha year. The average contribution of nutrients released from leaf litter decomposition during the 4-year rotation to the plant available soil nutrient pool across varieties and sites was 22, 4, 47, 10, 112, and 18 kg ha of N, P, K, S, Ca, and Mg, respectively. Principal component analysis identified numerous key relationships between the measured soil, plant tissue, climate, and microclimate variables and observed willow leaf litter decomposition and nutrient-release characteristics. Our findings support the contention that SRC willow leaf litter is capable of enhancing both soil organic C levels and supplementing soil nutrient availability over time. [ABSTRACT FROM AUTHOR]

Routine monitoring of above ground biomass within purpose-grown willow biomass energy production systems is important for timing harvest and other operations to maximize profit and increase plantation productivity. The objective of this study was to assess the efficacy of an elegant nondestructive mensurative technique for providing reliable estimates of harvestable biomass for six willow varieties during a 3-year rotation. The LAI-2000 Plant Canopy Analyser was used to measure the stem area index of growing willow and relate it to harvestable biomass at four locations within Saskatchewan, Canada over a 3-year period. Given the highly significant relationship ( R = 0.95; P < 0.0001) between measured stem area index and harvestable willow biomass, independent of variety, age, or location, this simple mensurative technique is a promising alternative for estimating above ground biomass in short-rotation willow plantations. [ABSTRACT FROM AUTHOR]