Effect of sieving on ex-situ soil respiration of soils from three land use types

This study aims to investigate the effect of sieving on ex situ soil respiration (CO2 flux) measurements from different land use types. We collected soils (0–10 cm) from arable, grassland and woodland sites, allocated them to either sieved (4-mm mesh, freshly sieved) or intact core treatments and incubated them in gas-tight jars for 40 days at 10 °C. Headspace gas was collected on days 1, 3, 17, 24, 31 and 38 and CO2 analysed. Our results showed that sieving (4 mm) did not significantly influence soil respiration measurements, probably because micro aggregates (< 0.25 mm) remain intact after sieving. However, soils collected from grassland soil released more CO2 compared with those collected from woodland and arable soils, irrespective of sieving treatments. The higher CO2 from grassland soil compared with woodland and arable soils was attributed to the differences in the water holding capacity and the quantity and stoichiometry of the organic matter between the three soils. We conclude that soils sieved prior to ex situ respiration experiments provide realistic respiration measurements. This finding lends support to soil scientists planning a sampling strategy that better represents the inhomogeneity of field conditions by pooling, homogenising and sieving samples, without fear of obtaining unrepresentative CO2 flux measurements caused by the disruption of soil architecture

Leaf litter decomposition and nutrient release characteristics of several willow varieties within short-rotation coppice plantations in Saskatchewan, Canada

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 (kBiomass) and decomposition limit values (LVBiomass), along with associated release rates (kNutrient) and release limits (LVNutrient) 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 four-year rotation at four sites within Saskatchewan, Canada. The kBiomass, LVBiomass, kNutrient, and LVNutrient values varied among the willow varieties, sites, and nutrients, with average values of 1.7 year-1, 79 %, 0.9 year-1, and 83 %, respectively. Tissue N had the smallest kNutrient and LVNutrient values, while tissue K and Mg had the largest kNutrient and LVNutrient values, respectively. The leaf litter production varied among willow varieties and sites with an average biomass accumulation of 7.4 Mg ha-1 after the four-year rotation and associated C sequestration rate of 0.2 Mg C ha-1 yr-1. The average contribution of nutrients released from leaf litter decomposition during the four-year rotation to the plant available soil nutrient pool across varieties and sites was 22, 4, 47, 10, 112, and 18 kg ha-1 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

Biomass production and nutrient cycling in short-rotation coppice willow (Salix spp.) bioenergy plantations in Saskatchewan, Canada

Biomass energy is currently the largest renewable contributor to global energy supply and there is increasing demand for bioenergy feedstock. Consequently, the production of purpose-grown woody bioenergy crops, such as short rotation coppice (SRC) willow, is expected to proliferate. Although the economic and environmental benefits associated with SRC willow production are well documented, systematic assessments of nutrient cycling within these plantations are rare. The objective of this study was to examine biomass production and biogeochemical cycling of nitrogen (N), phosphorus (P), potassium (K), sulphur (S), calcium (Ca), and magnesium (Mg) during an initial four-year rotation of six willow varieties grown at four plantations along a 500 km north-south pedoclimatic gradient within Saskatchewan, Canada. Nutrient budgets were also calculated after quantifying various nutrient inputs (e.g., atmospheric deposition, soil mineral weathering, and organic matter mineralization), outputs (e.g., above- and below-ground biomass, leaching, and denitrification), and transfers (e.g., canopy exchange, leaf litter decomposition, and fine root turnover) affecting the plant available soil nutrient pool. Total stem, leaf litter, and below-ground (primarily fine roots) biomass production after four years averaged 19.0, 7.1, and 12.5 Mg ha-1, respectively, with corresponding soil nutrient budget deficits of 17, 39, 112, 271, and 74 kg ha-1 of N, P, K, Ca, and Mg, respectively, but a soil S surplus of 60 kg ha-1. Despite willow’s relatively low nutrient-demanding nature, negligible leaching and denitrification losses, and substantial nutrient cycling from leaf litter, the nutrient export in harvested biomass over multiple rotations will require soil nutrient amendments, particularly N and P, to maintain plantation productivity. Given the apparent eventual need for supplemental fertility to support adequate willow growth over the 22-yr plantation life span, the fate of broadcast 15N-labelled fertilizer was also examined. Though the willow accumulated less than ⅓ of the applied fertilizer N after one year, the majority of the residual fertilizer N (51%) remained available for willow uptake in subsequent years. Further research is needed to track the fate of applied fertilizers over multiple rotations to better understand fertilizer dynamics for optimizing SRC willow agronomy; thus helping to promote its viability as a biomass energy feedstock option

Amending soil with combinations of biochar and manure: impacts on soil properties, barley yield, and nutrient uptake

Non-Peer Reviewe

The residual effect of biochar and animal manure amendments on soil properties, canola yield, and fertilizer 15N recovery

Non-Peer Reviewe

Second-year decomposition and nutrient release characteristics of ten annual crop residues in south-central Saskatchewan, Canada

Non-Peer Reviewe

First rotation biomass production and nutrient cycling within short-rotation coppice willow plantations in Saskatchewan, Canada

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), sulphur (S), calcium (Ca), and magnesium (Mg) during the initial four-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-1, with calculated soil nutrient budget deficits (i.e., nutrient outputs > inputs + transfers) of 17, 39, 112, 271, and 74 kg ha-1 for N, P, K, Ca, and Mg, respectively, averaged across the varieties and sites, but a soil S surplus of 60 kg ha-1. 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

Yield response of IDC tolerant and susceptible soybean varieties to Fe fertilization in marginally Fe-deficient soils following simulated flooding

Non-Peer Reviewe

The response of wheat to rates, forms, and application method of copper fertilizer in a range of prairie soils

Non-Peer Reviewe

Impact of biochar and manure additions on canola growth and fate of applied nitrogen fertilizer in a Humic Vertisol and Brown Chernozem after four years

Non-Peer Reviewe