Search

Boreal lands have long been considered unsuitable for agriculture. Climate change projections support a shift towards increased agricultural production in boreal ecosystems via land use conversion. Depending on the conversion protocol, the new plough layer may variably reflect the properties of different soil depths. This study assessed how adding mineral or organic fertilizer sources to distinct soil layers within ploughing depth (0–15 cm [topsoil] or 15–30 cm [subsoil]) affects nutrient uptake and crop productivity. Locally relevant organic waste fertilizers (dairy manure [DMN], recirculating aquaculture system supernatant [SUP] and slurry [RAS]), were compared against mineral fertilizer. Tall fescue was used to verify agronomic responses. Starting available nutrient concentrations were balanced as necessary with mineral N and P fertilizers. Except for NH4‐nitrogen, both soils were of apparent similar fertility (total C < 1%); unfertilized, neither could support significant plant growth. Subsoil‐based growth was fast but limited in time reflecting immediately available nutrients. Topsoil led to delayed, extended growth. This might be due to dichotomous priming effects: during the duration of the experiment up to 36% of subsoil carbon was lost, while the topsoil gained up to 49% carbon, most apparent for DMN. While RAS led to the greatest N and P acquisition efficiencies for topsoil, it had no such effect for subsoil, suggesting distinct fixation and mineralization processes. Dissimilar C cycling and nutrient acquisition for the two soil depths indicates that site‐specific considerations that include soil health parameters with commonly tested available nutrients are needed where podzols are farmed after land‐use conversion. [ABSTRACT FROM AUTHOR]

Despite the agricultural expansion into Canada's boreal ecoregion, little is known about the phosphorus (P) adsorption capacity in natural and managed Podzols' soil profiles. This information is critical for informing management decisions for P use efficiency and mitigating related environmental risks. Thus, this study aimed to evaluate P adsorption characteristics of podzolic horizons in natural and managed soil using nonlinear Langmuir and Freundlich adsorption models. A batch adsorption experiment was conducted using soils collected from distinct horizons of forested and managed fields in eastern and central Newfoundland, Canada. Nonlinear Langmuir and Freundlich fitted models had r values >.99 regardless of horizons, locations, and management history. The organic LFH, a surface horizon typical for forested Podzols, and a long‐term managed Ap horizon had the highest P retention capacities when compared to either newly converted soils or soils used as tree nursery following conversion from natural forest. A significant linear correlation and multiple regression models (p <.05) were established between P adsorption parameters and selected soil properties. Results suggest that following conversion from forest to agricultural use, long‐term management that includes tillage and lime and fertilizer application creates an Ap horizon with strong adsorption capacity, which could still fix P and serve as a source of P. The newly converted soils and the deeper soil horizons, for both natural and converted lands, do act mainly as P sinks; hence, crops may need larger quantities of P fertilizer increasing fertilizer expenses and also increasing future legacy P. [ABSTRACT FROM AUTHOR]

Numerous studies conducted so far have shown that biochar has a significant effect on physical, chemical and biological properties of soils. Biochar can be used to alleviate the effects of soil contamination with organic and inorganic compounds, for instance, to reduce the mobility of heavy metals. The aim of the research was to evaluate the effect of pig manure and poultry litter, as well as biochars produced from these materials at a temperature of 300 °C on Cu, Cd, Pb and Zn contents in mobile and organic matter-bound forms in soil. The research was conducted under laboratory conditions. The materials were introduced into sandy acid soil in doses of 0.5, 1.0 and 2.0% w/w. The application of pig manure-derived biochar ( BPM) and poultry litter-derived biochar ( BPL), depending on the amount added, reduced the mobility of copper from 28 to 69%, from 77 to 100% in the case of cadmium, from 94 to 99% in the case of lead, and from 15 to 97% in the case of zinc. The 2% amendment of pig manure ( PM) and poultry litter ( PL) caused an increase in the content of Cu extracted with NH4 NO3 in comparison with the control treatment. A similar situation was observed in the case of zinc after the application of 0.5 and 1% amendments of pig manure ( PM). Cu, Cd, Pb and Zn contents extracted with 0.025 mol C10H22N4O8 were higher than contents of these elements extracted with 1 m NH4 NO3, mainly due to different extraction force of the extractants. The obtained results indicate that, compared with the content determined in soil from the control treatment, 1 and 2% amendments of both unconverted and thermally converted materials to the soil had a greater effect on contents of Cu, Pb and Zn in the organic matter-bound fraction than the 0.5% amendment. The organic materials applied did not affect the content of cadmium in organic matter-bound fraction. [ABSTRACT FROM AUTHOR]

In temperate climates with surplus precipitation and low temperatures during autumn and winter, nitrate catch crops have become crucial in reducing nitrate leaching losses. Preferably, the N retained by the catch crop should remain in the soil and become available to the next main crop. Fodder radish ( Raphanus sativus, L.) has emerged as a promising nitrate catch crop in cereal cropping, although the course of remineralization of residue N following termination of this frost-sensitive crucifer remains obscured. We incubated radish residues of different age (different planting and harvest dates) with a loamy sand soil; mineralization of residue N was determined after 1, 2, 4 and 7 months of incubation at 2 °C and 10 °C. Incubations with soil only and with residues of white mustard ( Sinapis alba, L) and perennial ryegrass ( Lolium perenne, L.) were included as references. Using linear regression, net N release was fitted to plant chemical characteristics (initial concentrations of N, fibre fractions, lignin and C/N ratio). Residue C/N ratio (ranging from 10 to 25) and N concentration (ranging from 17 to 40 mg N/g dry matter) showed superior fits to net N release at both temperatures ( r2, 0.64-0.94) while fibre analyses provided inferior fits ( r2, 0.12-0.64). This was true across planting date and plant age. Net N release after 7 months of incubation at 2 °C and 10 °C accounted for up to 40% and 50% of residue N, respectively. During most of the incubation period, nitrate dominated the mineral N pool at both temperatures. The N mineralization and nitrification potential at these low soil temperatures suggest that a considerable fraction of the N captured by nitrate catch crops may be remineralized, nitrified and thus available for plant uptake but also for loss by leaching and denitrification. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to examine the utility of applying a microarray that incorporates virulence genes with heavy metal resistance and antibiotic genes to depict distinct water samples from agricultural watershed creek in Eastern Ontario. The study used the fixed assets management system (FAMD) software to measure uncertainties in the signal data. Analysis of multilocus fingerprinting data sets with missing data has revealed that any variability in microarray signals had a marginal impact on data interpretation.

We evaluated the impact of the manure type used in soil-manure mixtures on the detection of culturable E. coli as tested in water quality monitoring. A series of incubation experiments, lasting up to 200 d, allowed evaluation of the potential impact of manure X soil interactions on the augmentation of culturable E. coli. Two soil types (sandy loam and a silt loam), two manure types (liquid swine manure and solid beef cattle manure), and three temperature levels (4, 12, and 20°C) were investigated. The significance of the presence of competing microorganisms was estimated by comparing results from manure mixtures with sterile and nonsterile soils. Water content in the soil-manure mixtures was maintained close to field capacity to eliminate the specific impact of water availability. We found that culturability of the indicator organism, E. coli, changed with time and was dependent on the type of manure used and its interaction with soil. Escherichia coli could be cultured for a longer time from soils with liquid manure additions. Whereas E. coli numbers were initially higher from soils treated with solid beef cattle manure, their numbers decreased more rapidly and the duration of their apparent survival was shorter. Resilience of culturable E. coli was independent of their initial numbers in manure. [ABSTRACT FROM AUTHOR]