Effect of manure co-digestion on methane production, carbon retention, and fertilizer value of digestate.

Anaerobic digestion can provide benefits not only from the perspective of renewable energy production but also in the form of fertilization effect and increased retention of C in soils after digestate application. This study consisted of two phases, where the first phase assessed the suitability of carbon-rich co-feedstocks for methane production via laboratory testing. The second phase assessed the balance and stability of C before and after anaerobic digestion by systematic digestate characterization, and by evaluating its carbon retention potential using a modeling approach.

Methodological choices in size and density fractionation of soil carbon reserves - A case study on wood fiber sludge amended soils.

Soil organic carbon (SOC) is in the focus of research due to its central role in regulating climate and maintaining fertility and resilience of soils. Methodologically, shifting from whole soil C measurements to specific SOC fractions increases possibility to detect small changes in the vast SOC storage, and enhances estimation of SOC stability. However, SOC fractionation schemes are numerous and variable.

High organic carbon content constricts the potential for stable organic carbon accrual in mineral agricultural soils in Finland.

Sequestering carbon into agricultural soils is considered as a means of mitigating climate change. We used agronomic soil test results representing c. 95% of the farmed land area in Finland to estimate the potential of the uppermost 15 cm soil layer of mineral agricultural soils to sequester organic carbon (OC) and to contribute to the mitigation of climate change.

Industrial pilot scale slow pyrolysis reduces the content of organic contaminants in sewage sludge.

Pyrolysis has been gaining global interest as a viable option for reducing organic contaminant levels in waste materials such as sewage sludge (SS) for their subsequent use as a soil amendment. However, publicly available knowledge on the capacity of pyrolysis to reduce the levels in SSs is mostly based on laboratory or bench scale studies. The aim of this study was to examine the effects of industrial pilot scale slow pyrolysis at two temperatures and retention times (450 °C, 1 h and 500 °C, 1.

Pyroligneous Acids of Differently Pretreated Hybrid Aspen Biomass: Herbicide and Fungicide Performance.

The pyroligneous acids (PAs) of woody biomass produced by torrefaction have pesticidal properties. Thus, PAs are potential alternatives to synthetic plant protection chemicals. Although woody biomass is a renewable feedstock, its use must be efficient.

Slow pyrolysis liquid in reducing NH emissions from cattle slurry - Impacts on plant growth and soil organisms.

A substantial percentage of manure nitrogen (N) can be lost as gaseous ammonia (NH) during storage and field spreading. Lowering slurry pH is a simple and accepted method for preserving its N. Efficiency of slow pyrolysis liquid (PL) produced from birch (Betula sp.

Pulp and paper mill sludges decrease soil erodibility.

Declining carbon (C) content in agricultural soils threatens soil fertility and makes soil prone to erosion, which could be rectified with organic soil amendments. In a 4-yr field trial, we made a single application of three different organic sludges from the pulp and paper industry and studied their effects on cereal yield, soil C content, and fungal and bacterial composition. In laboratory rainfall simulations, we also studied the effects of the soil amendments on susceptibility to erosion and nutrient mobilization of a clay-textured soil by measuring the quality of percolation water passing through 40-cm intact soil monoliths during 2-d rainfall simulations over four consecutive years after application.

Are there environmental or agricultural benefits in using forest residue biochar in boreal agricultural clay soil?

Short-term agronomic and environmental benefits are fundamental factors in encouraging farmers to use biochar on a broad scale. The short-term impacts of forest residue biochar (BC) on the productivity and carbon (C) storage of arable boreal clay soil were studied in a field experiment. In addition, rain simulations and aggregate stability tests were carried out to investigate the potential of BC to reduce nutrient export to surface waters.

Cascade processing of softwood bark with hot water extraction, pyrolysis and anaerobic digestion.

A process model based on hot water extraction (HWE), slow pyrolysis and anaerobic digestion (AD) were used for pine and spruce bark utilisation. First tannins (32 mg/g and 11.8 mg/g, respectively) and polyphenols were recovered via HWE.

Quantitative characterization of pore structure of several biochars with 3D imaging.

Pore space characteristics of biochars may vary depending on the used raw material and processing technology. Pore structure has significant effects on the water retention properties of biochar amended soils. In this work, several biochars were characterized with three-dimensional imaging and image analysis.

A Simple Dynamic Model of Soil Test Phosphorus Responses to Phosphorus Balances.

Soil test P (STP) concentration indicates whether annual P applications can be expected to give yield increases and can also indicate an elevated risk of P mobilization and potential for P transfer to surface waters and groundwater from a particular field. Changes in STP with time thus project agronomic benefits and environmental risks of different P use strategies. To predict STP changes with time, we constructed a simple dynamic model for which the input variables are P balance and initial STP.

Conversion of dissolved phosphorus in runoff by ferric sulfate to a form less available to algae: Field performance and cost assessment.

Conversion of dissolved P by ferric sulfate into a particulate form sparingly available to algae was studied in 15 ditches in Finland using stand-alone dispensers for ferric sulfate administration. Ferric sulfate typically converted 60-70 % of dissolved P into iron-associated form, a process which required 250-650 kg per kg dissolved P. Mean cost was 160 EUR per kg P converted (range 20-400 EUR kg(-1)).

Effects of de-icing chemicals sodium chloride and potassium formate on cadmium solubility in a coarse mineral soil.

Excessive use of sodium chloride (NaCl) as de-icing chemical causes environmental problems, such as elevated chloride concentrations in groundwater. On vulnerable sites, this can be avoided by using alternative organic de-icing chemicals, such as potassium formate (KHCOO). The environmental impacts of KCHOO are, however, not well known.