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Schimmelpfennig S.,Institute for Experimental Plant Ecology | Muller C.,University College Dublin | Grunhage L.,Institute for Experimental Plant Ecology | Koch C.,Justus Liebig University | Kammann C.,Institute for Experimental Plant Ecology
Agriculture, Ecosystems and Environment | Year: 2014

Both reductions of greenhouse gas emissions and carbon sequestration have the potential to reduce global climate warming and avoid dangerous climate change. We assessed the sequestration potential as well as possible risks and benefits of carbon amendments (16 ± 4% of soil organic C) from Miscanthus × giganteus in different carbonization stages of a temperate grassland soil together with pig slurry: (1) untreated dried biomass (feedstock), (2) hydrothermally carbonized biomass (hydrochar) and (3) pyrolyzed biomass (biochar) in comparison to a control (only pig slurry application). The field study was complemented by a laboratory incubation study, followed by a growth experiment with Lolium perenne. In the field, greenhouse gas emissions (CO2, N2O, and CH4) were monitored weekly over 1.5 years and over three months in the lab. Initial nitrogen losses via ammonia emissions after substrate-slurry application were assessed in an additional greenhouse study. We found that biochar reduced soil and ecosystem respiration in incubation and in the field, respectively. Additionally, biochar improved methane oxidation, though restricted by emissions outbursts due to slurry amendment. It also reduced N2O emissions significantly in the lab study but not in the field. Hydrochar and feedstock proved to be easily degradable in incubation, but had no effect on ecosystem respiration in the field. Feedstock amendment significantly increased N2O emissions in incubation and one year after application likewise in the field. In a growth experiment subsequent to the incubation, only biochar amendment increased L. perenne biomass (+29%) significantly, likely due to N retention. In the field, biochar caused a significant shift in the plant species composition from grasses to forbs, whereas hydrochar significantly reduced yields within two growth periods (2011 and 2012). Ammonia emissions were significantly higher with feedstock and biochar compared to the control or acidic hydrochar. The overall results indicate that biochar is better suited for C sequestration and GHG mitigation in grasslands than hydrochar or the uncarbonized feedstock. However, NH3 emission reductions may only occur when the biochar is neutral or slightly acidic. © 2014 Elsevier B.V. All rights reserved. Source


Schimmelpfennig S.,Institute for Experimental Plant Ecology | Muller C.,Institute for Experimental Plant Ecology | Muller C.,University College Dublin | Grunhage L.,Institute for Experimental Plant Ecology | And 2 more authors.
Agriculture, Ecosystems and Environment | Year: 2014

Both reductions of greenhouse gas emissions and carbon sequestration have the potential to reduce global climate warming and avoid dangerous climate change. We assessed the sequestration potential as well as possible risks and benefits of carbon amendments (16. ±. 4% of soil organic C) from Miscanthus×giganteus in different carbonization stages of a temperate grassland soil together with pig slurry: (1) untreated dried biomass (feedstock), (2) hydrothermally carbonized biomass (hydrochar) and (3) pyrolyzed biomass (biochar) in comparison to a control (only pig slurry application).The field study was complemented by a laboratory incubation study, followed by a growth experiment with Lolium perenne. In the field, greenhouse gas emissions (CO2, N2O, and CH4) were monitored weekly over 1.5 years and over three months in the lab. Initial nitrogen losses via ammonia emissions after substrate-slurry application were assessed in an additional greenhouse study.We found that biochar reduced soil and ecosystem respiration in incubation and in the field, respectively. Additionally, biochar improved methane oxidation, though restricted by emissions outbursts due to slurry amendment. It also reduced N2O emissions significantly in the lab study but not in the field. Hydrochar and feedstock proved to be easily degradable in incubation, but had no effect on ecosystem respiration in the field. Feedstock amendment significantly increased N2O emissions in incubation and one year after application likewise in the field. In a growth experiment subsequent to the incubation, only biochar amendment increased L. perenne biomass (+29%) significantly, likely due to N retention. In the field, biochar caused a significant shift in the plant species composition from grasses to forbs, whereas hydrochar significantly reduced yields within two growth periods (2011 and 2012). Ammonia emissions were significantly higher with feedstock and biochar compared to the control or acidic hydrochar. The overall results indicate that biochar is better suited for C sequestration and GHG mitigation in grasslands than hydrochar or the uncarbonized feedstock. However, NH3 emission reductions may only occur when the biochar is neutral or slightly acidic. © 2014 Elsevier B.V. Source


Schimmelpfennig S.,Institute for Experimental Plant Ecology | Kammann C.,Institute for Experimental Plant Ecology | Moser G.,Institute for Experimental Plant Ecology | Grunhage L.,Institute for Experimental Plant Ecology | And 2 more authors.
Grass and Forage Science | Year: 2015

Biochar and hydrochar application to soil holds promise for climate change mitigation. This study provides first insights into the nutrient concentration and removal of grassland vegetation after addition of various carbon compounds together with pig slurry. Four treatments: control (no carbon application), feedstock, hydrochar and biochar from Miscanthus x giganteus were applied at a permanent grassland site near Giessen, Germany. Changes in plant functional groups, biomass production and nutrition status were monitored over 2 years. Total biomass production was not affected by the carbon amendments. However, biochar favoured growth of forbs over grasses, while legume growth was increased by all carbon amendments. The initial nutrient concentrations of the carbon compounds were enriched according to their degree of carbonization, potentially providing nutrients to plants. The plant biomass from hydro- and biochar amended plots, added up over 2 years, exhibited higher potassium concentrations compared to biomass from feedstock and control plots. All carbon amendments led to lower sodium concentrations in total biomass, compared to the control. Uncarbonized feedstock led to increased manganese concentrations in total biomass, while the concentrations of all other heavy metals were not influenced by any carbon amendment, compared to the control. From a plant and animal nutritional point of view, none of the carbon amendments reduced grassland yield or fodder quality. The study suggests that hydrochar and, even more so, biochar may provide a source of potassium to plants. © 2015 John Wiley & Sons Ltd. Source

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