The effect of a single cut (simulated grazing) and regrowth of Lolium perenne on CO2 efflux from ... more The effect of a single cut (simulated grazing) and regrowth of Lolium perenne on CO2 efflux from soil (loamy Haplic Luvisol), on below-ground C translocation and on the distribution of plant C among different soil particle size fractions was investigated under controlled conditions with and without N fertilization by pulse labelling with 14C 7 times (four before and three after the cutting). The amount of 14C respired from the rhizosphere of Lolium decreased by a factor of about 3 during 1 month of growth. At the same time the amount of 14C stored in soil increased. Cut and non-fertilized plants respired less C in the rhizosphere compared to the uncut plants and cut fertilized plants. About 80% of the root-derived CO2 efflux originated from the C assimilated after defoliation, and 20% originated from the C assimilated before cutting. N fertilization decreased the below-ground C losses (root respiration and exudation) during regrowth. The shoot is the main sink of assimilated C before and after the defoliation. N fertilization led to higher C incorporation into the shoot parts growing after defoliation compared to unfertilized plants. A lower incorporation of 14C was observed in the roots of N fertilized plants. The relative growth rates (expressed as 14C specific activity) of roots and stubble were minimal and that of shoot parts growing after defoliation was maximal. Twelve percent of 14C was found in the newly grown leaves after regrowth; nevertheless, 4.7% and 2.4% of 14C in the new shoot parts were translocated from the root and shoot reserves of unfertilized and fertilized plants, respectively. Most of the C retranslocated into the new Lolium leaves originates from the stubble and not from the roots. Between 0.5% and 1.7% of 14C recovered in shoots and below-ground C pools was found in the soil microbial biomass. Cutting and fertilization did not change 14C incorporation into the microbial biomass and did not affect xylanase, invertase, and protease activities. Tracing the assimilated C in particle size fractions revealed maximal incorporation for the sand and clay fraction.
ABSTRACT Modifications in temperature and precipitation due to climate change will likely affect ... more ABSTRACT Modifications in temperature and precipitation due to climate change will likely affect carbon cycling and soil respiration in terrestrial ecosystems. Despite the important feedback mechanism of ecosystems to climate change, there is still a lack of experimental observation in agricultural ecosystems. In July 2008, we established the Hohenheim Climate Change (HoCC) experiment to investigate effects of elevated temperature and altered precipitation on soil respiration in an arable soil (mean annual temperature and precipitation 8.7 °C and 679 mm, respectively). We elevated soil temperature to 4 cm depth by 2.5 °C, reduced the amount of summer precipitation by 25%, and extended dry intervals between precipitation events. For two years, CO2 fluxes were measured weekly and aboveground plant biomass and soil microbial biomass was determined. The results of the two-year study underline the importance of soil moisture as a driving factor in ecosystem response to climate change. Soil warming did not increase soil respiration in the first year; in the second year, a 27% increase was measured. The differential response of soil respiration to warming was most likely driven by soil moisture. In summer 2009, water limitation reduced microbial biomass in the heated plots thereby suppressing the stimulatory effect of elevated temperature on soil microorganisms. In summer 2010, the reduction in soil moisture was less pronounced and microbial biomass and respiration were not affected by water limitation. Temperature elevation significantly reduced Q10 values of soil respiration by 0.7–0.8. Altered precipitation showed only minor effects during the first two years of the experiment. We conclude from our study that the moisture regime of soils under elevation of temperature will largely determine whether different soils will serve either as carbon sources or as carbon sinks.
ABSTRACT According to the method for estimating soil aggregate stability (SAS) described by Kempe... more ABSTRACT According to the method for estimating soil aggregate stability (SAS) described by Kemper and Koch, a new sieving device has been constructed to improve manipulation and the rapidity of the analysis. The method of determination is described. Multiple replications of several samples that have been carried out by the members of the Austrian Soil Physics Research Group, showed a small standard deviation on the same soil samples. Storage of soil samples before measuring may cause a variation (increase) in SAS. The spatial variability of SAS on three field plots turned out to be relatively low. However, statistically significant differences were obtained, which proofs the high precision of the modified machine. Furthermore a significant influence of cattle slurry treatments on SAS of permanent grassland soil could be detected.
The lipid composition of Collembola and their potential food resources was assessed in three deci... more The lipid composition of Collembola and their potential food resources was assessed in three deciduous forest stands, in order to gain insight into food web linkages under field conditions. Fatty acids (FAs) previously assigned as trophic markers in laboratory experiments were used to investigate feeding strategies in situ. As potential food sources soil microbiota and plant debris were characterised by
Earthworms are key agents in organic matter decomposition, as they remove surface plant litter ma... more Earthworms are key agents in organic matter decomposition, as they remove surface plant litter material and mix it with mineral soil. Plant litter material is comminuted in the gizzard of anecic earthworms and this is enhanced if sand particles are available. We hypothesize that this comminution of soil and litter will result in changes in the distribution of soil organic
Die Bodengenetik ist die Lehre von der Entwicklung der Böden. Ein Boden ist ein Naturkörper, der ... more Die Bodengenetik ist die Lehre von der Entwicklung der Böden. Ein Boden ist ein Naturkörper, der an der Erdoberfläche unter einem bestimmten Klima, einer bestimmten streuliefernden Vegetation und Population von Bodenorganismen durch bodenbildende Prozesse (Verwitterung und Mineralbildung, Zersetzung und Humifizierung, Gefügebildung und verschiedene Stoffumlagerungen) aus einem Gestein entsteht.
Alle Böden unserer Erde sind nützlich. Sie dienen dem Naturhaushalt, der Pflanzen- und Tierproduk... more Alle Böden unserer Erde sind nützlich. Sie dienen dem Naturhaushalt, der Pflanzen- und Tierproduktion oder vielfältigen Zwecken der Zivilisation (vgl. Kap. 1.2). Je größer die Bevölkerung unserer Erde wird, desto mehr konkurrieren verschiedene Nutzungen um ein und denselben Boden. Deshalb wird häufiger die Grundfrage gestellt: Ist dieser Boden für eine bestimmte Nutzung geeignet? Diese Frage ist so alt wie der
Böden sind Naturkörper und als solche vierdimensionale Ausschnitte aus der Erdkruste, in denen si... more Böden sind Naturkörper und als solche vierdimensionale Ausschnitte aus der Erdkruste, in denen sich Gestein, Wasser, Luft und Lebewelt durchdringen. Wichtig ist dabei, dass die Böden belebt sind. Sie dürfen nicht als Lebewesen, sondern müssen als ein komplexes Poren- und Festkörpersystem betrachtet werden. Böden bestehen dabei aus vier Phasen, aus der gasförmigen, der flüssigen, der festen mineralischen und der festen
Böden sind Naturkörper und als solche durch jeweils typische physikalische Eigenschaften gekennze... more Böden sind Naturkörper und als solche durch jeweils typische physikalische Eigenschaften gekennzeichnet; Farbe (Kap. 6.8) und Körnung (Kap. 6.1) fallen am meisten ins Auge. Sie sind daher wichtige Bestandteile einer jeden Bodenbeschreibung.
The effect of a single cut (simulated grazing) and regrowth of Lolium perenne on CO2 efflux from ... more The effect of a single cut (simulated grazing) and regrowth of Lolium perenne on CO2 efflux from soil (loamy Haplic Luvisol), on below-ground C translocation and on the distribution of plant C among different soil particle size fractions was investigated under controlled conditions with and without N fertilization by pulse labelling with 14C 7 times (four before and three after the cutting). The amount of 14C respired from the rhizosphere of Lolium decreased by a factor of about 3 during 1 month of growth. At the same time the amount of 14C stored in soil increased. Cut and non-fertilized plants respired less C in the rhizosphere compared to the uncut plants and cut fertilized plants. About 80% of the root-derived CO2 efflux originated from the C assimilated after defoliation, and 20% originated from the C assimilated before cutting. N fertilization decreased the below-ground C losses (root respiration and exudation) during regrowth. The shoot is the main sink of assimilated C before and after the defoliation. N fertilization led to higher C incorporation into the shoot parts growing after defoliation compared to unfertilized plants. A lower incorporation of 14C was observed in the roots of N fertilized plants. The relative growth rates (expressed as 14C specific activity) of roots and stubble were minimal and that of shoot parts growing after defoliation was maximal. Twelve percent of 14C was found in the newly grown leaves after regrowth; nevertheless, 4.7% and 2.4% of 14C in the new shoot parts were translocated from the root and shoot reserves of unfertilized and fertilized plants, respectively. Most of the C retranslocated into the new Lolium leaves originates from the stubble and not from the roots. Between 0.5% and 1.7% of 14C recovered in shoots and below-ground C pools was found in the soil microbial biomass. Cutting and fertilization did not change 14C incorporation into the microbial biomass and did not affect xylanase, invertase, and protease activities. Tracing the assimilated C in particle size fractions revealed maximal incorporation for the sand and clay fraction.
ABSTRACT Modifications in temperature and precipitation due to climate change will likely affect ... more ABSTRACT Modifications in temperature and precipitation due to climate change will likely affect carbon cycling and soil respiration in terrestrial ecosystems. Despite the important feedback mechanism of ecosystems to climate change, there is still a lack of experimental observation in agricultural ecosystems. In July 2008, we established the Hohenheim Climate Change (HoCC) experiment to investigate effects of elevated temperature and altered precipitation on soil respiration in an arable soil (mean annual temperature and precipitation 8.7 °C and 679 mm, respectively). We elevated soil temperature to 4 cm depth by 2.5 °C, reduced the amount of summer precipitation by 25%, and extended dry intervals between precipitation events. For two years, CO2 fluxes were measured weekly and aboveground plant biomass and soil microbial biomass was determined. The results of the two-year study underline the importance of soil moisture as a driving factor in ecosystem response to climate change. Soil warming did not increase soil respiration in the first year; in the second year, a 27% increase was measured. The differential response of soil respiration to warming was most likely driven by soil moisture. In summer 2009, water limitation reduced microbial biomass in the heated plots thereby suppressing the stimulatory effect of elevated temperature on soil microorganisms. In summer 2010, the reduction in soil moisture was less pronounced and microbial biomass and respiration were not affected by water limitation. Temperature elevation significantly reduced Q10 values of soil respiration by 0.7–0.8. Altered precipitation showed only minor effects during the first two years of the experiment. We conclude from our study that the moisture regime of soils under elevation of temperature will largely determine whether different soils will serve either as carbon sources or as carbon sinks.
ABSTRACT According to the method for estimating soil aggregate stability (SAS) described by Kempe... more ABSTRACT According to the method for estimating soil aggregate stability (SAS) described by Kemper and Koch, a new sieving device has been constructed to improve manipulation and the rapidity of the analysis. The method of determination is described. Multiple replications of several samples that have been carried out by the members of the Austrian Soil Physics Research Group, showed a small standard deviation on the same soil samples. Storage of soil samples before measuring may cause a variation (increase) in SAS. The spatial variability of SAS on three field plots turned out to be relatively low. However, statistically significant differences were obtained, which proofs the high precision of the modified machine. Furthermore a significant influence of cattle slurry treatments on SAS of permanent grassland soil could be detected.
The lipid composition of Collembola and their potential food resources was assessed in three deci... more The lipid composition of Collembola and their potential food resources was assessed in three deciduous forest stands, in order to gain insight into food web linkages under field conditions. Fatty acids (FAs) previously assigned as trophic markers in laboratory experiments were used to investigate feeding strategies in situ. As potential food sources soil microbiota and plant debris were characterised by
Earthworms are key agents in organic matter decomposition, as they remove surface plant litter ma... more Earthworms are key agents in organic matter decomposition, as they remove surface plant litter material and mix it with mineral soil. Plant litter material is comminuted in the gizzard of anecic earthworms and this is enhanced if sand particles are available. We hypothesize that this comminution of soil and litter will result in changes in the distribution of soil organic
Die Bodengenetik ist die Lehre von der Entwicklung der Böden. Ein Boden ist ein Naturkörper, der ... more Die Bodengenetik ist die Lehre von der Entwicklung der Böden. Ein Boden ist ein Naturkörper, der an der Erdoberfläche unter einem bestimmten Klima, einer bestimmten streuliefernden Vegetation und Population von Bodenorganismen durch bodenbildende Prozesse (Verwitterung und Mineralbildung, Zersetzung und Humifizierung, Gefügebildung und verschiedene Stoffumlagerungen) aus einem Gestein entsteht.
Alle Böden unserer Erde sind nützlich. Sie dienen dem Naturhaushalt, der Pflanzen- und Tierproduk... more Alle Böden unserer Erde sind nützlich. Sie dienen dem Naturhaushalt, der Pflanzen- und Tierproduktion oder vielfältigen Zwecken der Zivilisation (vgl. Kap. 1.2). Je größer die Bevölkerung unserer Erde wird, desto mehr konkurrieren verschiedene Nutzungen um ein und denselben Boden. Deshalb wird häufiger die Grundfrage gestellt: Ist dieser Boden für eine bestimmte Nutzung geeignet? Diese Frage ist so alt wie der
Böden sind Naturkörper und als solche vierdimensionale Ausschnitte aus der Erdkruste, in denen si... more Böden sind Naturkörper und als solche vierdimensionale Ausschnitte aus der Erdkruste, in denen sich Gestein, Wasser, Luft und Lebewelt durchdringen. Wichtig ist dabei, dass die Böden belebt sind. Sie dürfen nicht als Lebewesen, sondern müssen als ein komplexes Poren- und Festkörpersystem betrachtet werden. Böden bestehen dabei aus vier Phasen, aus der gasförmigen, der flüssigen, der festen mineralischen und der festen
Böden sind Naturkörper und als solche durch jeweils typische physikalische Eigenschaften gekennze... more Böden sind Naturkörper und als solche durch jeweils typische physikalische Eigenschaften gekennzeichnet; Farbe (Kap. 6.8) und Körnung (Kap. 6.1) fallen am meisten ins Auge. Sie sind daher wichtige Bestandteile einer jeden Bodenbeschreibung.
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Papers by Ellen Kandeler