Linking biodiversity to biogeochemical cycling (C-N cycling) in grasslands by soil structure

Goals

Assessment of soil structure in differently managed grassland soils by X-ray computed tomography and micro tomography
Analysis of the relationship between soil structure and soil biota distributions
Prediction of C-N turnover in grassland soils by means of simulation models based on soil structure

Hypotheses

H1.     High biodiversity in grassland soils is connected with highly structured soil (macro pores, aggregates) and altered carbon and nitrogen turnover
H2.    The macro pore volume in grassland soils correlates positively with diversity and abundance of non-burrowing soil meso fauna.
H3.     The analysis of soil structure improves the understanding of turnover processes in soil.

Methods

Mechanical extraction of undisturbed soil samples (10 cm and 3 cm diameter) from all grassland EPs
Assessment of soil structure by X-ray computed tomography and micro tomography (resolution 0,25 mm bzw. 5-30 µm) of all grassland EPs
Morphometric analysis of soil structure at different scales

Cooperation with AG Schrumpf und Kandeler (Corg, microbial biomass) and AG Wolters (soil fauna)

Picture: The photo shows a meadow in the Schorfheide in April Two thousand eleven where sampling is being carried out. In the foreground, the grassy verge along an asphalted country road can be seen. Behind it, the meadow runs up a hill on the left where a herd of cattle is grazing. On the right of the meadow, there are people carrying out sampling work. Behind the meadow, unfoliaged bushes and trees can be seen, as well as further meadows and wooded hills on the horizon.

Spring sampling in the Schorfheide (April 2011)

Picture: The photo shows a metal device for taking undisturbed soil samples on a mown meadow. The lower part of the device consists of three struts which, viewed from above, form the shape of a ypsilon. Where the struts meet in the middle, a tripod column projects upwards. The motor-driven unit is attached to the stand in a height-adjustable manner. The cutting sleeve is attached to the unit for pre-cutting the sample and the piercing cylinder is attached to it in a fixed position for picking up the sample. Next to the device kneels an employee of the company renting the drill. The stainless steel cutting sleeve is on the floor in front of the man. In his left hand, the man holds a clear transparent piercing cylinder made of acrylic glass.

Device for taking undisturbed soil samples in grassland soil (spring 2011)

Picture: The photo shows a young female scientist kneeling in a sunlit mowed meadow with a soil sample in a clear transparent acrylic cylinder on the grass in front of her. The woman is using a knife to cut the surface of the soil sample to the size of the sample container.

Undisturbed soil sample in plastic cylinder

Picture: The photograph shows two men on a large mown meadow operating a device for taking undisturbed soil samples in rainy weather. One of the men is kneeling next to the device, the other is standing and pressing on the tripod column from above. To the right at the edge of the picture another person can be seen watching from behind. A row of unfoliaged trees can be seen on the horizon.

Soil sampling in the rain (spring 2011)

Publications

X-ray Computed Microtomography for the Study of the Soil–Root Relationship in Grassland Soils

Untersuchung der Bodenstruktur und der Wurzelentwicklung in unterschiedlich bewirtschafteten Grünlandstandorten mittels Röntgen-Computertomografie

Kuka K., Illerhaus B., Fox C. A., Joschko M. (2013): X-ray Computed Microtomography for the Study of the Soil–Root Relationship in Grassland Soils. Vadose Zone Journal 12 (4). doi: 10.2136/vzj2013.01.0014

A new method for the extraction of undisturbed soil samples for X-ray computed tomography

Maschinelle Entnahme ungestörter Bodenprobensäulen für die Röntgen-Computertomographie

Kuka K., Illerhaus B., Fritsch G., Joschko M., Rogasik H., Paschen H., Schulz H., Seyfarth M. (2013): A new method for the extraction of undisturbed soil samples for X-ray computed tomography. e-Journal of Nondestructive Testing 8, 1-8