No abstract

Soil carbon sequestration arises from the interplay of carbon input and stabilization, which vary in space and time. Assessing the resulting microscale carbon distribution in an intact pore space, however, has so far eluded methodological accessibility. Here, we explore the role of soil moisture regimes in shaping microscale carbon gradients by a novel mapping protocol for particulate organic matter and carbon in the soil matrix based on a combination of Osmium staining, X-ray computed tomography, and machine learning. With three different soil types we show that the moisture regime governs C losses from particulate organic matter and the microscale carbon redistribution and stabilization patterns in the soil matrix. Carbon depletion around pores (aperture > 10 µm) occurs in a much larger soil volume (19–74%) than carbon enrichment around particulate organic matter (1%). Thus, interacting microscale processes shaped by the moisture regime are a decisive factor for overall soil carbon persistence.

Results of this study are highly relevant for all surgeons who perform percutaneous, minimally invasive hallux valgus surgery to avoid damage to the peripheral nerves. In addition, the data suggest an intensive training for surgeons before minimally invasive hallux valgus surgery is performed without supervision.

Abstract. Soil structure in terms of the spatial arrangement of pores and solid is highly relevant for most physical, biochemical processes in soil. While this is known for long a scientific approach to quantify soil structural characteristics was also missing for long. This was due to its buried nature but also due to the three-dimensional complexity. During the last two decades, tools to acquire full 3D images of undisturbed soil became more and more available and a number of powerful software tools were developed to reduce the complexity to a set of meaningful numbers. However, the standardization of soil structure analysis for a better comparability of the results is not well developed and the accessibility of required computing facilities and software is still limited. At this stage we introduce an open access Soil Structure Library (https://structurelib.ufz.de/) which offers well-defined soil structure analyses for X-ray CT data sets uploaded by interested scientists. At the same time, the aim of this library is to serve as an open data source for real pore structures as developed in a wide spectrum of different soil types under different site conditions all over the globe. By combining pore structure metrics with essential soil information requested during upload (e.g. bulk density, texture, organic carbon content\\ldots), this Soil Structure Library can be harnessed towards data mining and development of soil structure based pedotransfer functions. In this paper we describe the architecture of the Soil Structure Library and the provided metrics. This is complemented by an example how the data base can be used to address new research questions.