Der organische Kohlenstoff im Boden (C_org) – Bedeutung, Bestimmung, Bewertung Soil organic carbon (C_org) – importance, determination, evaluation

Abstract

Organic carbon is a precondition for soil formation and for the preservation of its fertility. It has a crucial importance for yield formation and for the environment, in particular for the global carbon cycle. Precision and accuracy of its determination is difficult due to the variability and heterogeneity in soil. In long-term field experiments on sandy soils the differences in soil organic carbon (C org ) between treatments 'without fertilization' and 'optimally supplied' amount partly less than 0.2% C org . Moreover, even extreme changes in management cause annual changes of C org of only less than 0.01%. Due to the high spatial and temporal variability the standard error of C org is 40.1%. An evidence of the changes in soil C org due to management requires investigations in regular intervals (annual, as far as possible) over a longer period (420 years). At present, only the 'Humus Balance Method' (Humusbilanzmethode; VDLUFA 2004) is a reliable tool to estimate the organic matter supply in the field. Recommendations to conclude the organic matter supply level from difference of two C org measurements are wrong and misleading. A reduction of the atmospheric CO 2 -concentration by carbon accumulation in arable soils is not relevant. In sandy soils only about 10% of organic amendments are accumulated.

Contribution of organic amendments to soil organic matter detected by thermogravimetry

“…In literature the overall detection limit is described with standard errors of around 1 g C kg −1 soil ( Schumacher , ), whereas the analytical accuracy of this method is much better (0.1 g C kg −1 soil). Similar conclusions were reached by Körschens () and Gattinger et al () including the influence of soil sampling and other factors and implying higher analytical accuracy. As a result, monitoring small changes in SOC content due to management change, for example, is still a challenging task as the background SOC stock is large ( Jandl et al, ) and the level of SOC content remains difficult to assess ( Wessolek et al, ).…”

Soil organic carbon stock as an indicator for monitoring land and soil degradation in relation to United Nations' Sustainable Development Goals

“…Measurements of relevant parameters approximately every 10 years were recommended by Schrumpf, Schulze, Kaiser, and Schumacher () for a credible assessment of SOC stock dynamics. Ideally, those parameters should be determined every 20 years for a systematic proof of change in SOC stocks (Körschens, ). To facilitate effective policy developments, the accepted and precise methods have to be harmonized.…”

Biowaste Treatment – Recycling Potential for Humus Reproduction

“…Diese Aktivitäten können der Nährstoffwirkung oder der Bodenverbesserung zugeordnet werden, wobei letztere in der Bedeutung immer mehr dominiert, seit eine angemessene mineralische Düngung der Ackerböden gewährleistet ist [13]. Er fördert die Speicherung von Wasser und Nährstoffen, reguliert das Filter-und Puffervermögen, unterstützt die bodenbiologischen Prozesse und stabilisiert das Bodengefüge.…”

“…3 zeigt Humusgehalte, gemessen als organischer Kohlenstoff (C org ), für Böden mit unterschiedlichem Tongehalt, die in teils jahrzehntelangen Dauerversuchen untersucht wurden [13]. Die Ansicht, dass mehr Humus auch besseren Boden bedeutet, trifft nicht zu.…”

“…B. auf Sandböden nur etwa 10 % der zugeführten organischen Primärsubstanz im Boden akkumuliert, nach Erreichen des Fließgleichgewichtes praktisch nichts mehr angereichert [13]. einzustellen.…”