The Responsiveness of Permanganate Oxidizable Carbon to Different Management Practices in Coarse-Textured Soils of Florida
Abstract
Permanganate oxidizable carbon (POXC) has emerged as a commonly used indicator to measure soil C cycling and soil health. However, the responsiveness of POXC to different management practices, and its usefulness to understand C cycling and determine whether a soil is healthy or not, remain unclear. This is especially true in soils that differ from the main areas of the US where POXC has been promoted as a key soil health indicator, such as Florida that is dominated by very coarse-textured soils and subject to a subtropical climate. In order to better understand how POXC responds to different management practices, weve compared the response of POXC to management in three different experiments. We found that POXC was indeed responsive to different management practices among agroecosystems, as it increased 1) after eight weeks of cover cropping (with no difference among species or mixtures) in vegetable systems; 2) after roughly two decades of incorporating a perennial grass into a conventional peanut-cotton rotation; and 3) after the input of different manures and composts in an eight-week incubation study. Organic amendments had a much more pronounced effect on POXC than cover cropping or the inclusion of perennial grasses, although changes in POXC did not necessarily reflect changes in total C, at least in the short term. POXC exhibited intra-annual variability in many studies, highlighting both its potential as a soil C pool that responds rapidly to management and the importance of standardizing sampling protocols. Finally, POXC was often variable, which was likely driven by the coarse texture of the soils used in these studies, which made it easier to detect a signal from a given management practice but also increased the difficulty in determining concentrations accurately. Overall, our results indicate that POXC could be used as a management-responsive soil C pool in Florida agroecosystems, although its use will need to be further refined in these coarse-textured soils.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B15M1583M