Effect of Peatland Siltation on Total and Labile C, N, P and K

Slawomir Smolczynski,Pawel Urbanowicz,Miroslaw Orzechowski,Barbara Kalisz

doi:10.3390/su13158240

Slawomir Smolczynski, Pawel Urbanowicz + Show 2 more

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https://doi.org/10.3390/su13158240

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Journal: Sustainability	Publication Date: Jul 23, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: University of Warmia and Mazury in Olsztyn

Abstract

Large areas of peatlands, in addition to the effect of drainage, were subjected to erosional process and were silted. The objective of the study was to verify whether siltation of peatlands hampers mineralization of remaining peat and alters labile C, N, P and K. Total C and N were measured on a CN analyzer, and total P and K on an ICP spectrometer after microwave digestion. The labile fractions of C, N, P and K were extracted with hot water and measured on the CN analyzer and ICP spectrometer. We noted that labile C, N, P and K concentrations in silted topsoil were lower than the values reported in unsilted topsoil. Higher concentration of labile compounds in peats is a signal of higher biological activity and mineralization of organic matter. A TOC/TP < 300 and TOC/TN of approximately 8 in topsoil suggested diminished mineralization and supported our hypothesis that siltation hampered mineralization of organic matter. The TOC/TK ratio proved to be a fine indicator of the state of organic soils siltation, which enabled the separation of unsilted peats from silted topsoil (on the base of value of 177). It can be assumed that the mineralization of peat layers is hampered by the above lying silted topsoil, which is less biologically active, having less oxygen, and therefore conserving underlying peats against oxidation.

Highlights

Soil organic matter (SOM) is a mixture of various organic compounds with a diversified susceptibility to decomposition and microbiological transformations
The topsoil murshes contained 40.5% of organic matter on average, with medium variability among the samples, while the colluvium contained the least amount of organic matter, less than 19%, with little variability among the analyzed samples (Table 1)
The total phosphorous (TP) content (0.15–1.32 g kg−1 ) was half of the average value obtained for colluvium or murshes, and TK content (0.21–1.06 g kg−1 ) was 10 times lower (Table 1, Table S1)

Summary

Introduction

Soil organic matter (SOM) is a mixture of various organic compounds with a diversified susceptibility to decomposition and microbiological transformations. For these reasons, the assessment of SOM quality requires the assessment of labile and/or stable organic matter pools [1,2]. The labile fraction is regarded as an indicator of soil productivity and quality and an important energy source for soil microorganisms [3,4,5]. It plays important role in soils, especially in the biogeochemistry of carbon, nitrogen and phosphorus [6]. The labile organic fraction constitutes a small proportion of SOM, it is one of the most mobile and bioavailable forms [8,12,13,14,15] and can indicate processes that control SOM accumulation and stabilization [16,17]

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