Phosphorus Behaviour and Its Basic Indices under Organic Matter Transformation in Variable Moisture Conditions: A Case Study of Fen Organic Soils in the Odra River Valley, Poland

Magdalena Debicka,Karolina Kowalczyk,Adam Bogacz

doi:10.3390/agronomy11101997

Magdalena Debicka, Karolina Kowalczyk + Show 1 more

Open Access

https://doi.org/10.3390/agronomy11101997

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Abstract

Lowering of groundwater levels caused by anthropogenic changes in the environment gives rise to global problems, most of which relate to soil degradation such as land desertification or organic soil degradation. The transformation of drainage-sensitive organic soils causes many irreversible changes during organic matter (OM) transformation. Phosphorous (P) behaviour is one of the aspects of OM transformation that requires further investigation, due to the P transformations’ complex dependency on many environmental factors. Our study aimed to characterise behaviour of P and find indices reflecting P changes under the influence of OM transformation in drained organic soils in the Odra river valley. The studies were carried out on soils representing different stages of soil degradation in which basic soil properties, including different P forms, were determined with commonly used methods. The results showed significantly higher content of soluble P forms (Pw, PCaCl2, PM3), particularly in the most drained postmurshic soil (P1). The indices used in this study—Ip, PSD, C:Pt, N:Pt—reflected well the P and OM transformations in organic soils degraded by drainage. This was indicated by numerous statistically significant relationships between the indices and basic soil properties (e.g., Ash, C, N), as well as different P forms (Pt, Pmin, Pox, Porg, Pw, PCaCl2, PM3). The PSD and Ip values increased and the C:Pt and N:Pt ratios decreased with the degree of OM mineralisation and the degree of site drainage (P3 < P2 < P1).

Highlights

Organic soils, in particular peat soils, are of unique importance in the natural environment
The results show that the Phosphorus Saturation Degree (PSD) of the studied soils increases according to the relationship P3 < Profiles 2 (P2) < Profile 1 (P1), i.e., an increase with the degree of land drainage
The results of our study on fen soils located in the Odra river valley showed changes in the chemical properties of organic soils degrading as a result of reduced moisture content

Summary

Introduction

In particular peat soils, are of unique importance in the natural environment These are classified as Histosols, namely, soils with at least 40 cm of organic material within the top 80 cm of the soil profile that are composed of at least 20–35% organic matter [1]. These soils cover almost 3% of the global land area [2,3,4] Their extent, is small considering these soils’ enormous importance to the environment on a global scale. Peatlands are a main store of water in local and global ecosystems, and, tend to have a regulating effect on the climate For these reasons, organic soils play a key role in counteracting climate change, which is one of the most significant problems currently facing human civilisation [5]

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