Fractionation of Soil Organic Matter into Labile and Stable Fractions

Marek Kopecký,Ladislav Menšík,Kristýna Perná,Miroslav Dumbrovský,Ladislav Kolář,Mohammad Ghorbani,Yves Theoneste Murindangabo,Petr Konvalina,Radka Váchalová,Petr Mráz

doi:10.3390/agronomy12010073

Abstract

The present study aims to test and evaluate the efficiency of a new modified method of organic matter evaluation. It allows the assessment of the quality and quantity of the primary soil organic matter and the stable organic fractions separately. The new method was tested in six soil samples of different localities in the Czech Republic. This method is based on observing reaction kinetics during the oxidation of soil organic matter and measuring the cation-exchange capacity of stable organic fractions. The results were compared with classical methods, which rely on the isolation of humic substances, determination of the content of humic acids and fulvic acids and their ratio CHA:CFA, quotient E4/6, and fractionation of soil organic matter according to resistance to oxidation. It turned out that the results of the new modified method are more sensitive in comparison with the results obtained by classical procedures. The linear regression demonstrated the dependence between the amounts of soil organic matter determined by the classical method compared with the modified method. Moreover, the new modified method was found to be faster and not demanding on laboratory equipment. The new method has been improved to be easily repeatable, and some shortcomings of the previous method were eliminated. Based on our results and other recent studies, the modified method may be recommended for the practical evaluation of soil organic matter conditions.

Highlights

Soil terrestrial ecosystems are a significant producer of food for humans, livestock feed, as well as a source of phytomass for energy purposes [1,2]
The performed principal component analysis and factor analysis confirm the results of linear regression models for parameters (CPSOM and CSOF)
It was found that the newly used working procedures are consistent with the original methods of fractionation of humic substances

Summary

Introduction

Soil terrestrial ecosystems are a significant producer of food for humans, livestock feed, as well as a source of phytomass for energy purposes [1,2]. Many studies have pointed to the deteriorating quality of agricultural soils. Due to the growing worldwide population and deteriorating environment, an ever-increasing pressure is exerted on the production properties of the soils. The quality of agricultural soils is an increasingly actual topic [3,4,5,6]. Soil organic matter (SOM) is one of the most important factors determining soil fertility. Many previous studies have repeatedly shown the irreplaceable role of SOM. The important roles of SOM in acid buffering were found [10]. The amount of organic carbon in the soil is important in terms of its temporary storage in the soil. Small changes in the soil organic carbon stock could result in significant impacts on the atmospheric carbon concentration [11]

Methods

Results

Conclusion