The impact of different land uses in urban area on humus quality

Abstract

Purpose In urban areas, humus quantity and quality depend less on natural environmental factors than on anthropogenic ones. The aim of the study was to assess the impact of different land use types of urban soils on the properties of soil organic matter (SOM). Materials and methods Thirty-five sites involving four ways of soil use were examined: lawns, allotment gardens, fallows, and arable lands. The study was conducted in Pruszków Town in the Warsaw Agglomeration, Central Poland. Lawns and allotment gardens were located in the central part of the town, whereas fallows and arable lands were in the peripheral zones. Humus horizons, to a depth of 0-20 cm, were analyzed. Using Na-pyrophosphate extraction, we determined the soluble SOM compounds (PY), and the organic matter in the extraction residue, considered as humins (HM). In a separate extraction (with 0.05 M H 2 SO 4 ), low molecular weight (LMW) humus compounds were determined. The quantity of humic acids (HA) precipitated during Na-pyrophosphate extraction was determined as well. A spectroscopic method (UV-Vis) was used to characterize HA properties. The absorption coefficients E4/E6 were calculated based on the results of absorbance measurements involving 465-and 665-nm wavelengths of UV-Vis light. Statistical analyses were performed to find similarities and differences between soils differently used in Pruszków. Results and discussion The dominant part of the humus in the studied soils were humins HMs. There were two times more HM in the central part of the town than that in the peripheral zones. The same observation was made for soluble humus compounds (PY). The amount of LMW fractions was similar in soils of all uses. The degree of humification was small and averaged about 30% for all soils. Fulvic acid (FA) concentrations predominated over HA concentrations in all soils. The least condensed HA occurred in the allotment gardens with an E4/E6 ratio of 5.7, whereas the most condensed HAs were present in soil on arable lands (E4/E6 ratio of 4.7). Conclusions The studies have shown that the type of land use affects humus properties. The main differences were found to be in the quantity of humus compounds. Soils from the central part of the town contained more stable (HM) and soluble (PY) compounds than soils in the outskirts of town. PY compounds were characterized by a simple structure. Fulvic acids (FA) dominated in all of the studied soils (low HA/FA ratio). A high E4/E6 ratio indicates low maturity of humic fractions with low molecular weight compounds.

Pollution Assessment Based on Element Concentration of Tree Leaves and Topsoil in Ayutthaya Province, Thailand

“…For example, Horváth et al [ 30 ] found radial increase in soil organic matter content from the city center in Sopron city, Hungary. On the contrary, Oktaba et al [ 31 ] observed that soils from the center of Pruszkóv Town in Poland contained more humic substances than those from the outskirts.…”

The Valorization of Biolignin from Esparto Grass (Stipa tenacissima L.) Produced by Green Process CIMV (Compagnie Industrielle de la Matière Végétale) for Fertilization of Algerian Degraded Soil: Impact on the Physicochemical and Biological Properties

“…In our case, we add that our value may correspond to dominant fulvic acid (FA) concentrations compared to humic acid [37], and this can perhaps be explained by a phenomenon of the degradation of organic matter and degradation of biolignin. The higher the E4/E6 ratio, the more unstable the organic matter, with aliphatic structures and small size with a higher content of functional groups [41].…”

“…Ultraviolet-visible spectroscopy was carried out in the present study to reveal the degree of humification. This technique is widely used for determining the molecular properties of humic material (humic or fulvic acids) by the ratio E4/E6 calculation, which provides important information on the structure of humic acid [36,37]. According to Reddy et al [38], the E4/E6 ratio is used as a significant humification index.…”

“…All other authors suggested this value of ratio E4/E6 indicates that the fraction of fulvic acid has a lower molecular weight and aromatic condensation. Many studies show that the E4/E6 ratio varies inversely with molecular weight (PM), with a lower PM characterizing fulvic acids [37].…”

Preface: humic substances in the environment

“…HSs influence on the soil aggregate stability is shown by Kobierski et al (2018) as well as by Pollakova et al (2018). Problems with land use and the state of the SOM are discussed by Kwiatkowska-Malina (2018), Menšik et al (2018), Oktaba et al (2018), and Ukalska-Jaruga et al (2018). Additional two papers deal with lake sediments, including the application possibilities of delayed luminescence method for the characterization of HSs (Mielnik and Asensio 2018), and using excitationemission matrix fluorescence with PARAFAC model for optical characterization of HA (Mielnik and Kowalczuk 2018).…”