Pedosphere (2): 638--654, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Optical properties of soil water-extractable organic matter respond to changes in irrigation water quality |
Mikhail BORISOVER1 , Asher BAR-TAL1, Nadezhda BUKHANOVSKY1, Anna BEREZKIN1, Marcos LADO2, Guy J. LEVY1 |
1 Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion 7505101 (Israel)
2 Centro de Investigaciones Científicas Avanzadas, Facultad de Ciencias, Universidade da Coruña, A Coruña 15001 (Spain) |
| Corresponding Author:Mikhail BORISOVER |
| ABSTRACT |
| Treated wastewater (TWW) irrigation may harm soil and agricultural production. Adverse effects of TWW irrigation may be mitigated by changing irrigation water quality, e.g., use of fresh water (FW), or management, e.g., lower-frequency irrigation (LFI) with TWW. The influence of mitigation treatments on soil organic matter and water-extractable organic matter is unknown. To examine this influence, a study was conducted in an avocado orchard irrigated from 2009 with secondary TWW. Four parallel treatments were applied for six years (2016-2021), involving irrigation with FW, a 1:1 FW-TWW mixture, TWW at LFI (twice a week), and TWW irrigation three times a week as control. Soil samples from three depths were characterized for total organic and inorganic carbon and nitrogen and using Fourier-transform infrared spectra that were decomposed into components by nonnegative matrix factorization. Aqueous extracts of soil samples were characterized for dissolved organic carbon (DOC), inorganic carbon, and nitrogen concentrations, absorbance at 254 nm (Abs254), and excitation-emission matrices of fluorescence that were decomposed into components by parallel factor analysis. The Abs254 and fluorescence of humic-like components in the soil extracts were the attributes most consistently responding to irrigation water quality. Irrigation with FW and a 1:1 FW-TWW mixture led to decreases in the concentrations of aromatic and humic-like constituents in the soil extracts compared with the control TWW irrigation. Changing soil irrigation management had no or little impact on those attributes compared with the control TWW irrigation. Results of the study support the use of optical properties related to the concentrations of ultraviolet-absorbing and light-emitting constituents in soil extracts, rather than the whole DOC concentration, as sensitive descriptors suitable for evaluating soil response in different agricultural scenarios. |
| Key Words: fluorescence,Fourier-transform infrared spectroscopy,humic-like substances,nonnegative matrix factorization,parallel factor analysis,specific ultraviolet absorbance,treated wastewater |
| Citation: Borisover M, Bar-Tal A, Bukhanovsky N, Berezkin A, Lado M, Levy G J. 2026. Optical properties of soil water-extractable organic matter respond to changes in irrigation water quality. Pedosphere. 36(2): 638-654. |
| |
|
View Full Text
|
|
|
|
