A1 Journal article (refereed)
A large one-time addition of organic soil amendments increased soil macroporosity but did not affect intra-aggregate porosity of a clay soil (2024)

Rasa, K., Tähtikarhu, M., Miettinen, A., Kähärä, T., Uusitalo, R., Mikkola, J., & Hyväluoma, J. (2024). A large one-time addition of organic soil amendments increased soil macroporosity but did not affect intra-aggregate porosity of a clay soil. Soil and Tillage Research, 242, Article 106139. https://doi.org/10.1016/j.still.2024.106139

JYU authors or editors

Publication details

All authors or editors: Rasa, Kimmo; Tähtikarhu, Mika; Miettinen, Arttu; Kähärä, Topi; Uusitalo, Risto; Mikkola, Jarmo; Hyväluoma, Jari

Journal or series: Soil and Tillage Research

ISSN: 0167-1987

eISSN: 1879-3444

Publication year: 2024

Publication date: 16/05/2024

Volume: 242

Article number: 106139

Publisher: Elsevier

Publication country: Netherlands

Publication language: English

DOI: https://doi.org/10.1016/j.still.2024.106139

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/95212

Publication is parallel published: http://urn.fi/URN:NBN:fi-fe2024052032986

Abstract

Soil structure is a dynamic property which controls a wide range of soil functions and is closely linked with soil carbon content. The carbon contents of agricultural soils are subject to several ongoing trends, including declining carbon stocks and attempts to increase the soil carbon reserves. In this study, we aimed to quantify how organic soil amendments, which have been shown to reduce long-term nutrient loads from agricultural fields, can impact soil structure. The structural impacts of a large one-time addition (8 tons carbon per hectare, three different soil amendments) of pulp and paper mill side stream sludges to a boreal clay soil were explored quantitatively in aggregate (X-ray microtomography, sample size 1–2 mm), core (water retention measurements, sample size 195 cm3) and column (macropores ≥80 µm, sample size ∼ 20 dm3) scales. Our results showed no micrometer-scale structural changes within soil aggregates despite the large number (25 aggregate per treatment) of imaged samples. However, the organic soil amendments had a statistically significant impact on the macroporosity. The macroporosity was on average 20–27 % higher compared to the control samples and visible even five years after the application of the amendments. Such change in soil structure improves soil aeration and fast infiltration of water during wet periods and extreme rain events and may thereby also reduce erosion risk by decreasing surface runoff. The increased microporosity was visible only in the column scale. No statistically significant differences were observed in the fraction of large pores in core scale water retention measurements. Probing the soil structural changes in macropore regime by X-ray tomography or developing sub-micron scale analysis methods are recommended approaches to improve our understanding of clay soil’s structural changes induced by organic soil amendments.

Keywords: soil; clay soils; clay; structure (properties); porosity; organic material; carbon sequestration; tomography; soil physics

Free keywords: soil structure; clay soil; organic soil amendments; X-ray tomography; aggregate; helium ion microscope

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Ministry reporting: Yes

Reporting Year: 2024

Preliminary JUFO rating: 2