Soil organic matter and clay zeta potential influence aggregation of a clayey red soil (Ultisol) under long-term fertilization

Abstract

The effect of soil organic matter (SOM) on aggregation of variably-charged red soils (Ultisol) through clay zeta potential is not fully understood. Therefore, the objectives of this study were to investigate the SOM effect on the clay zeta potential and soil aggregation after fertilization. Soils under 17 years of fertilization (manure, NPK + straw, NPK, and control (CK) were adjusted by KCl solution to reach varying soil pH and concentration in order to determine clay zeta potential, cations, and aggregate size distribution. The SOM content and C-functional groups by 13C-NMR analysis were also determined. Results showed that the negative zeta potential displayed a bell-shaped pattern with increasing concentration of KCl, but displayed different amplitude of variation among treatments. Manure had the highest zeta potential value and its degree of variation in relative to the value at KCl concentration of 0.1 mol L−1 (19%), NPK + straw and NPK treatments were similar, and CK was the least. Greater negative zeta potential for manure treatment was attributed to higher SOM content, aromatic-C functional groups, and their greater concentrations of Ca2+ and Mg2+ than did the CK. As a result, higher SOM and clay zeta potential yielded in less release of amount of soil particles (< 10 μm) (r = − 0.46*) and enhanced water stable macroaggregates for manure instead of NPK + straw. Long-term manure fertilization would be suggested as a conservation practice for red soil due to its increase in soil aggregate stability and negative zeta potential in subtropical climate.

Coupled high and low-frequency ultrasound remediation of PFAS-contaminated soils

“…In comparison, the zeta potential of the nanobubbles generated in sonication treatment was −14.92 ± 1.34. The surface of the soil minerals is usually negatively charged; similar results has been reported in several other studies [68] , [69] , [70] , [71] . Concurrently, the surface of the nanobubbles is also usually negatively charged [52] , [72] , [73] .…”

“…The zeta potential for soil 1 and 2 were −48.68 ± 4.24 and −83.12 ± 12.49, respectively. Organic matter in soil 2 would have decreased the zeta potential of the particles [68] . In comparison, the zeta potential of the nanobubbles generated in sonication treatment was −14.92 ± 1.34.…”

“…The soil slurry was then transferred to a 1 L graduated cylinder, filled to volume with DI water, mixed, and left to settle [65] . Clay particles (<2 μm) were pipetted from 5 cm below the water surface after having settled for 24 h [66] , [67] , [68] , [69] . To measure the zeta-potential of the nanobubbles generated during the sonication process, the reactor chamber was filled with 1.5 L distilled water followed by ten minutes of sonication [48] , [70] , [71] .…”

Fractionation and transport of compost‐derived dissolved organic matter fractions in saturated red soil and black soil columns

“…Generally, higher pH and higher SOM content contributed to the less positive Zeta potential of soil (Asadi et al., 2009; He et al., 2021). Besides, the Fe/Al oxides had high isoelectric points (i.e., Fe oxide: 8.1–8.5 and Al oxide: 9.4) (Fisher‐Power & Cheng, 2018; Tang et al., 2010), and thus the higher content of free Fe/Al oxides in red soil is expected due to the less negative Zeta potential of red soil.…”

Land use impact on soil structure of Pseudogleys in southern Mačva and Pocerina, Serbia

“…Consequently, the correlation analysis indicated a connection between the aggregate composition and stability of structural aggregates of the studied Pseudogleys and their substances are considered to be persistent cementing agents related to the formation and stabilization of soil aggregates, where their molecular composition plays a predictive role in the soil aggregation process (Fei et al, 2021). According to He et al (2021), free and occluded light soil organic carbon (SOC) play major roles in macroaggregate stability, probably because the positive effect of SOC on van der Waals attractive force between soil particles can limit the release of microaggregate.…”