Wetting Agent Influence on Water Infiltration into Hydrophobic Sand: I. Rewettability

Song, Enzhan; Schneider, Joseph G.; Anderson, Stephen H.; Goyne, Keith W.; Xiong, Xiaozhen

doi:10.2134/agronj14.0152

Cited by 10 publications

(10 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some reports show enhanced soil water retention and increased water holding capacity compared with untreated material without improved water movement in water repellent soil [ 35 , 36 ]. In contrast, others found improved water infiltration/drainage or lower soil water content in treated hydrophobic soil [ 37 , 38 , 39 , 40 , 41 ]. These results suggest that wetting agents with different chemical properties may act through different mechanisms.…”

Section: Resultsmentioning

confidence: 99%

Certain Soil Surfactants Could Become a Source of Soil Water Repellency after Repeated Application

Song¹,

Goyne

Kremer

et al. 2021

Nanomaterials

Self Cite

View full text Add to dashboard Cite

Repeated application of soil surfactants, or wetting agents, is a common practice for alleviating soil water repellency associated with soil organic coatings. However, wetting agents are organic compounds that may also coat soil particle surfaces and reduce wettability. For this experiment, hydrophobic sands from the field and fresh, wettable sands were collected and treated with either a polyoxyalkylene polymer (PoAP) or alkyl block polymer (ABP) wetting agent, or water only treatments served as a control. Following repeated treatment application and sequential washings, dissolved and particulate organic carbon (OC) were detected in the leachates of both sand systems. The total amount of OC recovered in leachates was 88% or less than the OC introduced by the wetting agents, indicating sorption of wetting agent monomers to soil particle surfaces regardless of soil hydrophobicity status. While ABP treatment did not alter solid phase organic carbon (SOC) in the sands studied, PoAP application increased SOC by 16% and 45% which was visible in scanning electronic microscopy images, for hydrophobic and wettable sands, respectively. PoAP application also increased the hydrophobicity of both sands that were studied. In contrast, ABP treatment increased the wettability of hydrophobic sand. Our results provide strong evidence that certain wetting agents may increase soil hydrophobicity and exacerbate wettability challenges if used repeatedly over time.

show abstract

Section: Resultsmentioning

confidence: 99%

Certain Soil Surfactants Could Become a Source of Soil Water Repellency after Repeated Application

Song¹,

Goyne

Kremer

et al. 2021

Nanomaterials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Due to the high affinity among nonpolar structures, once wetting agents are watered in through irrigation/precipitation, these amphiphilic surfactants attach their nonpolar tails onto nonpolar hydrophobic surfaces, and subsequently increase the overall soil wettability by facing the polar heads toward the by-passing water (Cisar et al, 2000;Dekker et al, 2005;Kostka, 2000). Addition of wetting agents can hence reduce the surface tension of water from 73 to 32 mN m -1 or lower depending on the wetting agent selected and rate used, ultimately facilitating spontaneous wetting and water infiltration into hydrophobic sand (Song et al, 2014a). This effect, however, diminishes over time as the wetting agent molecules degrade, and often repeat applications are needed to maintain soil wettability year-round (Song et al, 2014b).…”

mentioning

confidence: 99%

Surfactant Chemistry Effects on Organic Matter Removal from Water Repellent Sand

Song¹,

Goyne²,

Kremer³

et al. 2018

Soil Science Soc of Amer J

Self Cite

View full text Add to dashboard Cite

Soil surfactants, which represent a wide range of wetting agent chemistries, have been used as the primary tool for mitigating drought issues caused by soil water repellency (SWR). However, the residual effects of soil surfactants are often short-lived, requiring repeated applications. Alternatively, certain groups of wetting agents may remove hydrophobic organic matter for extended control of SWR. This laboratory study investigated the effects of selected wetting agent chemistries, including products of alkyl block polymer (ABP), nonionic surfactant + acidifiers (NIS), and polyoxyalkylene polymer (PoAP), for removing organic matter and reducing SWR. Naturally-occurring hydrophobic sand was packed into sand columns and subjected to wetting agent application. The treated columns were then washed three times with deionized water, and the volume of the leachates from each wash event was determined. Sand treated by PoAP showed enhanced water-holding capacity, although the effect diminished after the second wash. In comparison, ABP resulted in 2.3-fold greater output of combined dissolved organic carbon (DOC) and particulate organic carbon (POC) in the leachates than PoAP, and made the hydrophobic sand completely wettable. Alternatively, NIS showed similar effects compared with the control. Although PoAP reduced SWR to a minimum level, it was sorbed strongly to the sand, which resulted in 27% greater solid phase organic carbon (SOC) in treated sand, compared with the untreated control. However, the exact mechanisms underlying surfactant effects on DOC and POC are unclear and the long-term effects of surfactants following repeated application in the field are yet to be determined.

show abstract

“…These results indicated a superior effect of AE, ABP, and PoAP for SWR mitigation, compared to other wetting agents included in this experiment. Previous research reported that hydrophobic sands treated with certain wetting agents, such as AE, maintained their wettability for an extended period, compared with other compounds such as PXL [28]. Table 2.…”

Section: Soil Vwc Lds and Swrmentioning

confidence: 99%

Influence of Repeated Application of Wetting Agents on Soil Water Repellency and Microbial Community

Song¹,

Pan²,

Kremer

et al. 2019

Sustainability

Self Cite

View full text Add to dashboard Cite

Wetting agents are the primary tool used to control soil water repellency (SWR) and localized dry spot (LDS), especially on sand-based soils. However, the effect of repeated applications of wetting agents on soil microbial populations is unknown. This two-year field experiment investigated six wetting agents representing different chemistry effects on a creeping bentgrass (Agrostis stolonifera L.) putting green with existing SWR. Four out of the six wetting agents improved soil volumetric water content in the second growing season, while others showed no effect. This result was negatively correlated to the development of LDS, and positively correlated to occurrence of an air-borne turf disease. Soil microbial populations, determined by soil phospholipid fatty acid (PLFA) analysis, found that none of the treatments applied caused a shift in microbial populations between fungi and bacteria, or gram-positive and gram-negative bacteria. The stress indicators such as saturated to mono-unsaturated fatty acids were not affected by the wetting agents applied as well. However, the wetting agent that contains alkyl block polymers (ABP; Matador) with proven capability for removal of soil organic coatings showed inhibition of microbial populations at one evaluation timing. This result suggested a temporary restriction in soil carbon availability for soil microorganisms following repeated ABP application, which likely contributed to the elevated LDS development observed. Another wetting agent, a combined product of a nonionic surfactant plus acidifiers (NIS; pHAcid), which is designed to reduce inorganic carbonates while enhancing wetting, elevated all soil microbial populations tested at the end of the experiment, indicating a desirable improvement in soil health. However, repeated application of NIS did not reduce SWR at the conclusion of this experiment, which, in combination with a previous report, suggested a minimal disturbance of soil organic coatings of the hydrophobic sand. Overall, this experiment suggested that soil microbial populations can be affected by wetting agents which may further influence SWR, yet the actual effect on soil microorganisms varies depending on the chemistry of the wetting agents.

show abstract

Wetting Agent Influence on Water Infiltration into Hydrophobic Sand: I. Rewettability

Cited by 10 publications

References 29 publications

Certain Soil Surfactants Could Become a Source of Soil Water Repellency after Repeated Application

Certain Soil Surfactants Could Become a Source of Soil Water Repellency after Repeated Application

Surfactant Chemistry Effects on Organic Matter Removal from Water Repellent Sand

Influence of Repeated Application of Wetting Agents on Soil Water Repellency and Microbial Community

Contact Info

Product

Resources

About