Water repellency prediction in high‐organic Greenlandic soils: Comparing vis–NIRS to pedotransfer functions

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The increasing salinization and sodification of soils in drylands and irrigated systems present a great challenge to agricultural production and threaten soil quality. There is an urgent need to investigate potential strategies to remediate soils that are threatened by these processes. To address this challenge, the current study investigated the effects of organic and inorganic amendments and leaching fraction (LF) on physical and hydraulic properties including the soil water characteristic curve (SWCC), Dexter's index of soil physical quality (SDexter), bulk density (BD), saturated hydraulic conductivity (Ks), and water repellency index (RI) in a saline‐sodic soil. A greenhouse experiment was carried out in a completely randomized design with two factors (amendment and LF). The amendments included superabsorbent (1%) (SA), zeolite modified with CaCl2 (2%) (ZC), biochar (2%) (B), biochar + manure (2%) (BM), and a control (no amendment) (CT), and combined with two levels of LF (15% and 30%). Spring wheat (Triticum aestivum, ‘UG99’) was planted in the soil columns. After harvest, undisturbed samples were collected from each column for the determination of soil properties. The results demonstrated the effectiveness of the SA and organic amendments to enhance Ks and decrease BD. There was a significant (p < 0.01) positive effect of the amendments, particularly biochar and superabsorbent on the soil pore size distribution. The SA amendment significantly increased soil water retention, especially at high matric potentials (i.e., 0 to −80 hPa). The effect of organic amendments on the SWCC was in between those of the ZC and SA amendments. The SA and BM treatments were sub‐critically water repellent, while the ZC treatment increased soil water repellency. The SA, B, and BM15 treatments exhibited very good physical quality (SDexter > 0.05). The relative air and moisture capacities were optimal in the B‐amended soil at field capacity (matric potential –330 hPa). We conclude that B, BM, and SA are suitable amendments for reducing the adverse effects of salinity and sodicity via an improvement in soil physical quality.

Section: Soil Water Repellencysupporting

confidence: 69%

“…(2015). Several studies have reported that soil water repellency increases as OM increases (Blaesbjerg et al., 2022; Li et al., 2013). This was not the case in our study as the OM was correlated to S W positively and RI negatively (Table S9).…”

Section: Discussionmentioning

confidence: 99%

Biochar, manure and superabsorbent improve the physical quality of saline‐sodic soil under greenhouse conditions

Fouladidorhani

Shayannejad

Mosaddeghi

et al. 2023

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“…The literature predominately consists of archaeological and geomorphological studies (e.g., Adderley & Simpson, 2006; Jakobsen, 1991; Massa et al., 2012; Schofield et al., 2010). The anticipation of a warmer climate has prompted a renewed interest in these soils, focusing on their nutrient availability (Caviezel et al., 2017), structural development (Pesch et al., 2021), gas diffusion characteristics (Weber et al., 2020), mechanical properties (Pesch et al., 2020), and soil–water repellency (Blaesbjerg et al., 2022; Weber et al., 2021). The soils are generally characterized by a relatively coarse particle size distribution, high organic carbon (OC) contents, and poor structural development (Jakobsen, 1991; Pesch et al., 2021; Weber et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

Organic carbon controls water retention and plant available water in cultivated soils from South Greenland

Weber

Blaesbjerg

Møldrup

et al. 2023

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The warming climate is rapidly changing the circumpolar region, presenting new opportunities and challenges for agricultural production in South Greenland. The warming climate is projected to increase the frequency of drought periods, but little is known about the soil-water retention (SWR) and the plant available water (PAW) of the agricultural soils in the region. This study aimed to measure the SWR and PAW of Greenlandic agricultural soils and evaluate the effect of organic carbon (OC) and clay (CL) content using pedotransfer functions based on OC and CL. The study included 464 South Greenlandic agricultural soil samples from 20 fields with a wide distribution in clay (0.016-0.184 kg kg −1 ) and OC contents (0.006-0.254 kg kg −1 ). Pedotransfer functions were successfully developed for estimating the gravimetric water content (w) at five soil-water potentials (−1500, −100, −30, −10, and −5 kPa) and PAW. The OC content was the primary variable governing the gravimetric water content at each soil-water potential, evidenced by R 2 values consistently above 0.80.The effect of OC on the gravimetric water content at −1500 kPa was close to the range reported in the literature, but OC effects were markedly higher between −100 and −5 kPa. Overall, this study highlights a substantial effect of OC on the PAW as a 1% increase in OC increased PAW by more than 4%, which is almost twice the value of a recent meta-study. Our study highlights the potentially dominating effects of organic matter on soil-water balance and availability in high-latitude agriculture.

“…While the majority of the studies on WR originate from semiarid and Mediterranean climates, it is becoming increasingly evident that WR also occurs in wetter and colder climates (Doerr et al., 2000; Fu et al., 2021; Hermansen et al., 2019; Seaton et al., 2019). A recent study on soils collected across 23 pasture and cultivated fields in South Greenland revealed that 99% of these soils were water repellent, with 98% of the soils being capable of reaching an extremely high degree of WR (surface tension <40.9 mN m −1 ) (Blaesbjerg et al., 2022; Weber et al., 2021). The high prevalence of WR in these subarctic soils was ascribed to a combination of coarse particle size distribution and high OC content (Weber et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Glacial rock flour reduces the hydrophobicity of Greenlandic cultivated soils

Weber

Hermansen

Pesch

et al. 2023

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Soil water repellency (WR) is ubiquitous across Greenlandic cultivated fields, which may constrain agricultural production. Fine-grained glacial rock flour (GRF) is available in the surrounding landscape, which could serve as a soil amendment. We tested whether the application of GRF (rates of 0, 50, 100, 300, and 500 ton ha −1 ) reduced the WR across two field trials in South Greenland. The field trials, Upernaviarsuk (UP) and South Igaliku (SI), differed in clay (UP: 0.05-0.11 kg kg −1 ; SI: 0.03-0.05 kg kg −1 ) and organic carbon (OC) contents (UP: 0.04-0.13 kg kg −1 ; SI: 0.01-0.03 kg kg −1 ). We measured WR across gravimetric water contents (W) from oven-dry to the W where WR ceased (W NON ) to obtain whole WR-W curves. Most soils became hydrophilic around air-dry conditions at application rates of ≥300 ton ha −1 , likely due to increased clay:OC ratios. Application rates of ≥300 ton ha −1 generally reduced the trapezoidal integrated area of the WR-W curve (WR AREA ), W NON, and WR after heat treatments at 105˚C (WR 105 ) and 60˚C (WR 60 ). The WR 105 was significantly reduced in both fields at 500 ton ha −1 , while WR 60 was significantly reduced in UP at application rates of ≥300 ton ha −1 . The GRF effects were masked by texture and OC variations. Normalizing WR AREA to the water vapor sorption isotherms (utilizing the Campbell-Shiozawa model) revealed that GRF consistently reduced the normalized WR AREA . The SI field showed the largest reduction in the normalized WR AREA , likely due to its lower OC and clay contents. Thus, GRF could reduce WR across two Greenlandic field trials.