ORCID Profile
0000-0002-0788-0712
Current Organisation
Aarhus University
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Publisher: Wiley
Date: 13-02-2022
DOI: 10.1002/SAJ2.20490
Abstract: 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 s les 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.
Publisher: Wiley
Date: 29-04-2022
DOI: 10.1002/SAJ2.20407
Abstract: Soil water repellency (SWR) is a common phenomenon across agricultural soils of South Greenland that can negatively affect soil functions. Existing methods to measure SWR as a function of water content ( w ) are laborious. This study was conducted to compare the potential of visible–near‐infrared spectroscopy (vis–NIRS) as an alternative method to pedotransfer functions (PTFs) for predicting four SWR indices in 143 agricultural soils from South Greenland (clay, 0.016–0.172 kg kg –1 organic carbon (OC), 0.009–0.241 kg kg –1 ). Pedotransfer functions were established by multiple linear regression based on OC, clay, and pH. Partial least squares regression (PLS‐R) and interval PLS‐R were applied to build vis–NIRS prediction models (vis–NIR range 400–2,500 nm). The area under the SWR– w curve (SWR area ) and the critical soil water content ( w non ) were accurately predicted by PTFs ( R 2 = .90 R 2 adj = .91) while the SWR after 60 °C pretreatment (SWR 60 ), and the integrative repellency dynamic index (IRDI) were predicted less accurately ( R 2 adj = .36 R 2 adj = .27). Vis‐NIRS models with variable selection performed at a better or close to the same level of accuracy as PTFs (SWR area , R 2 = .88 w non , R 2 = .90 SWR 60 , R 2 = .63 IRDI, R 2 = .54). This study demonstrated vis–NIRS as a valuable alternative to PTFs for rapid assessment of SWR and as a tool for SWR mitigation for farmers in South Greenland. The results may well apply to other regions with similar texture and OC ranges, but further testing is required.
Publisher: Wiley
Date: 24-04-2023
DOI: 10.1002/SAJ2.20505
Abstract: 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 C bell‐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.
Location: Denmark
No related grants have been discovered for Emmanuel Arthur.