Glacial rock flour reduces the hydrophobicity of Greenlandic cultivated soils

• Published in: Soil Science Society of America Journal
• Main Authors: Weber, Peter L., Hermansen, Cecilie, Pesch, Charles, Moldrup, Per, Greve, Mogens H., Blaesbjerg, Natasha H., Romero, Gabriela Moreno, Arthur, Emmanuel, de Jonge, Lis Wollesen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Greenland; greenlandic; Igaliku
• Online Access: https://pure.au.dk/portal/da/publications/glacial-rock-flour-reduces-the-hydrophobicity-of-greenlandic-cultivated-soils(c94534ec-9d0c-4c10-abae-529ddaede12d).html; https://doi.org/10.1002/saj2.20505; https://pure.au.dk/ws/files/339717076/Soil_Science_Soc_of_Amer_J_-_2022_-_Weber.pdf; http://www.scopus.com/inward/record.url?scp=85153536207&partnerID=8YFLogxK

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.