Organic carbon controls water retention and plant available water in cultivated soils from South Greenland. Issue 2 (13th February 2023)

• Record Type: Journal Article
• Authors: Weber, Peter L.; Blaesbjerg, Natasha H.; Moldrup, Per; Pesch, Charles; Hermansen, Cecilie; Greve, Mogens H.; Arthur, Emmanuel; de Jonge, Lis Wollesen
• Is Part Of: Soil Science Society of America Journal. Volume 87:Issue 2(2023)
• Page Start: 203
• Page End: 215
• Publication Date: 2023-02-13
• Subjects: Soils -- United States -- Periodicals; Soil science -- Periodicals; Periodicals; 631.4973
• DOI: 10.1002/saj2.20490
• Languages: English
• ISSNs: 0361-5995

Abstract

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 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. Core Ideas: This is the first comprehensive study measuring the soil–water retention (SWR) of Greenlandic agricultural soils. The SWR and plant available water (PAW) were determined for 464 soils originating from 20 agricultural fields. Pedotransfer functions were developed to evaluate the effect of organic carbon (OC) and clay content. OC was the primary variable governing the SWR of these subarctic soils, especially at matric potentials ≥−100 kPa. The impact of OC content on the SWR and PAW was high compared to the literature.