Restoring Eroded Lands in Southern Iceland: Efficacy of Domestic, Organic Fertilizers in Sandy Gravel Soils

• Main Author: Brenner, Julia Miriam, 1989-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2016
• Subjects: Umhverfis- og auðlindafræði; Gróðurfar; Rof; Jarðvegur; Landeyðing; Iceland
• Online Access: http://hdl.handle.net/1946/26200

Since settlement Iceland has faced severe soil degradation due to a combination of natural stressors – glacial flooding, volcanic eruption, and heavy wind – and anthropogenic stressors – grazing livestock, wood harvesting, and land use change. Declining soil stability under these conditions resulted in extensive soil erosion: 40% of Iceland now has considerable, severe, or extremely severe erosion. Fertilizers have been utilized for land reclamation in Iceland for many years, but they have mostly been imported, chemical fertilizers. By-products of existing Icelandic industries, such as livestock farming, offer organic fertilizers that could simultaneously reduce erosive forces while making use of a waste product. Restoring vegetation, decreasing soil loss, and encouraging natural succession would increase ecosystem resilience, ensuring longevity and capacity to regulate ecosystem services. This study investigated vegetation and soil changes by three incrementing depths (0-5, 5-10, and 10-20 cm) in Geitasandur, a degraded sandy desert in south Iceland, five years after applications of various fertilizer treatments: a single- and triple application of imported, chemical fertilizers, three types of domestic, organic fertilizers – bone meal, sewage sludge, and chicken manure – and an untreated control scenario. Vegetation cover in control plots at Geitasandur was quite sparse, but increased significantly in triple-chemically treated plots, primarily in the form of moss, as well as vegetation height. Available nitrate, nitrite, and phosphorus concentrations were negligible in all treatments, but triple-chemical plots exhibited greater amounts of ammonium than the control, single-chemical, chicken manure and sewage. Bulk density, carbon content and soil organic matter were not affected by the treatments, but as vegetation progresses it is likely that differences between treatments will become apparent, and soils with higher vegetative cover will acquire greater amounts of carbon and organic matter. Other research ...