Effect of grazing exclusion on organic matter content and bulk density of Icelandic soils

Author(s): Qurbonsho Gadoliev
Final project
Year of publication:
Supervisors: Isabel C Barrio , Maria Svavarsdottir , Mathilde Defourneaux
grazing exclusion, soil organic matter, bulk density


Grazing is often considered as one of the main causes of vegetation and soil degradation. Grazing affects the physical, chemical, and biological properties of the soil. The intensity of grazing is an important factor affecting the properties and functions of the soil. High grazing pressure can cause serious loss of soil fertility and productivity as a result of a reduction in vegetation cover and can ultimately lead to soil degradation. One of the most common ways to restore degraded rangelands is through grazing exclusion. To be able to see the effects of grazing exclusion on rangelands I assessed soil organic matter with the Loss on Ignition method, and bulk density in grazed and non-grazed areas in the highlands of Iceland. Soil sampling was conducted at an ongoing field experiment established in the spring of 2016. The soil samples were collected in fenced and non-fenced areas in two different habitats (heath and desert) at two sites (Audkuluheidi and Theistareykir). The results showed that there were no significant differences in soil organic matter or bulk density between fenced and non-fenced areas in any of the sites or habitats. The results indicate that four years of grazing exclusion in grazing areas in the highlands of Iceland is not long enough time to create differences in soil organic matter or bulk density. Nevertheless, such a study can give a better understanding of certain conditions of rangelands that could help improve rangeland management. It is therefore recommended that similar studies should be conducted in Tajikistan. By improving grazing rangelands and their productivity, the herders in Tajikistan might be able to increase their livestock numbers in order to increase their income and thus improve their livelihood.