Nitrogen Concentration in Barley and Soil with Different Fertilizer Treatments

The use of waste as a resource is a part of the circular economy concept. Human urine, a readily available human waste, could be a cost effective alternative to conventional mineral fertilizer. However, the feasibility of this application requires testing of the environmental impacts as well as the plants grown with human urine. This thesis aimed to study the nitrogen concentration in the barley crop grown with human urine as nitrogen is one of the most important macro nutrients directly impacting plant growth. Another aim of this thesis was to compare the total nitrogen content between the barley crop treated with human urine and mineral fertilizer. This was done by determining the total nitrogen content of barley grains, straws and barley-grown soil of both treatments. The samples were analysed with two methods: the automatic analyser Elementar vario TOC select and the manual Kjeldahl digestion method. The soil samples were analysed with the vario TOC select while grains and straws were analysed with the Kjeldahl digestion. The test resulted in an insignificant difference in the total nitrogen content across the samples of both treatments as well as when compared to the reference database from the Natural Resources Institute Finland. In addition, the dry weather of summer 2018 negatively affected the barley grain quality of both treatments. The results suggested the feasibility of human urine to replace mineral fertilizer in terms of nitrogen content and the need to further study the effects of weather conditions on barley crops’ nitrogen uptake