Mitigation of Nitrous Oxide Emissions during Nitrification and Denitrification Processes in Agricultural Soils Using Enhanced Efficiency Fertilizers

Through the increasing use of nitrogen (N) fertilizers due to an increasing food demand, the agricultural sector is the main contributor of anthropogenic nitrous oxide (N 2 O) emissions, mainly through microbial processes called nitrification and denitrification. One option to mitigate N 2 O, a major greenhouse gas, is to use enhanced efficiency fertil izers (EEFs). There are different types of EEFs like nitrification inhibitors or controlled- release fertilizers that aim to match the N release from fertilizers with N demands from plants. Parts of the chapter are also dedicated to organic amendments and their effects on N 2 O emissions. Overall, EEFs can improve the N-use efficiency of plants, which has two positive effects. First, farmers can increase their yields, and second, environmental pollution through excessive fertilizer N can be minimized. However, the effectiveness of EEFs strongly depends on numerous factors like land use type, application method, and climate. More studies are needed to establish individual fertilizer plans that are optimized for the prevalent conditions. In conclusion, N 2 O mitigation using EEFs is only advisable when “initial” N 2 O emissions from conventional fertilizers are criti - cally contributing to annual N 2 O emissions. Thus, careful assessment is needed before EEFs are introduced to the system especially when economic and ecologic results are considered.