Nitrous Oxide Emissions after Application of Manure-Derived Fertilisers

Research output: Book/ReportPh.D. thesisResearch

  • Kun Zhu
Livestock manure is widely used as nitrogen (N) fertiliser and its application contributes a substantial proportion of N inputs to cropland. One of the major concerns with application of livestock manure is the loss of N through emissions of nitrous oxide (N2O) and the subsequent impact on global warming. This PhD project therefore investigated N2O emissions from soil after application of manure-derived fertilisers with varying spatial distribution, and evaluated the influences of available C, N and O2 on N2O emissions. Fresh, composted and charred manure solids were applied in soil to provide different levels of C availability. The turnover and availability of N was modified by addition of nitrification inhibitor dicyandiamide (DCD) or mineral N. Soil O2 dynamics was monitored with high spatiotemporal resolution to elucidate the related mechanism regulating N2O emissions. Significant differences of N2O emission between different manure-derived fertilisers were observed. The application of fresh or composted manure solids had much higher N2O emissions than that of charred manure solids which contained low available C and N contents. The immature compost with a high content of dissolved organic carbon had higher N2O emissions than fresh manure solids. The addition of mineral ammonium increased soil N availability and generated higher N2O emission, probably due to the induced higher nitrification and associated denitrification as well. DCD addition reduced gross nitrification rates significantly and resulted in lower N2O emission. The spatiotemporal dynamics of O2 in soil, influenced by manure application, was closely linked to N2O emissions. The degree of anoxia in the soil developed faster as the heterogeneity of manure distribution decreased. The faster the anoxia developed, the earlier the peak emission rates of N2O occurred, and also the less the nitrification appeared to contribute to the N2O emissions.
Original languageEnglish
PublisherDepartment of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen
Number of pages133
Publication statusPublished - 2014

ID: 127500049