Keywords: Cover Crops, Legumes, Soil Carbon Storage and Stabilization, Roots, Biological N2-fixation.
Cover crop mixtures including legumes recycle nutrients, reduce N-leaching, and increase N availability and soil fertility for following crops (De Notaris et al., 2021). In a long-term crop rotation experiment, soil C and N inputs from cover crop mixtures (+/- legumes and +/- cover crop history) were measured, giving rise to differences in soil fertility (Mortensen et al., 2021). For the following lupin-barley intercrop, raw data were collected on dry matter yield, protein content, botanical composition, and N-leaching for the full period. This data will be compared to long-term yield and N-leaching data from earlier legume-cereal intercrops within the same experiment, to assess the effects of cover crop history and mixtures. The project is data-driven, while also providing the opportunity for the student to visit and become familiar with the crop rotation field experiment at AU Viborg. Supervisors will assist on data analysis, preferably in R, and the thesis includes knowledge building on legumes and biological N2 fixation (Martins et al., 2024; 2025).
Is field work part of the topic (yes/no)? No
Is lab work part of the topic (yes/no)? No
Is coding part of the thesis topic (yes/no)? To the extent that statistics may be done in R.
The project is a 30 ECTS project with potential for being adjusted to 45 or 60 ECTS.
Project start is flexible, suggested start is autumn 2026 or spring 2027.
The project work will take place in AU Viborg with possibilities of working remotely.
30 ECTS (IMSOGLO and Agrobiology): Theoretical thesis based on literature studies and/or analysis of issued and edited data sets.
45 ECTS (Agrobiology): Experimental theses in which the student is responsible for collection and analysis of his/her own original data
60 ECTS (Agrobiology): Experimental theses in which the student is responsible for planning, trial design and collection and analysis of his/her own original data
Suggested reading:
De Notaris C., Mortensen E.Ø., Sørensen P., Olesen J.E., Rasmussen J. (2021) Cover crop mixtures including legumes can self-regulate to optimize N2 fixation while reducing nitrate leaching. Agriculture, Ecosystems & Environment 309. DOI: 10.1016/j.agee.2020.107287.
Martins J.T., Bloch N.F., Enggrob K.L., Liang Z., Harbo L.S., Rasmussen J., Peixoto L. (2024) Cover crop mixtures enhance belowground carbon input and suppression of spontaneous flora under Danish conditions. Geoderma Regional 39. DOI: 10.1016/j.geodrs.2024.e00879.
Martins J.T., Peixoto L., Giannini-Kurina F., Han E., Rasmussen J. (2025) Effect of additional inoculation on in situ biomass, nodule formation and N2 fixation in soybean under Northern European conditions. Plant and Soil 518:197-210. DOI: 10.1007/s11104-025-07988-1.
Mortensen E.Ø., De Notaris C., Peixoto L., Olesen J.E., Rasmussen J. (2021) Short-term cover crop carbon inputs to soil as affected by long-term cropping system management and soil fertility. Agriculture, Ecosystems & Environment 311. DOI: 10.1016/j.agee.2021.107339.
