Research interests

With the aim of reducing nitrogen (N) losses to the environmental, my research interests are the use and utilization of N in animal manures, sewage sludge and mineral fertilizers for crop growth. Also studies of phosphorus (P) and micronutrients (Cu, Zn and Mn) and heavy metals in these N sources have my interest. The alphanumerics refer to my papers that may be found in the publication lists.

Animal manures
Equipment for carrying out field experiments on animal slurry has been constructed ( A1, C1, D2, E1) and used for studies on ammonia volatilization ( A2, E3) and the crop response to different applications methods ( A21, B5, B6, D18, D19, F7, F8, F15, F36, F37). Also the effect of application method on weeds has been studied (C2, D1, F10). The fertilizer value of nitrogen and use of animal manures has been treated in several publications ( A3, C10, C15, E6, E25, F5, F9, F10, F11, F17, F18, F26, F27, F28), in particularly the publications E9 and E31.

Issues on storage ( A24, B2, F6) and treatment (E23, E24, F42) of animal manures as well as the consequences for the soil in using copper (Cu) and zinc (Zn) in the feed for pigs ( A20, F40) have been studied. The effect of acidified slurry on availability of soil manganese (Mn) has been tested ( A23, F33, F41). EU-directives and Governmental actions plans have caused comprehensive legislations in Denmark and I have discussed some topics in B10-B12, D9 and F14.

Sewage sludge
The main topic has been the fertilizer value of N and agricultural use of sewage sludge ( A12, D6, D8, D10, E7, F19-F23, F25, F31, F32), but some publications also deal with heavy metals (C3, C5, E4) and organic contaminants ( A12, A13 ).

Mineral fertilizers
The main topic concerned placement of the nitrogen fertilizer in relation to the crop row, often using 15N techniques ( A6, A7, A15, D11, E11, E20, E21, F24, F29, F30), but also placement of phosphorus has been studied (C14, C16, C18, D23, D30, F47) and manuscripts for peer-review are in preparation. Experiments on placement of 15N-enriched animal slurries are reported ( A21, D20, E15, F39) and placement of acidifying mineral nitrogen fertilizers for improved availability of soil Mn (D29, F43, F44). Types of nitrogen fertilizer and their soil reactions are described in general (F16).

Inter-species ( A9, A18, C7, D12, D13, D17, F34, F35) and intra-species ( A19, D17) competition for 15N applied by placement has been studied based on ideas from earlier field experiments on herbicide-free growing of malting barley ( A4, A22, D4, D5).

The crop response to fertilizer N residuals has been studied in long-term experiments ( A25, A26, C11, D24, D26). Heavy metals in mineral fertilizers are reported in C12/C13 and E34-E39.

Interdisciplinary topics
I've been responsible for management and statistical handling of data from The Askov Long-Term Experiments (LTE) on Animal Manure and Mineral Fertilizers (D21, D27, E27, F13) and in general I'm interested in LTEs as a unique platform for research on soil chemistry and nutrient availability to crops (D25, E29, E30, F45).

Variations owing to sampling procedure and chemical analysis has naturally been integreded with my research activitites. Thus variation in nutrient concentrations has been studied in plants, manures and fertilizers ( A17, E16, E38) as well as pesticide concentration in water courses ( A27 ).

In addition to my experimental works focusing on utilization and uptake of applied N sources, also N balance studies including losses by nitrate leaching has been carried out for organic and mineral nitrogen sources (B1, B7, B8, C8/C9, D7, D22, E17, E28).

During the 1990s, winter wheat became a dominant cereal crop in Denmark and I've been involved in the nutrition part of the publications ( A5, A8, A10, A11, D3, D31/D32, E2, E40-E43 ). However, I used spring wheat for studing the effect of application time ( A16, F38).

In an innovative project collaboration with a private company (a SME), the cultivation of soya beans has been tested recently for Danish conditions (D28, D33, F46, F48-F53).

I find statistical methods for exploring experimental results (A1-A26) as well as analyzing monitoring data for unravelling purposes (e.g. E5, E10, E42, E43) very interesting, and different SAS procedures, including macro-programming, have been used in the above-mentioned publications.

My qualifications include:

·   Agricultural knowledge - specialized in nutrient cycling and animal manures
·   Knowledge of the principles of law with interest in environmental law and EU directives
·   Data handling, statistics and modelling
·   Project management of short and long-term projects


  A.  Scientific papers in international journals (peer-reviewed)
  B.  Scientific papers i Danish journals (peer-reviewed)
  C.  Contributions to international conferences
  D.  Contributions to national and Nordic conferences
  E.  Reports
  F.  Papers in farmer's journals

Most of the papers are available as pdf-files.
Send an e-mail , and I'll reply with the requested papers.