Pea root rot

Last changed: 06 December 2023

Effects of brassica intercrops on soil structure, disease suppression, rhizobia efficiency and crop growth

Project manager: Kerstin Berglund, Department of Soil Sciences, SLU

Project group: Anna Mårtensson, Department of Soil Sciences, SLU; Paula Persson, Department of Crop Production Ecology, and Desiree Börjesdotter, The Rural Economy and Agricultural Societies.

The EU requirement that all animal feed used in organic production must be organically produced means that production of legumes will have to be improved so as to achieve higher and more stable yields. However, pea growing is surrounded by problems: soil compaction, nutrient deficiency in the establishment phase and attack of pea root rot caused by Aphanomyces euteiches are some of the issues that make pea growing difficult.

In this project, we will be working from the following hypotheses:

  • Ineffective rhizobial bacteria contribute to prolonging the establishment phase of peas and thereby lower crop reliability.
  • Direct incorporation of biomass from a growing glucosinolate-containing species has a green manuring and soil structure promoting effect, and also an inhibitory effect on A. euteiches, thereby limiting the development of pea root rot.

In greenhouse experiments in large crates of non-infected soil, we will study under controlled conditions how growing and incorporation of intercrops with different glycosinolate concentrations affect pea plant establishment, soil structure, soil biology, nitrogen availability and development of pea root rot. The soil in the crates will be inoculated with A. euteiches and rhizobial bacteria.

  • Growth and development of the pea crop will be monitored during the experiment,
  • soil structure will be characterised,
  • the effect on the rhizobial bacteria will be determined
  • and pea root rot symptoms will be recorded.

The project will be associated with a reference group consisting of growers and crop production advisors. In the project we will combine expertise from soil physics, soil biology, plant pathology and crop production with consideration of experiences and ideas from practice. A postgraduate student will be associated with the project.


Interest in intercrops such as oilseed radish and mustard is currently very great. These species are interesting from a soil structure perspective, as green manures and as catch crops. Because of their high glycosinolate content, after chopping and incorporation into the soil they can form isthiocyanates, which inhibit soil-dwelling crop pests. The complex problems associated with pea growing make it necessary for a number of disciplines to work together to produce results that can be applied in practical pea cultivation.