A healthy soil maintains the four main functions carbon transformations, nutrient cycles, soil structure and regulation of pests and diseases. These soil functions are under threat in intensive agriculture and there is a need for cropping practices ensuring good soil health to maintain and optimize the production capacity of arable soils and a stable crop yield. Cover crops (CC) are plants grown following or together with the main crops for the protection and enrichment of the soil. CCs are known for their beneficial impacts on soil health including impacts on nutrient retention, erosion, soil compaction, soil carbon storage and soil biodiversity. Further, CCs have known beneficial impacts on plant health and the occurrence of soilborne plant pathogens. Yet, little is known about the CC impacts on interactions between soil health and soilborne plant pathogens, including impact of the CCs root exudates (metabolites) on soil health and soilborne pathogens. Root crops are highly affected by large losses due to inadequate crop quality and diseases caused by soilborne pathogens. An adapted use of CCs in root crops could improve biological and physical properties affecting soil health and improve plant health to increase both yield and storage quality. Through Cropdrive, we aim to identify a set of CCs with high potential for improving soil- and plant health in potato and root vegetable production, by (i) assessing how CCs’ primary and secondary metabolites in soil reduce soilborne pathogens and enhance beneficial soil microbes, (ii) mapping the impact from selected CCs on soil health parameters and how these parameters connect to soil metabolites and plant health, (iii) demonstrating the impacts on soil health, soilborne plant pathogens, and potential greenhouse gas (N2O) emissions from including CCs in field-scale potato and root vegetable production, and (iv) assessing the impacts of the CCs on plant health and the harvest- and storage quality of the produce.
The Norwegian agricultural value chain actors for potato and vegetable production aim for a 50% increase of the domestic share within 2035. Carrots and potatoes are important agricultural crops in Norway, but there are major challenges with plant disease both in the field and in storage. Cover crops have the potential to be an important tool for a sustainable increase in vegetable and potato production and there are several recent projects exploring this potential. However, there is a lack of studies that look at how cover crops contribute to good soil health and at the same time consider the effect on soilborne plant pests such as fungi, bacteria and nematodes.
Cropdrive aims to identify a selection of cover crops suitable for use in root vegetable and potato production with beneficial impacts on both soil and plant health, and greenhouse gas exchange. We will test a number of cover crops and measure trends in the occurrence of primary and secondary metabolites, e.g., amino acids, organic acids and phenols in the root zone. We will evaluate how these metabolites affect the growth and quality of potatoes and carrots. Further validation of the proposed cover crops will be done under field conditions in experimental fields and with selected growers, with measurements of selected parameters for good soil health, -structure and -physical conditions, greenhouse gas exchange, occurrence of soilborne plant pests and effects on crop quality in the field and during storage. The output from Cropdrive will provide documented recommendations on the choice of cover crops and necessary adaptations of cropping practices to ensure successful use in root vegetable and potato production. The project will be a collaboration between research institutes, value chain partners (agricultural advisers, farmers associations, industry partners), administrative bodies in agriculture and food safety, and international scientific experts.