Biocontrol of soil-borne phytopathogenic fungi by fungivorous soil fauna communities in organic potato cropping systems
Continental (Germany)
In the continental region, the risk of infestation with soilborne fungal plant pathogens such as Fusarium spec. and Alternaria spec. increases, especially in moist soils, which threatens the quantity and quality of root crops (here: potatoes). This situation leads to higher input use by farmers, which makes the agroecosystem less resilient in the long term and leads to a loss of soil biodiversity. State of the art
In the continental region, increasing infestation pressure from soil-borne plant pathogenic fungi poses growing challenges to agriculture. This situation leads to the use of more inputs even in organic farming, which affects the resilience of agroecosystems. The external input by organic farmers to combat the problem of fungal pest incidence are low-dose copper-based contact fungicides and high tillage intensity, which reduce functional soil biodiversity. Farmers are advised to consider cultivation breaks of 5 years for potatoes in their crop rotation. For economic reasons, the rotation sequence can be tightened down to 3 years. In the short-term, farmers financially benefit more from comparatively high prizes for potatoes. In the long-term, soil conditions are threatened.
Objective
The objective of this case study is (i) to assess the biocontrol potential of fungivorous soil fauna communities and (ii) to promote fungivorous soil fauna communities in potato cropping systems.
Proposed management practices
The potential of strip undersowing (undersowing only in furrows) and broad undersowing (undersowing on ridges and in furrows) to promote fungivorous soil fauna communities and to increase their biocontrol potential in terms of Fusarium and Alternaria and their mycotoxins in organic potato cultivation is assessed.
Progress with the case study in relation with the state of the art
Undersown crops in organic potato cultivation will strengthen soil intrinsic self-regulating processes. A synergistic interaction between farmers’ management (top-down control) and soil fauna services (bottom-up control) for fungal plant pest control (i) protects the soil; (ii) increases system resilience in arable land; (iii) reduces management costs and (iv) makes root crop products economically more competitive by improving product quality and avoiding yield depression.
