Multicriteria evaluation of the pathological resilience of in-soil protected cropping systems.

Cropping systems in in-soil protected cultivation are often very intensive andare characterized by a very low number of crops in the rotation. They are thereforevery fragile with respect to soil-borne pests and diseases, and depend on pesticides.These cropping systems must be redesigned to exploit pesticide free techniques tocontrol these soil-borne pests and diseases. Because these techniques (soilsolarisation, chosen intercrop or manure, biofumigation, tolerant cultivars…) arenot totally effective, they must be combined to add their effects. Although thesetechniques are described in the R&D literature, few systems approaches areavailable to describe their combined effects. Part of this knowledge, though, is heldby advisers and growers combining these techniques on farm. Building on thehypothesis that this local knowledge can be combined to the available scientificliterature, we design a multicriteria tool to evaluate the properties of candidatescropping systems in in-soil protected cultivation. The properties that are qualifieddeal with the resilience of the cropping system with respect to the main occurringpests and diseases, and with the environmental impact of the cropping system,taking into account several pests at once. Because the knowledge of the growers andadvisers is more qualitative than quantitative, we have chosen a qualitativemulticriteria approach. We present here the knowledge and evaluation tree built inthe specific case of in-soil protected cultivation cropping systems common in SoutheastFrance, cropping systems based on winter salad crops (from 1 to 3 successivecrops) associated to a spring cash crop (melon, cucumber, eggplant…). The mainpests addressed in this presentation are root-knot nematodes. We advocate then thatsuch a tool can be used with growers and advisers to redesign cropping systems andselect the promising ones that will be put into trial in R&D stations.