Keywords : : cropping system, participatory method, fruit production, citrus, orchard, cover plants, beneficial organism-plant interaction, crop association, West Indies, tropical plantation

Introduction of sanitizing plants in citrus orchards in the West Indies—an example of a participatory innovative cropping system design initiative

A participatory method for designing and assessing innovative cropping systems is currently being tested by the CIRAD HortSys research unit with the aim of reducing herbicide treatments in citrus cropping systems in the West Indies. The constraints of the current system were assessed and potential improvements determined with stakeholders. In response, different grass cover management prototypes were created with annual and perennial strategies. These prototypes, which were first tested in a research station, are based on the use of cover plants (of the pea and pulse family) or the selection/preservation of natural grass cover that interacts more beneficially than competitively with the citrus crop. The main targeted ecological services involve reducing erosion hazards and creating beneficial fauna refuges. The main constraint to be dealt with is water competition between the grass cover and the cash crop. These prototypes are compared through a multicriteria evaluation that includes different agroenvironmental and socioeconomic indicators. Apart from the balance of inputs consumed by the different prototypes (water, energy, chemical inputs, labour, etc.), we are studying these prototypes with respect to their ecosystem disturbance potential. Phytoseiid mites were chosen as bioindicators (common, many species, highly susceptible to disturbances, not very mobile, etc.). Simpson’s reciprocal index and abundance were used to assess the impact of the prototypes on populations of this bioindicator and to determine levels of disturbance associated with the different grass cover management practices. These prototypes, once validated, are implemented in citrus grower’s orchards. The multicriteria evaluation indicators developed in our project will be used to design a decision-support tool to enable growers to assess their own production systems so as to determine ways that they could be improved and become more sustainable.