ARE AGROECOLOGICAL CROPPING SYSTEMS SUITABLE FOR TROPICAL HORTICULTURAL CROPS?

Abstract

Nowadays, tropical horticulture is often characterized with a high use of chemicals (pesticides and fertilizers) that may led to both a diffuse and long term pollution of soils and water resources and an acute contamination of fruits and vegetables with pesticide residues. In FWI, this is the case for banana, and to a lesser extent for vegetable and citrus, whose intensive production had local ecological impacts that went beyond social acceptability. Today, new UE and French regulations require the reduction of the use of chemicals to ensure safe production and environment protection, hence enhancing the need for new cropping systems less dependent upon chemicals. Among different alternatives, the design of new horticultural cropping systems based on the concept of ecological intensification that prioritizes ecological processes for the management of horticultural agroecosystems, is a very challenging one. Our approach is both global and integrative, using multicriteria assessment tools. It is focused at the field and farm scales. We propose here a conceptual framework based on the concept of ecological intensification that prioritizes the enhancement of biodiversity and organic status nutrients availability in cropping systems; and illustrate this framework through three case studies in FWI : i) pest control in tomato and banana cropping systems through enhanced plant and insect biodiversity, increased food web complexity and feedback regulations, ii) phosphorus availability in banana potting experiments through earthworms activity , and iii) weed control through cover crops in citrus orchards. Ecological intensification, although at a preliminary stage, is a promising strategy to design sustainable horticultural cropping systems, even in high phytosanitary pressure conditions. (Resume d'auteur)