CROP ROTATION AS A SYSTEM APPROACH FOR SOIL FERTILITY MANAGEMENT IN VEGETABLES

This paper reviews the recent literature on crop rotation as a tool to manage soil fertility specifically for vegetable production. All of the aspects dealing with soil fertility management, i.e. mineral and organic fertilisation, crop residues management, cover cropping and green manuring, and intercropping, are examined in the frame of crop rotations in conventional and organic systems for both specialised and non-specialised vegetable production. A focus is given on conservation tillage practices to manage green manures and vegetable crop residues. The design and modelling of vegetable rotations are described under the viewpoint of increasing the nutrient use efficiency and the self-sufficiency of the system. Some long-term experiments including vegetables are described which evaluate cumulated effects of rotations on soil fertility and vegetable production. It is concluded that only integrating all the available techniques of soil fertility management at a whole rotation scale it is possible to contribute to the productive, economic and environmental sustainability of the system. For example, little supplementation of mineral or fast-release organic fertilisers delivered with rational fertilisation techniques (e.g. starter, split, and localised fertilisation; fertigation) may help compensate the temporal and spatial lack of matching between nitrogen release from slow-release organic sources and crop nitrogen demand. This would help modulate nutrient supply in a more flexible way and improve crop nutrient uptake, so allowing more constant yields across years and limited risks of nutrient loss to the environment.