Examples

Rotation in market gardening

• Basic principles :
  • avoid growing a plant of the same family twice in a row in order to limit the spread of pests and diseases that are often specific to a family.
  • avoid cultivating a plant twice in a row for the same organ (fruit, leaf, root) in order to export different mineral elements. Fruit vegetables have significant requirements in phosphorus elements, leafy vegetables in nitrogenous elements and root, tuber and bulb vegetables in potassium elements.
  • plant gourmet crops such as eggplant, cabbage, cucumber, squash, potato, tomato at the head of the succession in order to enhance the supply of organic matter. It is recommended to carry out crop successions in decreasing order of crop requirement.
  • alternate plants that smother weeds or allow weeding (tomato, pea, potato) with plants with little coverage or that do not allow weeding (carrot, turnip, onion) in order to limit weeding of the plots.
  • wait long enough before growing the same plant again in the same place.
    
    
• Examples of interesting species to include in the rotation: peas and beans to enrich the soil with nitrogen, peanuts, radishes or turnips to trap nematodes, marigold ( Tagetes sp.) to repel nematodes.
• Examples of recommended rotations: cucumber / yam / arugula / pepper, parsley / pepper / radish / bean, tomato / lettuce / sweet potato / corn, cabbage / radish / pea / lettuce, etc...
• Examples of rotations to avoid: tomato/tomato, eggplant/tomato, solanaceae/cucurbitaceae.

Cultural associations 

When several species are grown in association, they necessarily compete for access to water, light and nutrients. Technical choices limit this competition and develop the complementarity of the species brought together.

• Choice of species: plants draw soil elements differently depending on their root system. Herbaceous plants with fasciculate roots explore the most superficial layers, herbaceous plants with taproots (carrot, legumes) use a volume located a little lower and perennial woody species (woody legumes) explore the deep layers of the soil.
• Choice of varieties: within the same species, certain varieties lend themselves better than others to intercropping. For example, corn with upright leaves shades the associated crop less than corn with horizontal leaves.
• Choice of planting dates: the needs of a crop vary according to its stage of development. Competition between associated cultivated species is likely to be all the stronger when their periods of maximum need coincide. „„Crop cycles can be staggered:
  • in intercropping, a short-cycle crop is planted between the rows of the longer-cycle plant, spaced in the usual way (examples: radish x lettuce, cabbage x eggplant, cucurbits x citrus).
  • in the catch crop, a first crop is planted and then a second when the first has reached the reproductive stage but has not yet been harvested. The second crop develops unhindered by the harvest of the first.
• Choice of planting densities: excessive dominance of one crop can lead to poor yield of the associated crop. Interesting yields are generally obtained with planting densities lower than those used in pure crops.
• Choice of spatial organization: setting up the association in alternating rows is the easiest to manage with respect to cropping operations. Row orientation is important when one species is taller than another. The east/west orientation improves the sunshine of the low culture.