Description of the Business As Usual (BAU)
The general soil management in olive orchard is conventional tillage or bare soil with herbicides, sometime mixed with minimum tillage. This system avoids leaving the inter-row with any vegetation to avoid water consumption and any competition with the trees.
Description of the system change
Groundcovers (the term ‘cover crops’ in woody crop is also found in the literature) consists of maintaining spontaneous flora to cover soil in the area between tree rows. This maintains a permanent soil cover year-round and promote crop diversification in the farm. Groundcovers must be controlled by mechanical mowing, chemical spraying or grazing in spring when olive trees are in a phenologically sensitive stage such as flowering. Along the season more than one control may be necessary. The control timing would change according to meteorological conditions but it must be taken care of the main crop to avoid competition. At least a strip should be left alive until it sets seed to allow self-seeding the next season, anyway the emergence must be assessed. In this regard there are species with more self-seeding capacity. With spontaneous flora the species have different cycles setting the seeds at different periods.
Sometimes there is low seed bank in the soil, especially when the BAU used pre-emergence herbicide. Seeding groundcovers is recommended in this case.
The weed control in the tree row should be conducted as BAU. Herbicide control is the common system through spryer with the central nozzles locked to keep the groundcover in the inter-row. Other strategies are also usual like mowing with adapter mower, hand brush cutter or grazing. In super-intensive orchards (1200–2500 trees/ ha) inter-vine mower/blade is also used to remove weeds by mowing or tilling the crop row.