The invention relates to a composite sheet for protecting field-cultivated subsistence or horticultural plants, which is remarkable in that said composite sheet includes a first flexible, light-transparent, synthetic material sheet (1), at least one area (11) of which is perforated, and at least one flexible, airtight, light-transparent, synthetic material sheet (2) attached to the first sheet (1) such as to be detachable in portions and to sealably cover the or each perforated area (11) of the latter. Said second sheet is manually or mechanically detachable.
