Fallow

Definition

A period during which cultivated land is deliberately left unsown to restore soil fertility, conserve moisture, and break cycles of crop pests and soil-borne pathogens by depriving them of host plants. In entomological and ecological contexts, fallow fields create temporary early-successional habitats that support distinct arthropod assemblages, including ground beetles (Carabidae), spiders, and pollinators, while simultaneously suppressing specialist crop pests.

Etymology

Old English fealu, fealh, referring to plowed but unsown land; akin to Old High German felga 'fallow land'.

Example

In integrated pest management, a two-year fallow rotation in Australian wheat systems reduces populations of the redlegged earth mite (Halotydeus destructor) by eliminating host legumes, while fallow strips in European agroecosystems enhance spider diversity and biological control of cereal aphids.

Related Terms

• crop rotation
• fallow field ecology
• early-successional habitat
• pest suppression
• conservation headland
• set-aside

Usage Notes

Distinguish from the adjective fallow describing the pale brownish-yellow coat color of fallow deer (Dama dama). In entomology, 'fallow' typically describes the land management practice and its ecological consequences rather than the color. Contrast with set-aside (often longer-term, policy-driven) and bare fallow (repeated cultivation to suppress all vegetation, less favorable to beneficial arthropods). The ecological value of fallow for arthropods depends strongly on duration, vegetation regrowth, and landscape context.