Plant more than one crop per field (intercropping)
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Planting more than one crop in each field increases habitat heterogeneity at a smaller scale than increasing crop diversity at a landscape scale (see ‘Increase crop diversity’). Heterogeneity is thought to be key for increasing farmland biodiversity and so planting multiple crops may help birds of different functional groups to use a single field.
Supporting evidence from individual studies
A study on two arable farms in Iowa, USA, in May-August 1992-3 (Stallman & Best 1996), found that 35 bird species used fields under an experimental intercropping system, with an average of 108 birds/count/100 ha. Three native species (red-winged blackbird Agelaius phoeniceus, common grackle Quiscalus quiscula and vesper sparrow Pooecetes gramineus) nested in the fields, but that only one nest of forty (2.5%) successfully fledged young. Destruction by farming activities was the largest cause of nest mortality (39%) followed by predation (29%). Desertion only occurred at 5% of nests. Strips were 4.6 m wide and contained corn, soybeans and oats as well as mammoth red clover Trifolium pratense.Study and other actions tested