Anyone who has looked out the windows of an airplane flying over semi-arid agricultural land has seen them. An artile at Edible Geography examines the question of what to do with the spaces between the circles. Insert smaller irrigated circles, or...
These overlooked corners make up a not insubstantial percentage of a farmer’s available land. On a typical 160 acre “quarter section” in the American mid- and southwest, tessellating pivot circles will leave up to 24 acres, or 15 percent of each field, thirsty...As a butterfly enthusiast, I'll cast my vote for allowing just a little bit of the earth uncultivated, as a reservoir for native plants and native wildlife.
That was in the beginning. Today we can certainly solve that problem because we have the means of putting an attachment on the end of a typical system. It will swing out and retract as the system goes around so that the corners are covered. Well, the problem with that is that arm that swings out and all the equipment that goes with it is quite expensive.Mathematics offers another possible solution: Farey-Ford circle packing, a tessellation technique... Elsewhere, a Utah farm family has found a niche leasing corners from their neighbours to grow less thirsty crops or graze cattle... And, increasingly, ecologists are preaching the potential of pivot corners. In a simplified landscape of monoculture crop circles, the corners can restore complexity: left as native perennial grassland or managed as early successional habitat, these concave triangles can provide valuable habitat for bees, birds, and predatory insects to support crop pollination and natural pest control. Sewn together across an agricultural landscape, the corners can even offer movement corridors for migrating species.
Addendum: A hat tip to reader charlie for remembering the relevant Biblical injunction:
"When you reap the harvest of your land, moreover, you shall not reap to the very corners of your field nor gather the gleaning of your harvest; you are to leave them for the needy and the alien. I am the Lord your God.”