Fractal planting patterns yield optimal harvests, without central control

Bali’s famous rice terraces, when seen from above, look like colorful mosaics because some farmers plant synchronously, while others plant at different times. The resulting fractal patterns are rare for man-made systems and lead to optimal harvests without global planning.

To understand how Balinese rice farmers make their decisions for planting, a team of scientists led by Stephen Lansing (Nanyang Technological University) and Stefan Thurner (Medical University of Vienna, Complexity Science Hub Vienna, IIASA, SFI), both external faculty at the Santa Fe Institute, modeled two variables: water availability and pest damage. Farmers that live upstream have the advantage of always having water; while those downstream have to adapt their planning on the schedules of the upstream farmers.

Read more at: https://phys.org/news/2017-06-fractal-patterns-yeild-optimal-harvests.html#jCp

They don’t say why fractal patterns are optimal.

Tau.Neutrino said:

Fractal planting patterns yield optimal harvests, without central control

Bali’s famous rice terraces, when seen from above, look like colorful mosaics because some farmers plant synchronously, while others plant at different times. The resulting fractal patterns are rare for man-made systems and lead to optimal harvests without global planning.

To understand how Balinese rice farmers make their decisions for planting, a team of scientists led by Stephen Lansing (Nanyang Technological University) and Stefan Thurner (Medical University of Vienna, Complexity Science Hub Vienna, IIASA, SFI), both external faculty at the Santa Fe Institute, modeled two variables: water availability and pest damage. Farmers that live upstream have the advantage of always having water; while those downstream have to adapt their planning on the schedules of the upstream farmers.

Read more at: https://phys.org/news/2017-06-fractal-patterns-yeild-optimal-harvests.html#jCp

more …

“Here, pests enter the scene. When farmers are planting at different times, pests can move from one field to another, but when farmers plant in synchrony, pests drown and the pest load is reduced. So upstream farmers have an incentive to share water so that synchronous planting can happen. However, water resources are limited and there is not enough water for everybody to plant at the same time. As a result of this constraint, fractal planting patterns emerge, which yield close to maximal harvests.”

To me, this result looks startlingly like a recent study in to optimising traffic light timing. It was found that optimal traffic flow in some circumstances occurred when traffic light timings were not regular (like synchronous planting) or random, but more like a fractal arrangement.

Although “fractal” is probably too strong a word to use here.