This research is astonishing to me! I always thought that sagebrush (
Artemisia filifolia) were competing for water and cleared them out of the food production gardens (they are abundant in other areas of the yard). The nearby sagebrush could explain why the garden next to the shrubs is so much more productive compared to areas where I've cleared the sage.
Seeing is believing: the plot in the article with the shrubs is remarkably more productive:
"Millet grown in conjunction with Guiera senegalensis (left) towers over millet grown without shrubs interspersed among the stalks in this agricultural research field outside Thiès, Senegal. Research shows that planting Guiera senegalensis shrubs in farmers' fields can increase crop yields as the shrubs' roots help pull water deep in the soil closer to the surface."
Nick Roll, NPR
Unless someone has contrary info, my new strategy involves heavily pruning the sand sage but keeping the plants in the food production garden.