The banding method. Old school method of appoint fertilizer around palm trees mainly. You still see it from time to time but research has show that it's better to broad cast the fertilizer. This avoid the product from clumping up and allows each workable pebble( there is. Better. Word) to work its way into the soil.
You get asked to investigate the reason behind the death or the decline of plants, its not always easy just to point one thing that is wrong. But in these pictures it was fairly easy to see why the decline. A small hint. The corprit behind the decline is not visible.