You might have noticed a buried plastic bottle next to the sapling in some of your sapling photographs.
This is a WIck's irrigation bottle, which diffuses water directly to the roots of the tree through a wick (cotton rope) inserted at the bottom of the bottle. This technique prevents evaporation of water and dramatically decreases the amount of water needed for irrigation of the tree. It also recycles the bottle.
We plant the bottle beside the tree. Only the neck of the bottle is outside the soil so that we can pour the water in. Most of the bottle is underground. The idea is to water directly to the roots of the tree and not on the surface of the soil to avoid evaporation of water and eventually salinization of the soil.
