I have a mixed species plantation, where trees are replaced at irregular intervals. I need a non-pressure compensating adjustable dripper. Max flow 12-16 liters per hour, min flow zero. (0 to 4 gph) I can do this from 1 to 4 by using flag emitters and changing the flag part. But no one makes a 0gph flag. The emitter has to be cleanable.
I don't anything about drippers; but, if nothing else is available, you could use a progammable water timer to turn off the water line when you want the dripper to go to zero.
Alas I am not about to install thousands of programable timers. I do use timers a lot. A zone typically is 300 to 600 1 gph drippers or a single 100 gph sprinkler. My water supply will run 3 sprinklers or 1 drip zone at a time. I try to do all my sprinkling between 5 a.m. and noon, as there is less evaporation loss, and everything is dry by mid afternoon. Less mildew. Picture this: 60 short rows of 10 trees each in my display area. 3 trees get sold. Their drippers now will run onto the ground when the zone is watered. Picture this: Parkland pillar birch is popular this year, so I double up the jack pine and the siberian larch and run 2 rows of PPbirch. So now all the 1 gph drippers have to become 2 gph drippers According to my inventory between trees here, and trees arriving this spring I have 51860 trees. About 2/3 are little guys under sprinklers. Still means a lot of drippers.
