I have young citrus and fruit trees that range from 2 to 4 ft planted in the ground on a slope. I have 2 one gph emitters for each tree and water them every 3 days for 3 hours. Giving the trees 6 gallons every 3 days. Do the 2 emitters cover enough of the root zone? I was thinking of switching to a micro spinkler that gives 13 gph and running it for 30 mins instead. That way the root zone is covered more and they are still getting 6 gallons every 3 days. The trees seem to be doing fine right now and are growing and flowering.
Citrus and Fruit Tree Watering
Here's an article on citrus watering: https://www.gardeningknowhow.com/edible/fruits/citrus/tip-on-water-requirements-for-citrus-trees.htm
The soil's drainage and moisture retention properties are the main factor in determining how much water is enough. The way to determine how deeply you are watering is to dig, an hour or so after the watering has been done. Get into that soil with a shovel - it should be moist at least 1/2 again the depth of the root ball, moist enough that when you squeeze the soil in your hand, it should stick together, but not all muddy and full of free water.
I would not feel comfortable watering a 4' newly planted tree only 6 gallons, unless I had investigated the soil and knew for sure it was enough.
As the article suggests, watering once a week but much more water would be my choice. And I would use a system that spread the water widely enough to cover all the root area, and beyond.