What is drip?<\/strong><\/p>\n\n\n\n Before moving ahead, very briefly let me say what I mean by drip irrigation for fruit trees. I\u2019m using a narrow definition in this post. By drip, I mean a single orifice that emits some water. So you can have a black polyethylene tube that you punch drip emitters into or you can have a poly tube that has emitters built in (\u201cinline\u201d drip tubing, or “dripline”).<\/p>\n\n\n\n But I\u2019m not<\/em> talking about micro-sprinklers, bubblers, little sprayers, or adjustable octopus-type emitters.<\/p>\n\n\n\n Advantages and disadvantages of drip irrigation on fruit trees<\/strong><\/p>\n\n\n\n Some of the advantages of using drip irrigation on fruit trees are that you can use water more efficiently because you are not losing much to evaporation (compared to sprinklers); you can run the irrigation at any time of day because the wind doesn\u2019t affect it (compared to sprinklers); and it\u2019s easy to calculate how much water you are giving each tree (count the emitters and multiply by the output per emitter).<\/p>\n\n\n\n A few of the disadvantages of using drip irrigation on fruit trees are that the emitters can clog, especially those in quarter-inch tubing (emitters in half-inch tubing clog far less, in my experience); your chickens scratch around the tubes and move them; and it can be more work to adjust drip as trees grow bigger (compared to adjustable micro-sprinklers).<\/p>\n\n\n\n Physical layout of tubing and emitters<\/strong><\/p>\n\n\n\n Farmers and gardeners use various ways of laying out tubing under their fruit trees so the emitters are in the right places. I\u2019ve used every one of these methods, and they all work.<\/p>\n\n\n\n If your fruit trees are in a line and close together, I\u2019d choose the single or double lines layout. If not, then pigtails are probably best. I use mostly pigtails (or rings) on my trees.<\/p>\n\n\n\n How drip works<\/strong><\/p>\n\n\n\n For me, it was not obvious that drip irrigation could work to effectively water a fruit tree when I first tried it. How could a tree be satisfied just getting water at a few points under its canopy?<\/p>\n\n\n\n But drip does work. That\u2019s undeniable. I\u2019ve watered so many trees for so many years successfully with drip that there\u2019s not a shadow of a doubt left.<\/p>\n\n\n\n (There are also many large farms across the world attesting to the effectiveness of drip on fruit trees.)<\/p>\n\n\n\n It helps to understand what happens to the drips of water that come out of each emitter. They touch the dirt and then spread laterally. Many times I have measured the lateral spread of drip irrigation in my soil, and here is what it looks like:<\/p>\n\n\n\n So while from the surface it may look like dots of water, just below the surface a much larger volume of dirt is being wetted.<\/p>\n\n\n\n How many emitters<\/strong><\/p>\n\n\n\n Remember this: your fruit tree needs a certain quantity of water more than a certain area wetted. In other words, what is most important is that you give a tree X<\/em> gallons of water; what is less important is at how many points you are applying that water.<\/p>\n\n\n\n I once heard a farm advisor say that he had determined that roughly 60 percent of the soil volume under a tree\u2019s canopy needed to be wetted in order for the tree to produce maximum fruit. I don\u2019t know where he got that estimate, but I keep it in the back of my mind and it seems about accurate based on trees I\u2019ve seen in various locations and other research I\u2019ve read.<\/p>\n\n\n\n For example, a study in Israel on avocados<\/a> found that \u201cenlargement of the wetted soil volume from 25% to 75% increased root growth rate and improved tree water status and transpiration response to high evaporative demands.\u201d<\/p>\n\n\n\n What this means for the number of emitters we use under our trees is that there\u2019s a range of acceptability. There\u2019s no single correct answer. But here\u2019s a simple rule of thumb that will put you within that 60-percent plus range: use at least as many emitters as the tree\u2019s canopy is wide (in feet). In other words, if the tree is ten feet wide, it should have at least ten drip emitters under it.<\/p>\n\n\n\n Following this rule of thumb has brought good results for the trees on drip irrigation in my yard.<\/p>\n\n\n\n Starting newly planted trees on drip<\/strong><\/p>\n\n\n\n When I plant a new fruit tree, I usually give it a single drip emitter. If it\u2019s a bigger new tree though, such as a bare-root fruit tree, I will give it two emitters. However, if any new tree is planted near established plants (e.g. a grapevine, older tree, or native bush), I give the new tree three emitters so it can better compete with the root competition of the established plants.<\/p>\n\n\n\n For the small tree, the emitter must be placed right by the trunk, which is where the tree\u2019s roots are. For the bigger new tree, the emitters can be placed on either side of the trunk, about 6-9 inches away from the trunk.<\/p>\n\n\n\n Here is a video showing how I set up new avocado trees on drip (the method is perfectly applicable to any other kind of fruit tree):<\/p>\n\n\n\n![\"types](\"https:\/\/gregalder.com\/yardposts\/wp-content\/uploads\/2022\/04\/types-of-drip-irrigation.jpg\")
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