In more arid areas where drip irrigation underneath mulch is invaluable for orchard and agroforestry applications, what would people suggest is the best way to install an efficient irrigation system which can adjust to the ever changing dripline of trees as they grow? When your trees are small they will need the drippers in one place, but that will change as they grow. What is the best way to build that necessary adjustment into the system at the initial construction stages? If you ring the plants (circular drip feed around dripline) then the rings will need to grow over time - would the necessary estimated 'slack' required to allow this just be left at the end of each line? To me, another alternative is a grid which can 'bulge' in gradually expanding semi-circles at the drip line of each tree...seems a tidier, easier to manage solution than the former, but it also seems it would be require a lot more line to do it. The other thought I had was putting a good sloped circular mound for each tree, so wherever the drippers were, gravity allowed the water to reach the dripline - is that a better solution than moving the lines over time...or a situation where too much water would be needed to reach the dripline than the other above solutions? The system would need to adjust to a wide variety of different sized trees of differing growth speeds and ultimate root spread, so that is a factor which would need to be accounted for in the decision making process. The other major variable is the fact that it's fairly sandy soil which drains quickly. And of course, the whole idea is to keep the amount of water needed for irrigation to a minimum, as most irrigation will be done from collection tanks or fertigation ponds rather than a bore or mains system. I've not needed to solve this problem before (having lived in high rainfall areas), so I'd appreciate any suggestions or advice.