How do I schedule irrigation at the critical stages of my crop to save water?

Saving water is not about watering less everywhere, it is about making sure water is there at the few stages where the crop cannot afford to be thirsty, called the critical or moisture sensitive stages. Most crops have stages like crown root or early growth, flowering, and grain or fruit filling where water stress causes the biggest yield loss. If water is short, protect those stages first and stretch the interval at the less sensitive stages. The exact critical stages differ by crop, for example wheat has its well known first irrigation at crown root, so it is worth getting the list for your specific crop. Combine this with checking the soil before each irrigation so you do not water when the root zone is still moist. Mulching, drip, and even land leveling all stretch the same water further. For the critical stages of your particular crop and a sensible schedule for your area and soil, your KVK or agriculture officer can give you the right list rather than a generic one.