Why is my drip giving uneven water, near plants get more and far plants get less?

Uneven output, where plants near the head get plenty and the far ends get little, almost always comes down to pressure loss along the line or a design and clogging problem. As water travels down a lateral the pressure drops, so if the laterals are too long, too thin, or the field slopes the wrong way, the far drippers get less. The fixes start with diagnosis: if the whole far end is weak, it is likely a pressure or design issue; if it is patchy, it is likely clogging. For pressure, the proper solution is pressure compensating drippers, which give the same flow across a wide pressure range and are essential on long runs and sloping land. Other remedies are shortening the lateral length, using a larger diameter sub-main, splitting the field into smaller zones so each lateral is shorter, and checking the pump gives enough pressure. For clogging, flush the laterals from the open ends, clean the filter, and do an acid or chlorine treatment if there is scale or slime. Check the pressure at the head and at the far end with a gauge to confirm the cause. If the design itself is wrong, ask the vendor to revisit the lateral length and dripper type, ideally moving to pressure compensating drippers.