Abstract: Topography is a main factor to the uniformity of drip irrigation. The laying length of drip line was calculated under different slope to analyze the relationship between slope and drip line laying length in comparison with that of the flat slope. Water head loss was calculated according to practical layout of drip irrigation district. The formula of flow deviation rate was derived, and the practical inlet pressure of the irrigation district was calculated. The results show that topography has a strong effect on drip line length, drip line length reduces to half while adversary slope is 0.05, drip line length doubles while down slope is 0.05. The pressure of irrigation district calculated by new formula corresponds to actual situation.

Key words: slope, flow deviation rate, pipeline laying length, irrigation plot, inlet pressure