Abstract
This study was conducted to compare the effect of different field slopes (0.0, 0.1, 0.2 and 0.3 percents) on nitrate-nitrogen (NOrN) distribution in surface irrigated fields. To achieve this, advance time of irrigation water, average nitrates in the soil layers at different border sections, irrigation distribution and application efficiencics were determined. The results showed a significant effeet of slopes on the distribution of nitrate-nitrogen and irrigation water. Zero graded fields gave more uniform distribution of NOrN and irrigation water than the other slopes. Nevertheless, fields having gradient of 0.1 % also gave results similar to zero graded fields. Increased slopes caused accumulation of NOrN and irrigation water towards downstream side of plots.
