Some measures of reducing leaching loss of nitrates beyond potential rooting zone

Summary Distribution patterns of nitrate in field are studied in twelve treatments comprising of different N splits and irrigation schedules, after the harvest of wheat. Total amount of irrigation and nitrogen application were kept same for each treatment. The curves show that heavy irrigation at greater intervals can result in larger amount of unutilised NO₃ ^–-N, which will eventually be lost beyond potential rooting zone. As irrigation becomes lighter and frequent, nitrates travel slowly and thus remain for more time within the reach of roots and are lost to a less extent. When whole of the nitrogen is applied in one lot, considerably more NO₃ ^–-N is lost under all the irrigation schedules. As the number of splits are increased, susceptibility of nitrate nitrogen for leaching decreases to a greater extent under lighter and more frequent irrigation schedule than the other. Besides N-splitting and irrigation criteria, efficiency and depth of rooting system of plants seems to play a major role in defining nitrate leaching patterns towards unsaturated zone.