Evaluation of Nitrogen Absorption and Use Efficiency in Relay Intercropping of Winter Wheat and Maize

In order to evaluate the effect of nitrogen absorption and use efficiency in relay intercropping for winter wheat and maize, a field experiment was conducted during 2008-2009 at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran. A randomized block design with three replications was used. Treatments included four combinations of relay intercropping of wheat and maize (three rows of wheat + one row of maize (3:1), three rows of wheat + two rows of maize (3:2), four rows of wheat + two rows of maize (4:2) and six rows of wheat + two rows of maize (6:2)) and their monoculture. Results indicated that the effect of relay intercropping on the absorbed nitrogen, nitrogen relative absorption, nitrogen absorption and use efficiency of maize and wheat was significant (p≤0.05). The highest and the lowest nitrogen absorption efficiency of wheat and maize were observed in three rows of wheat + two rows of maize (33.70 and 36.50 kg tissue N content kg-1 soil N) and monoculture (14.73 and 19.37 kg tissue N content kg-1 soil N), respectively. Range of nitrogen relative absorption of intercropped wheat and maize were 1.47-1.08 and 0.41-0.54, respectively. Nitrogen use efficiency of wheat and maize were 88.62 and 147.33 kg seed N content kg-1 tissue N content, respectively. In general, relay intercropping of winter wheat with maize increased nitrogen absorption and use efficiency.