Effects of N fertilization and weed density on availability and uptake of Zn in soil and maize

In order to evaluate effects of different levels of N fertilization on availability and uptake of Zn in soil and maize (Zea mays L. var. S. C. 602)، in condition competition with redroot pigweed (Amaranthus retroflexus L.) an experiment in factorial design with 3 replications was conducted at west of Tehran. Factor A consisted of three levels of N (142، 190 and 237 kg/ha) and factor B was three levels of redroot Pigweed densities (0، 5 and 25 plant/m-2). Results showed that with increasing nitrogen application، Zn uptake by corn increased، but not by weed. Zn uptake by corn was significantly higher in 5 weed/m2 compared to no weed. In according to these results، weed density under critical level، not only is not disadvantage for crop، but also it can increase Zn uptake and so seed yield.