The influence of phosphorus on the tolerance of maize (Zea mays L.) to atrazine

Glasshouse and field studies were conducted to examine the effect of high phosphorus (P) application on the tolerance of the maize cultivar SSM2041 to atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-tria- zine]. Two glasshouse experiments were conducted. In one, seedlings were exposed to five P concentrations and in the second, low (3:12) and high (12:3) NH4 +:NO3-N ratios were combined with 310 and 403 mg P L−1, respectively. In the field study, fertilizer [3:2:1 (25%) + Zn] was band-placed in the field in a Hutton soil (15% clay) at levels of 150, 200, 300, 405 and 600 kg ha−1. Atrazine was applied at levels of 0.5 and 15 mg L−1 in the glasshouse experiments, while rates of 0, 2.5, 5.0, 7.5, 10, 12.5 and 15 kg ai ha−1 were used in the field. It was found that the tolerance of maize seedlings to atrazine was not influenced by fertilizer levels in the field. Under glasshouse conditions, high P levels alone did not significantly affect the tolerance of maize seedlings to atrazine. Growth was signifi...