Corn uptake of bromide under greenhouse and field conditions

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Abstract
Bromide (Br) has been used frequently to trace the movement of fertilizer derived nitrate (NO3) through the soil profile. Although not required for plant growth, Br is readily absorbed by plants. Consequently, the pulse of an anion tracer moving through the soil can be attenuated by actively growing plants. Greenhouse and field experiments were conducted to determine the amount of Br absorbed by corn, and to better understand potential competitive interactions between nitrogen (N) and Br in plant uptake. Under greenhouse conditions, over 85 percent of applied Brwas recovered by corn tops. Results from both greenhouse and field experiments demonstrated that the addition of Br or Cl neither reduced yield nor inhibited N uptake. Therefore, either Br or Cl could be used in N trials without concern for competitive inhibition of N uptake. However, both experiments demonstrated that N treatments affected Br concentration in the tissue, but this difference may have been due to increased yield of N treated plants causing Br dilution. Nitrogen treatments significantly affected plant Br uptake, but only in the greenhouse study. In the field experiment, corn recovery of 100 kg Br/ha applied in the spring of 1988 was as high as 38 percent in 1988, and 11 percent in 1989. This high rate of recovery demonstrates that the pulse of Br can be significantly reduced in the presence of developing plants, and should be taken into account when it is used as a tracer in leaching studies.