Precision Agriculture Research
Corn Grain Yields and Fertility

Lower corn yields and increasing soil residual nitrate indicate that there may be underutilization of the pre-plant urea on the precision ag portion of the field relative to the farmer managed portion of the field where the N was applied as anhydrous at the V6 stage. Heavy spring rainfall in 2003 (143 mm prior to emergence) likely leached a portion of the pre-plant N.

Average N amounts applied to plots by treatment, including farmer managed area.

Urea was applied pre-plant to precision ag plots and anhydrous was applied at V6 to the farmer managed portion. Total includes 56 kg ha-1 applied through irrigation system.

Corn grain yields for precision ag plpots by treatment and farmer managed average yield.

The south half of the field where the farmer managed N applications has a different soil type that has shown to be more productive.

Fall residual soil nitrate-N.

Soil N increased dramatically at the 60-120 cm depth in 2003, indicating possible leaching of pre-plant urea past the root zone.