A Comparison of High Speed Low Disturbance and Knife Style Ammonia Applicators for Irrigated Corn.

Anhydrous ammonia (AA) is one of the most commonly used nitrogen (N) fertilizer sources for corn (Zea mays L.) in the US. Traditional knife applicators are slow, have high power requirements and create substantial soil disturbance. Thus, there is considerable interest in high speed, shallow placement, low draft AA applicators, particularly for no-till production systems. The objective of this study was to compare a prototype high speed, low draft applicator (HSLD) with a traditional knife type AA applicator (Trad) for irrigated corn production in Kansas.  Six N rates ranging from 0 – 224 kg N ha^-1 in 45 kg increments were applied at 3 application timings, Fall, Preplant (Pre), and Sidedress (SD) with both type applicators. The impact of applicator, time of application and N rate was measured on gaseous NH₃ emissions over a one week period after each application, on  plant stand, N uptake and grain yield. Significant differences in NH₃ losses at high N application rates were seen at some application timings, with higher losses being seen from the shallow placement. However these N losses did not affect grain yield.  A significant response to N was seen.  No difference between applicators was seen in plant stand, N uptake or yield.