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Title: ANHYDROUS AMMONIA DISTRIBUTION DURING FIELD APPLICATION

Author
item HANNA, H
item WHITE, MICHAEL
item Colvin, Thomas
item BAKER, JAMES

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2002
Publication Date: 4/3/2002
Citation: HANNA, H.M., WHITE, M.L., COLVIN, T.S., BAKER, J.L. ANHYDROUS AMMONIA DISTRIBUTION DURING FIELD APPLICATION. APPLIED ENGINEERING IN AGRICULTURE. 2002. V. 18(4). P. 443-451.

Interpretive Summary: Precision agriculture or 'putting the right thing at the right place at the right time' will depend on equipment that is properly calibrated and puts out the same amount across the width of the machine. Anhydrous ammonia application as a nitrogen fertilizer source has been shown to have problems both with calibration and uniformity of application. This work was done to test the uniformity of application of several commercial manifolds used for the application of anhydrous ammonia in agricultural fields. The manifolds tested varied in their uniformity depending on the rate of application with a tendency toward more uniform application at higher flow rates. Knives were also tested with the data showing that it would be useful to match knives within a set to increase the odds of uniform application across the width of the machine. Having a machine that dependably applies a uniform rate of material should lead to the operator having sufficient confidence to apply the needed amount of material without over application as a hedge against non-uniform patterns. This should have both economic and environmental benefits.

Technical Abstract: Poor knife-to-knife distribution, observed in stationary tests, is a concern because it may reduce efficiency of use and even lead to intentional over application of nitrogen (N) applied as anhydrous ammonia. To determine the magnitude of this problem more accurate data are needed. Ammonia distribution by conventional, Vertical-Dam, and Cold-flo manifolds and flow division by a pipe tee were tested during field applicator operation with ammonia flows from each port caught in water. Due to limitations of the manifolds and regulator, flow variability due to knife style and condition was determined in a stationary test using water instead of ammonia. Port-to-port variability was less for a Vertical-Dam manifold than a conventional manifold at a 56 kg N/ha (50 lb N/a) application rate, but similar for both manifolds at application rates of 112 and 168 kg N/ha (100 and 150 lb N/a). The Cold- flo manifold also had similar variability to the other two manifolds at the 112 kg N/ha (100 lb N/a) rate. Manifolds exhibited a tendency for greatest ammonia output from ports across from incoming flow, intermediate output from ports behind incoming flow, and least output from ports on either side of the manifold midway between these regions. A straight entry pipe did not improve distribution for a conventional manifold. A pipe-tee divided flow evenly, with only an average 2.4% flow difference. Different knife styles had different flow rates suggesting knives, particularly new ones, should be carefully inspected and matched on the applicator.