PRECISION SIDEDRESS UAN APPLICATION FOR CORN PRODUCTION O k l a h o m a S t a t e U n i v e r s i t y Kefyalew Girma Oklahoma State University

O k l a h o m a S t a t e U n i v e r s i t y Introduction O k l a h o m a S t a t e U n i v e r s i t y Nitrogen Leak

O k l a h o m a S t a t e U n i v e r s i t y Introduction O k l a h o m a S t a t e U n i v e r s i t y Coulter UAN application in corn (Ames, IA). UAN surface application is made within the center of the row, 15 inches away from the base of each stalk. The common use of UAN for sidedress N application in corn is to apply this liquid fertilizer in the middle of rows using either dribble surface bands, or rolling coulter injection.

O k l a h o m a S t a t e U n i v e r s i t y Introduction O k l a h o m a S t a t e U n i v e r s i t y Excavated corn plants showing no overlapping of nodal root systems when corn plants were more than 10” apart, at silking growth stage

O k l a h o m a S t a t e U n i v e r s i t y Objective to compare three sidedress N placement methods on corn grain yield/where Evaluate sidedress N rates O k l a h o m a S t a t e U n i v e r s i t y Sense by plant and treat based on yield potential

O k l a h o m a S t a t e U n i v e r s i t y Treatment structure of precision sidedress UAN experiment, Haskell and Lake Carl Blackwell, 2005-2006. Trt Pre Side d. Placement method 1 40 20 Directed stream application at the base of each plant (1) 2 Directed stream application at the base of a row (2) 3 Dribble surface bands applied in the middle of two rows (3) 4 5 6 7 80 8 9 10 160 11 12 13 NA 14 Broadcast 15 200 O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y By-row By-plant O k l a h o m a S t a t e U n i v e r s i t y Between rows

Directed Stream Applicator O k l a h o m a S t a t e U n i v e r s i t y Directed stream application of UAN in corn applied at the base of stalk of the plant

Design and Field Layout W E N S Location: Haskell-2005 4 5 2 9 10 15 7 8 3 13 12 11 14 6 1 III 1 14 15 6 5 7 13 9 4 3 8 10 11 2 12 II O k l a h o m a S t a t e U n i v e r s i t y 13 5 10 4 15 12 8 9 7 2 3 6 14 11 1 I Plot size 10’ x 20’ with 5’ alley By plant N rate was determined as: Calculate UAN/row Divide the above by number of plants/row

O k l a h o m a S t a t e U n i v e r s i t y Between row and within row by plant corn grain weight variability at Haskell (Hask) and Lake Carl Blackwell (LC), OK, 2005. Row Mean dry grain weight, lb/plant Percent of no. of plants with yield > mean Range, lb/plant Standard deviation lb/plant Hask LC Haskl 1 0.20 0.38 50 53 0.31 0.35 0.09 2 0.19 47 0.34 Pro ns O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y Between row and within row by plant corn grain weight variability at Haskell (Hask) and Lake Carl Blackwell (LC), OK, 2006. Row Mean dry grain weight, lb/plant Percent of no. of plants with yield > mean Range, lb/plant Standard deviation lb/plant Hask LC Haskl 1 0.21 0.20 45 41 0.41 0.53 0.12 0.11 2 0.19 46 40 0.43 0.55 0.13 Pro ns O k l a h o m a S t a t e U n i v e r s i t y

Martin et al. (2005) Agron. J. 97:1603-1611 Regardless of yield level, plant-to-plant variability in corn grain yield can be expected and averaged more than 2765 kg ha-1 (44 bu/ac) over 46 sites (Ohio, Iowa, Nebraska, Virginia, Mexico, Argentina)

O k l a h o m a S t a t e U n i v e r s i t y Effect of UAN sidedress placement method on corn grain yield O k l a h o m a S t a t e U n i v e r s i t y

Effect of sidedress N rates on corn grain yield O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y Summary Within row variability in grain yield was very high By plant sidedress application of N according to individual plant yield potential would result in improved efficiency and reduced cost to producers The gain in yields from the three methods ranged from 7 to 25% more than the broadcast treatment in three location-years O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y Summary Under normal growing conditions, N should be sidedressed by plant at a rate of 20-40 lb/A to maintain yield level and decrease loss in fertilizer N concurrent with within row plant to plant variability Results are not conclusive as the 2006 corn growing season was extremely dry/hot The experiment will be continued for 1 more year O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y Summary Additional measurements such as ears per plant, 100-seed weight, ear size, plant spacing, and grain N concentration O k l a h o m a S t a t e U n i v e r s i t y

O k l a h o m a S t a t e U n i v e r s i t y THANK YOU! O k l a h o m a S t a t e U n i v e r s i t y