Liquid Nitrogen Fertilizers In Spring Wheat.

Multiple liquid nitrogen (N) fertilizer products are currently marketed as more efficient, advantageous N sources. Proposed benefits of liquid N products include increased N use efficiency (NUE), higher yields and, and savings in money, labor and time to wheat producers. When evaluating use efficiency of spring wheat production systems, combining yield and protein into protein yield makes sense because N is vital to both yield and protein production. The objective of this study was to evaluate the effect of liquid N fertilizer sources, rates and dilution ratios on spring wheat grain yield, grain protein content, protein yield N uptake and N use efficiency (NUE). This study was initiated in the spring of 2012 at three locations: two dryland - at Western Triangle Agricultural Research Center, Conrad, MT and in a cooperating producer’s field (Jack Patton, Choteau County, MT), and one irrigated - at Western Agricultural Research Center, Corvallis, MT using Choteau spring wheat. At planting, 90 kg N ha^-1 was applied as urea. At Feekes 5 growth stage, 56 kg N ha^-1 was applied to wheat canopy utilizing an all-terrain vehicle (ATV)-mounted stream-bar equipped sprayer. Three liquid N sources – urea ammonium nitrate (UAN), liquid urea (LU), and high NRG-N (HNRGN) and three dilution ratios of fertilizer%/water% - 100/0, 66/33, and 33/66 - were evaluated. While similar grain yields were obtained with LU and highNRG-N at dryland sites, lowest yields were achieved with UAN. At the irrigated site, UAN and highNRG-N produced similar yields and the lowest yields were obtained with LU. There was no apparent trend in grain protein content associated with fertilizer N source. At both dryland sites superior protein yields were observed highNRG-N, while at the irrigated site all three fertilizer N sources performed similar. At all three sites, highest NUE was achieved with highNRG-N.The differences were significant at both dryland sites, and substantial, but not statistically significant, at the irrigated site. At driland sites, the lowest NUE’s were observed with UAN, and at the irrigated site – with LU. Overall, the results indicated that from the agronomic point of view, highNRG-N has an advantage in terms of protein yield and NUE in spring wheat production in Montana. There were no differences in yield of protein content associated with the ratio of product/water at any of experimental sites. This project will be conducted for one more growing season (2013) at three experimental locations to verify these preliminary findings.