Effect of Nitrogen Fertilization Practices on Wheat Yield and Protein in the San Joaquin Valley, California.

Growers seek both high yield and high protein content to improve the profitability of wheat production.  This can be difficult to achieve especially with many of the newer higher yielding wheat varieties.  University of California studies in the 1980’s demonstrated late-season N applications conducted in the San Joaquin Valley increased grain protein content by 0.5 to 2 percent depending on rate and timing. This work was done with Yecora Rojo (already a high nitrogen accumulating wheat variety). Research is needed to evaluate the effectiveness of this practice on a range of newer varieties to quantify the level nitrogen and proper timing needed to achieve both high protein and yields.  Varieties representing a range of yield and protein potential were evaluated for yield, bushel weight and protein content15 nitrogen treatment regimens.   Highest rates gave the greatest response to yield and protein applied at four application timing. Precise timing for protein was not critical (boot vs. protein).