Nitrogen and Phosphorus Requirement of Teff Grown Under Dryland Production Systems of South Central USA.

Nitrogen and Phosphorus are the two major nutrients that limit teff production. The crop is particularly sensitive to N fertilization and both forage and grain yields as well as quality are influenced as a result. We conducted four site-year studies to determine N and P requirement of teff grown under dryland production system. Studies were located in central Oklahoma. Treatments included nine N and P combinations. Commonly grown varieties of teff, Quick-E and Tiffany were used in 2009 and 2010, respectively. Experiments were arranged in Randomized Complete Block Design with three replications. Data were subject to statistical analyses using SAS procedures. Orthogonal Polynomial contrasts and non-linear regressions were used to determine the relationship between N and P with final grain yield of teff. Results showed that for Central Oklahoma N fertilization decision should be based on soil test for N and P. Biological and economic optimum fertilizer N rate was 67 kg ha^-1 which corresponds with a 1.2 t ha^-1 yield goal. Based on soil N, it would be better to top-dress N instead of applying all N at planting. Phosphorus should be applied based on soil test index and percent sufficiency. The existing recommendation developed for weeping love-grass can be used for teff. The crop is sensitive to lodging, and fertilization is at the center of all crop management practices for minimizing lodging. If conditions are ideal for multiple cut, N fertilizer must be applied following the start of regrowth.