Response Surface Analysis of the Effect of AVAIL and NutriSphere-N On Wheat Production In Montana.

NutriSphere-N (N-N) and AVAIL are enhanced efficiency products currently being marketed for nitrogen (N) and phosphate (P₂O₅) fertilizers, respectively.  A factorial study (3 N rates with and without N-N and 3 P₂O₅ rates with and without AVAIL and the combination of N-N and AVAIL) was conducted on Hard Red Winter Wheat and Irrigated Spring Wheat for 2 years (total 4 site years).  The data was initially analyzed using LSD and orthogonal contrasts.  An LSD is not an appropriate statistical analysis for a study where treatments are related by rate or time.  Orthogonal comparisons failed to take into account the complexity of the experimental design.  Re-analysis of the data using Surface Response Analysis identified that N-N and AVIAIL did improve the efficiency of applied N and P₂O₅ fertilizer applications.  Nitrogen being the most limiting nutrient resulted in a significant N by N-N interaction.  Wheat protein concentration and N removal was also improved with NutriSphere-N.  Incorrect statistical analysis of data is a hindrance in moving new technologies forward that can improve the efficiency of fertilizer applications.