File:The quadratic yield response of crops to TRIA in the field.png

The quadratic yield response of crops to TRIA in the field. Potatoes were grown at Stan­ ton, Mich. Each observation is mean of 6 rep­ licates. The control yielded 32.4 MT/ha. Each mean of maize grown at Clarksville, Mich., consists of 6 replicates of 3 times of application and 3 rates of supplemental phosphorus. The controls yielded 10.4 MT/ha. The Iowa maize was grown at Ames and each observation is mean of 6 replicates of 2 cultivars and 2 times of application. The controls yielded 8.5 MT/ ha. The data for Iowa provided by I.C. An­ derson, Iowa State University, Ames. The F value for quadratic trend of yield with rate of application was significant at the 5% level for all tests.