EFFECT OF NITROGEN AND NITROGEN PLACEMENT ON NO-TILL SMALL GRAINS - PLANT NITROGEN RELATIONSHIPS

Relationships between N fertilizer and soil tests on plant N uptake and content and grain protein are important for predicting crop quality and the efficiency of applied N. The objective was to quantify the effect of N soil tests, N fertilizer and placement on N uptake, N content and grain protein of small grains under no-till conditions. Data for multiple regression analysis were collected from no-till, winter and spring wheat and spring barley N fertilizer experiments conducted in northcentral and central Montana, 1986-1991. Dependent variables were regressed against the independent variables of organic matter, nitrate-N, fertilizer-N, grain yield, and interactions between nitrate-N, fertilizer-N and organic matter in both linear and quadratic models. Highly significant equations for most measured plant N characteristics and dependent variables were computed. Nitrate and fertilizer-N were significant independent variables in all equations. Organic matter was added for predicting protein in barley, and the N rate x nitrate-N interaction, and grain yield was added to spring wheat and barley protein equations. There was no difference between N applied below the seed or on the surface with any of the dependent variables.