Economic Optimum Plant Density for Maize Under Irrigation in Texas.

Economic optimum plant density estimates for maize under irrigation are projected for each of three major soil temperature regimes of Texas: mesic; thermic; and hyperthermic. Maize hybrid entries selected for their average or above average historical performance were evaluated at five locations on cropping conditions representative of three maize production zones. The model development process was implemented in five steps: Step 1. performed analysis of variance to evaluate overall results of trials; Step 2. calculated maximum yield response to increasing plant density for each hybrid entry by site and year; Step 3. determined economic optimum plant densities for each hybrid entry by site and year; Step 4. developed economic optimum response models for each of the nine economic scenarios and three regions (27 regression models); and Step 5. created MS Excel-based utility for calculating economic optimum plant density (EOPD) by region, where user inputs include projected grain value, seed costs and grain yield goal. Analytical results, model development process, and model interface are presented.