Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2000
Publication Date: N/A
Technical Abstract: One aspect of precision agriculture is the concept of variable-rate seeding (VRS), adjusting seeding rates to match the productive capacity of the soil. In theory, VRS could maximize crop performance or economic returns by appropriately matching seeding rates to production capacity within fields. The objectives of this project were to determine the optimal plant tdensity for variable-rate corn (Zea mays L.) seeding and to investigate factors that affect optimal plant density. Seven site-years of studies were conducted in 1998 and 1999. Apparent soil electrical conductivity (ECA) data were collected prior to planting. Corn was planted at five rates using a commercially available variable-rate planter. Experimental design was a randomized complete block with planting treatments in strips. Corn was harvested by a combine equipped with a yield monitor and DGPS. A combine mounted stalk sensor measured harvested populations. Coefficients of determination showed that plant populations were affected by soil and environmental conditions as well as seeding rate. Economically optimum plant densities were calculated using yield response data, seed corn costs, and grain prices. Most fields were shown to require a variable plant density to reach maximum yields. Economic returns based on matching optimum populations to soil ECa were only slightly higher than having a uniform at-harvest population.