Agronomy and Crop Sciences Commons^™

Corn Grain Yield Components And Nutrient Accumulation In Response To Nitrogen, Plant Density And Hybrid, Maria Julia Santoro

Theses and Dissertations--Plant and Soil Sciences

Modern maize hybrids exhibit higher yields, increased biomass production, stress tolerance and greater nitrogen (N) use efficiency. Increased biomass accumulation can influence nutrient uptake and lead to increased nutrient removal. Hybrids were tested at seeding rates (SR) of 74000 (low) and 148000 (supraoptimal) plants ha^-1 and at N rates of 0 (deficient) and 390 (non-limiting) kg N ha^-1. Plants were sampled at V7, V14, R3, R5 and R6 and separated into vegetative and reproductive fractions for determination of dry matter and N accumulation. Grain yield was harvested at R6.

The high SR and high N treatment combination …

Corn (Zea Mays L.) Yield Response To Defoliation At Different Row Widths, Martin Leonardo Battaglia

Theses and Dissertations--Plant and Soil Sciences

Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm …

Hybrid, Row Width, And Plant Population Effect On Corn Yield In Kentucky, Chelsea Clay Mcfarland

Theses and Dissertations--Plant and Soil Sciences

Studies were conducted in 2011 and 2012 to determine if narrow row corn (Zea mays L.) and/or greater plant populations could affect yield, time to silking, and other physiological characteristics. Main plots of six hybrids were arranged as a randomized complete bock design with three replications. Split plots were row widths of 76-cm (wide rows) and 20-cm rows on 76-cm spacing (twin rows). Split-split plots were target plant populations of 75 000 and 111 000 plants ha^-1. Corn was no-till seeded into soybean stubble near Lexington, KY in 2011 and 2012. Year interacted with most factors analyzed …