Corn Hybrid Response to Skip-Row Planting Configurations and Plant Population in Western North Dakota

Management practices are needed for stable com (Zea mays L.) production in drought prone regions of western North Dakota. Analysis of weather data suggests areas like those near Mandan and Hettinger suffer severe drought about 50% of the time. Since most of the rainfall in western North Dakota is in early summer, the soil water reserves may be completely utilized by anthesis, which can result in low yields or crop failure because of corn's water requirement and sensitivity to stress during this period. Skip-row planting configurations can conserve water and improve grain yield in certain environments. The objective of this research was to identify hybrids and hybrid characteristics that are better adapted to skip-row planting configurations and the optimum plant population when rows are skipped. Three field trials were conducted in 2009 and 2010 in western North Dakota. Six hybrids with two populations were used within three planting configurations: plant every row (P All), plant two - skip one row (P2S1), and plant one - skip one row (P1S1). Weather data were also analyzed to determine the frequency of drought. The long-term average precipitation in Mandan is 43.3 cm annually. In 2009 and 2010, there was 48.4 and 48.0 cm of rain, respectively. Grain yields for the three environments analyzed, 2009 dry pea, 2010 dry pea, and 2010 sunflower residue, were 6.93, 6.97, and 6.97 Mg ha^-1, respectively. Planting configuration affected grain yield and plant population at harvest with P All having significantly more grain yield and final plant population than P2S1 and P1S1, which were not significantly different from one another. The P All, P2S1, and PlS1 grain 111 yields were 7.89, 6.78, and 6.27 Mg ha^-1, and the plant populations at harvest were 63,149, 51,608, and 45,622 plants ha^-1, respectively. The plant population partially explains the difference in grain yield for the three planting configurations. The two plant populations used in these experiments were 59,280 (high) and 44,460 (low) plants ha^-1, but at harvest they actually were 57,953 and 48,967 plants ha^-1, respectively. The higher plant population had significantly more grain yield and significantly Jess test weight. The grain yield for the high and low plant populations was 7 .19 and 6. 73 Mg ha^-1. The six hybrids tested were NuTech 3T-484, PH 38R51, NuTech 3C-389, DKC 33-54, DKC 30-23, and PH 39D97, and their grain yields were 7.76, 7.50, 7.07, 6.81, 6.42, and 6.20 Mg ha^-1, respectively. Overall, later maturing hybrids had significantly more grain yield than earlier maturing hybrids due to the optimal growing conditions. The earliest maturing hybrid PH 39D97 had significantly less grain yield than all of the other hybrids tested because it had a significantly lower plant population at harvest. The plant population of the other five hybrids did not differ significantly. In wet years such as 2009 and 2010, highest grain yield is attained by planting all rows with a plant population of 59,280 plants ha^-1 with later maturing hybrids, especially NuTech 31-484.See thesis document for full abstract with properly formatted mathematical symbols