Use of narrow rows in sprinkler-irrigated corn systems to increase grain yields, aboveground biomass, and water and nitrogen use efficiencies

Authors: Delgado, Jorge; Floyd, Bradley; Brandt, Amber; D Adamo, Robert

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2021
Publication Date: 12/30/2021
Citation: Delgado, J.A., Floyd, B.A., Brandt, A.D., D'Adamo, R.E. 2021. Use of narrow rows in sprinkler-irrigated corn systems to increase grain yields, aboveground biomass, and water and nitrogen use efficiencies. Agronomy. 12(1). Article e82. https://doi.org/10.3390/agronomy12010082.
DOI: https://doi.org/10.3390/agronomy12010082

Interpretive Summary: It has previously been reported in the scientific literature (in a 2006 paper by Chad D. Lee) that narrowing the spacing of corn rows usually does not contribute to higher yields in areas south of 43° N latitude in the United States. In contrast with this rule of thumb, our studies with a sprinkler-irrigated corn system in Colorado (2018 to 2020) found increased total biomass production at physiological maturity and/or higher dry grain yields at harvest with the use of narrow rows. The total biomass and/or grain yield did not decrease in any of our 2018-2020 studies. Our results support the hypothesis that the total biomass at physiological maturity and/or harvested grain yields of sprinkler-irrigated corn can be increased by using narrow (15-inch) row spacing rather than standard (30-inch) row spacing. The corn's total biomass at physiological maturity increased by 35.7% and its harvested grain increased by 9.8%. Since corn could be harvested for silage until just prior to physiological maturity, we propose that the increases in total biomass production at physiological maturity suggest higher corn silage production can be achieved with the use of sprinkler-irrigated narrow rows. Our findings using narrow rows in sprinkler-irrigated systems in Colorado are supported by two studies that were conducted by other researchers in Nebraska (from 1996 to 1998) and the Atlantic Coastal Plain (in the 1980s) examining the use of narrow rows in irrigated systems. Our work in Colorado suggests that narrow rows are a potential best management practice to increase yields, economic returns for farmers growing silage and/or grain corn, and efficiency in the use of water and nitrogen applied to sprinkler-irrigated systems of the western United States.

Technical Abstract: We conducted studies from 2018 to 2020 about the potential use of narrow rows and nitrogen fertilizer to increase yields and nitrogen and water use efficiencies in a Fort Collins clay loam soil at the Colorado State University Agricultural Research, Development and Education Center (ARDEC) near Fort Collins, Colorado. Precipitation was monitored at a weather station near the plots and irrigation was applied with a lateral move sprinkler irrigation system. In every study, grain production and/or total biomass was increased by narrow rows and nitrogen fertilization. Narrow rows increased total biomass production in three of the four studies at physiological maturity (R6). Grain at the R6 stage also increased in three of the studies. Harvested grain increased in two of the studies. All studies increased yields and/or total aboveground production, increasing water and nitrogen use efficiencies. Narrow rows (35.1 cm spacing) had 88.1% higher planting density in 2019 and 2020 than the standard rows (76.2-cm spacing) and had 35.7% higher total biomass at physiological maturity and 9.8% higher harvested grain from 2018 to 2020. Since corn for silage could be harvested until just prior to R6 (black layer), we propose that the increases in total biomass production at R6 suggest higher silage production with narrow rows. These studies suggest that narrow rows are a potential best management practice to increase yields, economic returns for farmers growing silage and/or grain corn, and efficiency of water and nitrogen inputs in sprinkler-irrigated systems. We propose increased plant biomass could potentially increase carbon sequestration.