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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #309724
Title: Agronomic factors affecting dryland grain sorghum maturity and production in northeast Colorado

Author
item SAUER, SALLY - Colorad0 State University
item JOHNSON, JERRY - Colorad0 State University
item McMaster, Gregory
item Vigil, Merle

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2014
Publication Date: 9/10/2014
Citation: Sauer, S., Johnson, J., McMaster, G.S., Vigil, M.F. 2014. Agronomic factors affecting dryland grain sorghum maturity and production in northeast Colorado. Agronomy Journal. 106(6):2001-2012.

Interpretive Summary: Grain sorghum is an important dryland crop in southeast Colorado, but expansion into northeast Colorado has been limited by the shorter growing season in the northern part of the State. Our objective here was to examine factors affecting successful sorghum production that might enhance the crops success in northeast Colorado. In a 2-year study at Akron (2010, 2011), Fort Collins (2011), and Stratton (2010) Colorado we investigated row orientation, seeding rate, and row spacing effects for three hybrids within early to medium-early maturity classes on the time to physiological maturity and grain yield. All treatments reached physiological maturity in the four trial environments. Hybrid and seeding rate significantly impacted the amount of heat units (growing degree days or thermal time) required to reach physiological maturity. The medium-early hybrid matured significantly later than the early maturity hybrids. The seeding rate of 20 seeds m-2 matured significantly earlier than 11 seeds m-2, which matured much earlier than 3 seeds m-2. Row orientation did not influence maturity and row spacing was inconsistent in how it affected maturity. Yields were generally acceptable across all environments, hybrids, and agronomic treatments, and ranged from 1690 kg ha-1 to 4845 kg ha-1. Probabilities of the early hybrids reaching maturity were high at Akron and Stratton (at least 62% and 86%, respectively, for the latest simulated planting date), but low for Fort Collins (highest of 75% for the earliest simulated planting date). Grain sorghum can successfully be grown in northeast Colorado, especially if planting early maturity hybrids using 0.76 m row spacing at a seeding rate close to 11 seeds m-2.

Technical Abstract: Grain sorghum [Sorghum bicolor (L.) Moench] is an important dryland crop in southeast Colorado, but expansion into northeast Colorado is thought to be limited due to the shorter growing season. The study examined whether sorghum production could be expanded into northeast Colorado. A 2-year study in northeast Colorado at Akron (2010, 2011), Fort Collins (2011), and Stratton (2010) investigated row orientation, seeding rate, and row spacing effects for three hybrids within early to medium-early maturity classes on the time to physiological maturity and grain yield. All treatments reached physiological maturity in the four trial environments. Hybrid selection and seeding rate significantly impacted the thermal time to reach physiological maturity. The medium-early hybrid (5745) matured significantly later than the early maturity hybrids (88P68 and DKS29-28). The seeding rate of 20 seeds m-2 matured significantly earlier than 11 seeds m-2, which matured much earlier than 3 seeds m-2. Row orientation and row spacing did not influence maturity. Yields were generally acceptable across all environments, hybrids, and agronomic treatments, and ranged from 1690 kg ha-1 to 4845 kg ha-1. Probabilities of the early hybrids reaching maturity were high at Akron and Stratton (at least 62% and 86%, respectively, for the latest simulated planting date), but low for Fort Collins (highest of 75% for the earliest simulated planting date). Grain sorghum can successfully be grown in northeast Colorado, especially if planting early maturity hybrids using 0.76 m row spacing at a seeding rate close to 11 seeds m-2.