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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Rangeland Resources & Systems Research » Research » Publications at this Location » Publication #330830
Title: Long-term simulation of growth stage-based irrigation scheduling in maize under various water constraints in Colorado, USA

Author
item FANG, Q - Qingdao Agricultural University
item Ma, Liwang
item Ahuja, Lajpat
item Trout, Thomas
item Malone, Robert - Rob
item Zhang, Huihui

Submitted to: Frontiers of Agricultural Science and Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2016
Publication Date: 2/24/2017
Publication URL: https://handle.nal.usda.gov/10113/6961210
Citation: Fang, Q.X., Ma, L., Ahuja, L.R., Trout, T.J., Malone, R.W., Zhang, H. 2017. Long-term simulation of growth stage-based irrigation scheduling in maize under various water constraints in Colorado, USA. Frontiers of Agricultural Science and Engineering. doi:10.15302/J-FASE-2017139.

Interpretive Summary: With inevitable change in climate condition, farmers are increasingly facing water shortage in the Great Plains of the United States. Optimizing the limited water resources is essential for the future agriculture, especially when there are considerably variations of water supply on a monthly, seasonal and yearly basis. The objective of this study was to optimize irrigation scheduling between the vegetative (V) and reproductive (R) stages of maize under different available water levels in Northeastern Colorado. A calibrated system model for the site was used to create long-term (1992-2013) scenarios to meet 40%, 60%, 80%, and 100% of crop evapotranspiration (ET) requirements at both V and R stages, subject to various seasonal and monthly water availabilities. Simulation results showed that the most reasonable irrigation levels between the V and R stages of maize were identified as 60/100, 80/100, and 100/100 of crop ET requirement for the 30 cm, 40 cm, 50 cm seasonal water available conditions, respectively. When monthly water limit was imposed, the corresponding reasonable irrigation targets between the V and R stages were 60/100, 100/100, and 100/100 of crop ET requirement for 30 cm, 40 cm, and 50 cm seasonal water availabilities, respectively. The results should help farmers to better allocate water resources between the vegetative and reproductive stages for optimum crop yield.

Technical Abstract: Due to the differential crop responses to water stress at different growth stages, scheduling irrigation within a crop season is a challenge facing agricultural producers, especially when water availability varies on a monthly, seasonal and yearly basis. The objective of this study was to optimize irrigation schedules between the vegetative (V) and reproductive (R) stages of maize under different available water levels in Northeastern Colorado. Long-term (1992-2013) simulations with the calibrated Root Zone Water Quality Model (RZWQM2) were designed to meet 40%, 60%, 80%, and 100% of crop evapotranspiration (ET) requirements at the V and R stages, subject to seasonal water availabilities (no water limit, and 50 cm, 40 cm, and 30 cm), with or without monthly limits (totally 113 scenarios). The most reasonable irrigation levels between the V and R stages of maize were identified as 60/100, 80/100, and 100/100 of crop ET requirement for the 30 cm, 40 cm, 50 cm seasonal water available conditions, respectively, based on the simulated high grain yield and water use efficiency from 1992 to 2013. When monthly water limit was imposed, the corresponding reasonable irrigation targets between the V and R stages were 60/100, 100/100, and 100/100 of crop ET requirement for the 30 cm, 40 cm, and 50 cm seasonal water availabilities, respectively. The reasonable irrigation targets that produced higher crop yield with lower annual variations were also discussed for a five-year projected water availability.