101215 Irrigation Scheduling Strategies for Limited Irrigation Conditions.

Poster Number 322-522

See more from this Division: ASA Section: Climatology and Modeling
See more from this Session: Evapotranspiration Measurements and Modeling Poster (includes student competition)

Tuesday, November 8, 2016
Phoenix Convention Center North, Exhibit Hall CDE

Allan A. Andales, 1170 Campus Delivery, Colorado State University, Fort Collins, CO, Jose Luis Chavez, Civil and Environmental Engineering, Colorado State University, Fort Collins, CO and Neil C. Hansen, 701 East University Parkway Drive, Brigham Young University, Provo, UT
Poster Presentation
  • Andales et al 2016 DroughtCIG poster.pdf (1.6 MB)
  • Abstract:
    When precipitation and irrigation water cannot meet seasonal crop water requirements, the amount and timing of irrigations become critical decision factors for managing crop water stress and optimizing corn (Zea mays, L.) production. The objective of this study was to evaluate the performance of the soil water stress coefficient (Ks) and crop water stress index (CWSI) techniques for estimating actual corn evapotranspiration (ETa) for irrigation scheduling under water stressed conditions. Non-stressed crop ET (ETc) was estimated using Penman-Monteith reference evapotranspiration (ETr) multiplied by a non-stressed crop coefficient (Kc). The two aforementioned indices were used to adjust the non-stressed ETc for estimating stressed corn ETa. A field experiment in northeast Colorado considered 3 sprinkler irrigation treatments [opportunity: irrigations occurred according to system capacity; limited: no irrigations during V5 – V10 corn vegetative phases; and drought: 50% of opportunity treatment] and 4 corn varieties, with one being a drought-tolerant hybrid. There were four replications of each treatment combination. Preliminary analyses showed that the Ks tended to over-estimate the level of crop stress, which resulted in under-estimation of ETa and irrigation water requirements. The CWSI seemed to better represent the water stress levels of the corn crop, but field methods for regularly obtaining crop canopy temperature still needs to be refined for tactical (day-to-day) irrigation scheduling. An improved stress coefficient for use under limited irrigation conditions can help provide better ETa estimates for irrigation scheduling.

    See more from this Division: ASA Section: Climatology and Modeling
    See more from this Session: Evapotranspiration Measurements and Modeling Poster (includes student competition)