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United States Department of Agriculture

Agricultural Research Service

Research Project: Spatial Modeling of Agricultural Watersheds: Water and Nutrient Management and Targeted Conservation Effects at Field to Watershed Scales

Location: Agricultural Systems Research Unit

Title: When will my wheat plant flower?

Author
item McMaster, Gregory

Submitted to: Colorado State University Technical Report
Publication Type: Experiment Station
Publication Acceptance Date: April 21, 2013
Publication Date: N/A

Interpretive Summary: Knowing when to expect your wheat crop will reach a specific growth stage is important for many reasons. The recommended time for applying herbicides is increasingly being based on the growth stage, or number of leaves that have appeared. The effectiveness of managing practices such as spring application of N fertilizer or limited irrigation strategies can be improved when timed to specific growth stages. However, when winter wheat reaches a growth stage depends on factors such as weather (heat and drought) or variety (early or late maturity). Fortunately, much research has studied the timing for reaching a growth stage as a function of the environment (called phenology), and we can predict wheat growth stages quite accurately. Until recently, most phenological information has been used by scientists and in detailed crop simulation models. To facilitate the accessibility of this information, USDA-ARS has developed a computer program (PhenologyMMS) that is available to farmers and consultants for predicting crop growth stages. This program uses historical weather data for certain locations in eastern Colorado. After setting a few inputs such as planting date for a particular year, it will predict the date of seedling emergence and subsequent growth stages; first tiller appearance, jointing, beginning of booting, heading, flowering, and maturity. The user can run the model under irrigated or dryland conditions. The growth stage predictions can be based on a “generic” winter wheat variety, for early, medium, or late maturing varieties, or for some specific varieties of wheat. The basic science behind PhenologyMMS and how the program can be used is discussed, and analysis of when growth stages can historically be expected to occur for eastern Colorado is provided.

Technical Abstract: Knowing when to expect your wheat crop will reach a specific developmental event is important for many reasons. The window for applying herbicides is increasingly being based on the growth stage, or number of leaves that have appeared. The effectiveness of managing practices such as spring application of N fertilizer or limited irrigation strategies can be improved when timed to specific growth stages. However, when winter wheat reaches a developmental event depends on factors such as weather (heat and drought) or variety (early or late maturity). Fortunately, much research has studied the timing for reaching a developmental event as a function of the environment (called phenology), and we can predict wheat developmental event quite accurately. Until recently, most phenological information has been used by scientists and in detailed crop simulation models. To facilitate the accessibility of this information, USDA-ARS has developed a computer program (PhenologyMMS) that is available to farmers and consultants for predicting crop developmental events. This program uses historical weather data for certain locations in eastern Colorado. After setting a few inputs such as planting date for a particular year, it will predict the date of seedling emergence and subsequent developmental events; first tiller appearance, jointing, beginning of booting, heading, flowering, and maturity. The user can run the model under irrigated or dryland conditions. The phenological predictions can be based on a “generic” winter wheat variety, for early, medium, or late maturing varieties, or for some specific varieties of wheat. The basic science behind PhenologyMMS and how the program can be used is discussed, and analysis of when developmental events can historically be expected to occur for eastern Colorado is provided.

Last Modified: 4/19/2014
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