UNL Releases CornWater Irrigation Management Tool

UNL Releases CornWater Irrigation Management Tool

CornWater Welcome Screen Shot

Figure 1: Home page of the UNL CornWater program (figures link to larger versions)

CornWater Screen shot

Figure 2: CornWater evaluations for an example rainfed corn field in Lincoln of crop development stage (R3, Milk and R4, Dough below the time scale marks), amount of available soil water of the first and second foot (lines in cyan and brown), and the depth below the second foot (line in black), and crop water stress (line in red) scaling from 0 (no stress) to 1 (severe stress). The recommendation for irrigation is shown at the top of the screen. Also reported is the total rainfall since planting and total irrigation amount.

CornWater screen shot

Fig. 3: CornWater evaluations for an example irrigated corn field in North Platte. See Figure 2 caption for detailed explanations. Irrigation is not recommended for this field at this moment because no water stress is predicted for now and the next three days. An irrigation event on 7/26 is shown on the graph.

CornWater Screen Shot

Figure 4: List of all fields in an example account.

An Online Real-Time Tool to Help Determine When to Irrigate a Corn Field

August 6, 2014
UNL researchers and educators are pleased to announce the release of the testing version of the CornWater program (Figure 1). CornWater is an online, real-time decision support tool to help irrigators determine when to irrigate corn fields in Nebraska. To make irrigation recommendations, CornWater evaluates, in the real-time mode, available soil water at different soil depths and possible corn water stress based on up-to-date weather data, user-input crop information (including date of planting, hybrid maturity, plant population), and basic soil properties (including soil texture, soil water status at planting time, soil rooting depth, and soil surface residue coverage rate) (Figures 2 and 3).

The recommendation for irrigation is based on crop water stress for a specific field: irrigation is recommended if crop water stress is predicted to occur now or within the next three days and no significant rainfall is expected soon (Figure 2), whereas no irrigation is recommended if no crop water stress is predicted for now and the next three days (Figure 3). In the background, CornWater uses the Hybrid-Maize simulation model (http://hybridmaize.unl.edu/) to accomplish the following tasks for a specific corn field:

  1. Simulate corn growth and development and report crop stage of the past seven days and the next three days.
  2. Estimate the amount of available soil water at different soil depths, including the first foot, the second foot, and below the second foot down to the maximum rooting depth.
  3. Predict crop water stress and recommend irrigation if the crop is under water stress now or in the next three days and no rainfall is expected.
  4. Report rainfall and irrigation events for the past seven days.
  5. Report up-to-date total rainfall since planting and total irrigation amount

The real-time weather data comes from the weather station that is nearest to the specific field and is provided by the High Plains Regional Climate Center (http://www.hprcc.unl.edu/). The program shows simulation results for the past seven days and the next three days. The predictions for the next three days are based on the average weather conditions of the past three days. The output graph also shows rainfall and irrigation events of the past seven days (Figure 3), while the total rainfall amount since planting and the irrigation amount are reported below the graph (Figures 2 and 3).

Note that the CornWater program is released for testing at this stage. The CornWater simulation and prediction are based on the assumptions that the crop is well managed for nutrients, weeds, pests, and diseases and there is no crop damage from hail or other extreme weather conditions.

Irrigators should exercise caution and combine the recommendations from the CornWater program with their current irrigation management practices when making decision for irrigation. Irrigators should also take caution when first starting to use this program because of the three-day prediction window; if well capacity or other factors can limit irrigation applications, there may be a need to start applying water to maintain maximum yield potential prior to the time that CornWater shows water stress coming.

To use the CornWater program, a user must register (for free) for an account at the program website (http://hprcc3.unl.edu/cornsoywater/cornwater/). The user can then add their fields to the program (Figure 4). Note that a field will not be added to a user's account if the program can't find a weather station within 20 miles of the field.

The UNL core team developing CornWater is led by Haishun Yang (Crop Modeler, Department of Agronomy and Horticulture) and includes Chengchou Han (PhD student, Department of Agronomy and Horticulture), William Sorensen (Senior Programmer Analyst, School of Natural Resources), Stonie Cooper (Climate Center Systems Manager, School of Natural Resources), and Dharmic Payyala (graduate assistant, Department of Computer Science and Engineering). The project team also includes UNL faculty, staff and extension educators, including Jenny Rees, Greg Kruger, Martha Shulski, Ken Hubbard, Derek Heeren, Suat Irmak, Gary Zoubek, Patricio Grassini, Ken Cassman, and Jim Specht. The project is supported by funding from Nebraska Corn Board, Nebraska Soybean Board, and Nebraska Center for Energy Sciences Research under the program of Water, Energy and Agriculture Initiative (WEAI) – Phase 2.

Haishun Yang, Crop Simulation Modeler, UNL Department of Agronomy and Horticulture, 
Chengchou Han, PhD student, UNL Department of Agronomy and Horticulture
Jenny Rees, UNL Extension Educator
Greg Kruger, Extension Crops Specialist, UNL Department of Agronomy and Horticulture