In April 2025, we launched the first version of our mobile irrigation management app, PLAN. At the time of release, we promised that an irrigation scheduling tool would be made available, specifically designed for producers who don't have access to soil moisture probes. We're thrilled to announce that this scheduling feature is now live and ready for use by all Nebraska producers. This CropWatch article provides a comprehensive, step-by-step guide to help you navigate this new tool within the app.

Brief Introduction: How It Works

This scheduler operates on a water balance model — imagine your soil as a bucket that expands as your crop grows. To prevent water stress, the tool maintains soil moisture depletion at no more than 40-50% of the bucket's capacity. The system estimates root development (which determines your soil "bucket" size) and calculates crop water use by determining crop coefficients based on days after planting (DAP) and reference evapotranspiration data from the nearest Nebraska Mesonet weather stations. The tool requires two key inputs: irrigation applications, which you'll need to enter manually as they occur; and rainfall data, which is automatically retrieved from nearby Mesonet weather stations. 

For producers in the Panhandle area who are already using the weekly crop water use information published by Gary et al., the key advantage of this scheduler is its ability to track daily crop water use specific to your field location, providing more precise and timely irrigation guidance.

How To Use It

Step 1: Download the app in iOS or Android app store. Please note that the app name has changed from PLAN to ACREE (Applied Collaborative Research, Extension and Education). 

Step 2: IMPORTANT — Register your account within the app, then email Dr. Xin Qiao with the field name and location you'd like to use with the scheduler. Currently, field setup must be completed manually through this process, though we plan to add in-app field configuration in future updates.

Step 3: 

1. Once your account is set up and your field has been configured, you should see your field listed on the homepage (Figure 3a).
2. IMPORTANT: Navigate to the "Scheduling" tab, where you'll see a calendar but no graph initially (Figure 3b). Click "Set Planting Date," then enter both the crop type and planting date, and click Save (Figure 3c). While you can add additional information, the crop type and planting date are the minimum requirements for the scheduler to function. Currently, the supported crops are corn, dry beans and sugarbeets. Additional crops may be added in future updates based on user demand.

Step 4: Understanding the Soil Water Depletion Chart

Figure 4 displays the root zone depletion chart, which contains three key lines:

• Blue line: Total available water (TAW) in inches, representing your total "bucket" size. This line grows as roots develop and plateaus when roots reach maximum depth.
• Red line: Maximum allowable depletion (MAD), indicating the threshold to avoid water stress.
• Black line: Actual soil water depletion, showing daily crop water use.

How the system works: The black line moves downward each day as crops use water, while irrigation or rainfall events recharge the soil and move the line upward. When the black line reaches zero, your soil is fully recharged and at field capacity.

Data inputs: The app automatically retrieves rainfall information from Mesonet weather stations, but you must manually enter irrigation amounts.

Adding an Irrigation Event

1. Click on the desired date
2. Click the "+" sign beside that date
3. Enter the irrigation amount
4. Click anywhere on a blank area of the screen
5. Click "Save"

Once entered, a water icon will appear on that date. For example, Figure 4 shows 0.75 inches added to the Demo field on July 31, 2025 for dry beans.

Fine-Tuning the Irrigation Scheduler

The app includes customizable settings that allow you to adjust the scheduler for your specific field conditions:

• Field capacity: Default is set to 1.8 inches per foot, but you can adjust this value based on your soil type.
• Maximum root zone depth: Customize based on your crop and soil conditions.
• Days to reach maximum root zone depth: Set the timeline for full root development.
• Irrigation application efficiency: Default is 85% for center pivot systems, meaning that for every inch applied, 0.85 inches infiltrates into the soil.

These settings can be modified to better reflect your field's unique characteristics and irrigation system performance.

Important Disclaimer

Please note that this scheduler provides estimates of crop water use at your field location and may not always be completely accurate. For example, if your field is located 20 miles from the nearest weather station, rainfall measurements may not accurately reflect conditions at your specific location. 

As we continue to improve the app, we welcome your feedback. Please don't hesitate to contact us with any questions or comments about your experience using the scheduler.

Acknowledgement

We gratefully acknowledge the Nebraska Mesonet for providing essential weather data and ongoing support. We also thank our funding partners, including the Nebraska Dry Bean Commission and the National Science Foundation (Award Number 2420405), for their generous support that made this project possible.