Tule Irrigation Recommendations
author By Tom Shapland, PhD, May 4, 2015

Tule Irrigation Recommendations

We are excited to release our newest feature -- the Tule Irrigation Recommendation! Every irrigation manager must answer two questions: 1) What is the water status of my field? and, 2) What do I do about it? Tule's remote water stress monitoring (the Plant Response Index, or PRI) and the Tule Target PRI help you answer the first question. The Tule Irrigation Recommendation helps you answer the second question. It provides you with an irrigation amount to achieve the Tule Target PRI.

Where can I find the Tule Irrigation Recommendation?

The Tule Irrigation Recommendation is the highlighted column in the first table on the web dashboard. It is the recommended irrigation amount for the upcoming seven days.

Recommendation table

How does it work?

There are three steps to deriving the Tule Irrigation Recommendation for your field. In the first step, we contextualize your field. Second, we evaluate the water status of your field. Finally, we determine an irrigation recommendation.

Step 1: Defining the context for your field

Tule irrigation requirements start with defining the the context of your field.

  • Crop Type and Phenological Stage: Irrigation strategies are dependent on crop type and phenological stages of the plants. Examples include establishment, canopy growth, and ripening.
  • Production Goal: Irrigation is highly dependent on the tradeoffs between yield, desired stress levels, and water availability.
  • Winter Rainfall and Soil Water Holding Capacity: In some regions during the spring, there may have been high enough rainfall and low enough winter ET that water is stored in the soil profile. The stored winter rainfall may delay or reduce irrigation requirements. A weak soil with low water holding capacity cannot store much winter rainfall or applied water.
Step 2. Evaluating the water status of your field

Your field water status is separated into two categories according to its crop type, phenological stage, and production goal: “on track” or “off track”.

For a field with a full canopy, the water status is off track if the PRI has decreased from the Target PRI. If your field is still developing its canopy, its PRI will not have reached the Target PRI yet. In those cases, we compare your PRI to the average PRI from similar fields in the same category. If your field is not progressing towards the target in line with similar fields, then we consider your field off track.

Step 3. Recommending irrigation amounts

The Tule Irrigation Recommendation takes into account the water status of your field, best practices in crop science, and the Tule stress and irrigation data from similar fields.

For a given water status, we examine the academic literature for irrigation requirements and for the impact of various degrees of deficit irrigation. The crop science sometimes is incomplete (i.e., there are no studies that match your recent innovations in management practices) or insufficiently specific for your field context. Therefore, we also take into account what has worked historically for similar fields, and is working currently for similar fields, to maintain or correct the water status of your field.

These factors inform the percent of ET that your field requires to achieve the Tule Target PRI. We apply that percent of ET to the Actual ET from your field over the previous seven days. The percent of ET multiplied about the Actual ET is the Tule Irrigation Recommendation for your field.

The Tule Irrigation Recommendation will be updated daily on our website. The recommendations will change according to your field water status. As we enter different phenological stages and your Target PRI changes, the recommendations will respond accordingly.

The Management of Chaos

As all growers know, irrigation management is complex. Agriculture is the management of heterogeneity -- or, some growers say, the management of chaos. We have built the Tule Irrigation Recommendation to consider a large number of factors. We believe the recommendation will provide helpful context for your irrigation decision. This feature will continue to improve as our system gains more information about your field and fields similar to yours. If our irrigation recommendations do not match your experience, please reach out to us. Your feedback is the best way for us to ensure that the Tule Irrigation Recommendation is as accurate for your field as possible.

We would love to hear from you!

Please be sure to attend the nearest regional Web Dashboard training event coming to your region in the next few weeks. Please check your inboxes the invitation or email us for details. Even if you cannot attend, please feel free to email us at support@tuletechnologies.com. We would love to get your feedback.