Cotton Incorporated and the USDA have combined to study a high tech, real time system of monitoring soil moisture that will provide much more accurate production information for official variety testing programs around the country — and it could provide valuable data for growers further down the road.

USDA Researcher Phil Bauer in South Carolina says the concept for cotton researchers is to put a system of soil moisture sensors, like those used by California-based PureSense Solutions, in variety tests to develop an index.

For every trial there will be an index number that characterizes the soil water conditions that occurred during that trial.

“In a droughty year, for example, we can determine which variety did the best, and which others didn’t perform so well under drought stress,” Bauer says. “Right now, a grower can look at the mean yield and say, it’s a dry year and the variety may not do so well under more normal conditions. With the index, he can determine how a variety performs across a wide range of weather variables.”

Using the PureSense system, researchers get soil moisture data every 20 to 30 minutes.

“By looking at the data at the end of the season during specific growth stages, we will know during squaring the variety did this, and when the plant flowered, the variety did this,” Bauer says. “It gives us nearly real-time information on how plant water uptake in the soil is progressing through the growing season.”

The USDA and Cotton Incorporated researchers hope to establish an index rating for every Official Variety Testing program at each Land Grant university in every state. Using these index numbers, growers can more accurately select varieties for top production, based on their production practices, soil type, etc.

As seed companies push to provide new and improved varieties to growers on a more timely basis, having day-to-day data on which to base release of one variety, in a particular part of the country, versus another variety could be a major breakthrough in seed technology.

Getting new varieties quickly

Programs like Monsanto’s Deltapine New Product Evaluators have had much success in testing new cotton varieties with growers and getting top-producing varieties quickly into the marketplace.

With real time data to support their system of 200 or so growers, testing 20-acre fields, the company could be much more precise in selecting varieties for particular areas of the country.

The struggle with water management that has been ongoing in the Southwest and Midwest regions of the country for many years is almost sure to move into other production areas, including the Southeast. Precise management of water resources is a more long-term goal of the South Carolina test, Bauer says.

“We hope to develop these sensors to help growers better manage irrigation. The practical application of this technology is far-ranging. The current system requires a lot of user inputs, but it’s manageable.”

Pointing to a field of cotton at the Pee Dee Research Center, Bauer says, “We could pull this field up on a computer screen, and if the color is blue, it doesn’t need water; if it’s yellow, get ready to water; and if it’s red water now — no matter what the weather forecast says.”

The test site in Florence, S.C., is part of a nationwide study being conducted by Cotton Incorporated and various research partners.

Sensors in the South Carolina study are sending back information from 3, 6, 12 and 24-inch depths every 20 to 30 minutes. Using cell phone technology, each probe radios data from four sensors through a central system, which calls it in every 20 to 30 minutes.

The company has offices in foreign countries, so during nighttime hours in the U.S. they can analyze data and report back, if they find sensors not working or any abnormality in the programs.

This year cotton growers in the Southeast have struggled to manage target spot or corynespora leaf spot, and each year different diseases, insects and weeds challenge cotton yield and quality potential.

However, one of the most continuous challenges to cotton production is sustaining proper moisture for a particular cultivar.

The series of tests, using the PureSense system like the one in Florence, S.C., includes projects in Lubbock, Texas; Marianna, Ark.; and Maricopa, Ariz.

Including the PureSense sensors occurred this year, says Ed Barnes, director of agricultural and environmental research at Cotton Incorporated.

Evaluating several systems

“We were in the process of evaluating a number of systems from previous studies when we learned about PureSense solutions. Their system showed great promise and we incorporated it into our study,” Barnes says.

To date, the study is proceeding very well, he says. This year, the primary focus is on identifying a remote monitoring and decision-support system that will be economical and efficient for cotton producers nationwide.

Once the right system has been identified, project investigators will work to create a viable stress index that can be used to distinguish various drought-tolerant cotton cultivars in order to effectively identify which varieties will provide the highest yields under water stress conditions.

Speaking at a recent field day at the Pee Dee Station in South Carolina, Barnes said, “Cotton producers know water is a very precious and expensive resource.

“Studies have shown that every inch of irrigation a producer is short can reduce yield as much as 70 pounds per acre. In the past, we’ve undervalued the importance of precise irrigation scheduling.”

Cotton growers can use many different types of systems to monitor soil moisture and manage irrigation needs. The recurring challenge with many of these systems is the difficulty in understanding the data and putting information to work to produce a better crop.

High tech devices, such as neutron probes, which can be used to determine the amount of hydrogen in the soil or tracking highly complex matrix water potential, can be time-consuming and highly technical, often requiring attention at a time when growers have numerous other projects underway.

Barnes says the soil moisture monitoring system in place across the cotton belt should be ‘grower friendly’ enough for adaptation on the farm at some point in the future. 

First and foremost, the system will allow producers to get the data they need without an engineering degree.

Second, the system integrates data from four widely dispersed sites for more effective analysis.

And third, Barnes says, “The PureSense solution works with an array of sensors, which enabled us to continue using the Decagon EC Series sensors we had been happy with in a previous study.”

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