Improving water and nitrogen use efficiency using soil moisture monitoring to improve irrigation management

2014 Annual Report for LNE12-314

Project Type: Research and Education
Funds awarded in 2012: $210,666.00
Projected End Date: 12/31/2015
Region: Northeast
State: Delaware
Project Leader:
James Adkins
University of Delaware

Improving water and nitrogen use efficiency using soil moisture monitoring to improve irrigation management

Summary

Recent advances in soil moisture monitoring equipment have made it economically feasible for irrigated grain producers to utilize this technology to improve yields and utilize water more efficiently. Nineteen irrigated corn farmers expressed interest in evaluating remotely read, soil moisture monitoring equipment for the 2014 season. Each farmer was surveyed in person prior to the growing season to determine their individual growing/irrigation practices and historical yields, water and nitrogen use.

A Watermark 950T/R wireless soil moisture system was installed in each of 19 cooperator fields in late May and early June. A 20th system was planned but the failure of the modem just prior to startup and the subsequent 5 week delay for repairs made installation unpractical. One on one trainings were conducted to familiarize the farmers with the web based reporting service and how to interpret the data gleaned. The equipment was maintained by University of Delaware personnel who also kept in weekly contact with the cooperators to ensure that they could access and understand the soil moisture readings. 2014 proved to be an ideal growing season in Delaware with timely and adequate rainfall and low heat stress levels. In many cases dryland corn yields were on par with typical irrigated yields, thus minimizing the importance of irrigation for the 2014 season. The sensors were removed just prior to harvest and each cooperator was interviewed individually to determine the successes and failures of the equipment, data interpretation, ease of implementation into the irrigation schedule and overall usefulness of the project.

Of the 19 cooperator representing 8,940 irrigated acres, only 3 responded in post season survey that they planned to purchase soil moisture equipment. Another 7 responded that they were researching the costs of utilizing soil moisture equipment versus current commodity prices and might purchase equipment in the future.

Objectives/Performance Targets

1. Twenty irrigated corn and soybean producers will be selected by the project team for the demonstration of the field monitoring equipment. (May 2014)
1. Milestone achieved April 2014.
2. Each cooperator will be trained on a one on one basis to access their soil moisture status via the internet, analyze the data and modify their irrigation schedule to address crop needs. Growers will become proficient in interpreting soil moisture data into irrigation recommendations through frequent communication with the research team in the form of site visits, phone, and email contact. (May – Aug 2014)
1. Milestone achieved April – September 2014
3. Four Hundred growers will receive invitations to attend irrigation workshops at Delaware Ag Week. (November 2014)
1. Over six hundred invitations to attend the irrigation session at Delaware Ag Week were sent the week of December 8, 2014
4. Two hundred and fifty producers with center pivot irrigation will attend irrigation management workshops that discuss the findings of the 2014 field research/demonstration. (December 2014 – January 2015)
1. The Irrigation Session at Delaware Ag Week is scheduled for January 15th, 2015 where the results from the 2013 and 2014 season will be presented. Typical attendance for this session is 250-450 farmers.
5. Twenty new producers will be selected by the project team for the demonstration of the field monitoring equipment based on interest they expressed at the winter meetings. (May 2015)
1. In progress.
6. Four Hundred growers will receive invitations to attend irrigation workshops at Delaware Ag Week. (November 2015)
7. Two hundred producers per year with center pivot irrigation will attend irrigation management workshops that discuss the findings of the 2013, 2014 & 2015 field research. (December 2015 – January 2016)
8. Forty-five growers representing nine thousand acres will adopt soil moisture monitoring to manage irrigation. (2015 growing season)
Thirty-four irrigators representing sixty nine hundred acres will improve their irrigation scheduling on 6,900 acres of corn to improve yields by 15 bu/acre ($621,000/year) and increase nitrogen use efficiency from 1 lb applied per harvested bushel to 0.95 lbs/bu. An additional 14 irrigators will improve soybean irrigation on 2800 acres by 5 bu/acre ($182,000 per year)
• In 2014, 19 irrigators representing 8,940 irrigated corn acres have participated in this project, with only 2 reporting an increase in yield as a result of participating. Most growers indicated that the high dryland and irrigated yields for this season were primarily the result of mild temperatures and timely rainfall.
Twelve of these thirty four irrigators will reduce their overall irrigation application by two inches per year over twenty-five hundred acres, resulting in a five percent increase in yield (approximately $110,000/year), $20 per acre reduction in pumping costs ($50,000/year) and 135 million gallons in conserved water.
• Only 2 cooperators indicated that they used less water using the sensor data. 5 cooperators said they used more water and 5 more stated they used the same amount. The other 7 participants didn’t look at the data, didn’t trust the data or couldn’t figure out how to access the website.

Accomplishments/Milestones

Much like 2013, there was overwhelming interest in participating in this project, especially from corn producers. Most of the previous year’s cooperators requested to be involved for a 2nd year as the extremely wet 2013 season virtually eliminated any opportunity to access the value of soil moisture sensing. The initial grower interviews went smoothly and the farmer’s goals were in line with the goals of the project.

The soil moisture equipment installation went as planned, and 4 monitoring stations were installed in each field with one station in both the lightest/highest soil and the heaviest/lowest soil and 2 stations in the most predominate soil type. Each station monitored soil moisture levels at 6”, 12” and 18” below the soil surface and wirelessly transmitted the data back to a central data logging receiver approximately 10 to 15 times per day. The combined data from each of the 4 stations could be viewed real time by each cooperator on the internet.

While the equipment failure rate was extremely high in 2013 only 1 major equipment failure happened this season. One of the base modems failed and could not be repaired before the primary irrigation season had passed. The data from one field showed extremely dry soil moisture levels despite field visits showing adequate moisture. This location had a tight soil with considerable gravel, clay and silt and in hindsight required a different sensor installation method to ensure good soil contact.

Unfortunately, during the driest and most critical crop stage for corn (July 4th weekend), the reporting website was down and no one was able to access the data for 4 days. The website issues were easy to repair, but all of the employees at the hosting site were off for the holiday and unaware of the issue.  6 cooperators reported that they looked at the data every day and another 2 stated every other day. 5 growers looked at the data once per week and the remaining 6 either did not look at the data at all or had connection/equipment problems.

The equipment was removed in early September, just prior to harvest and the post season surveys of each cooperator were conducted. Several growers expressed their opinion that the sensors provided more value for determining when to start irrigating after a major rain event than for daily management.

Impacts and Contributions/Outcomes

In the post season survey, 3 of the 19 cooperators responded that they plan to purchase soil moisture equipment to help them manage their irrigation in the 2015 season. Another 7 responded that they might purchase the equipment if it is affordable and reliable. 8 farmers answered that they would not consider purchasing any soil moisture equipment.

While all 19 of the participating farmers saw increased yields, 15 of those attributed the yield increase to weather. Only 4 responded that improved management and cooperation with UD played a role in the yield increases. 8 farmers responded that they plan to make changes to their irrigation schedule as a result of this project. Overall, when asked what could be done to improve this project 8 participants responded with “nothing”; 4 answered “keep the equipment working or find better equipment”, and 4 replied “setting up the web service/ assemble a quick start guide” (it should be noted that we gave each cooperator a guide but many never read it).

The overall feeling of the 2014 cooperators was that they felt that the soil moisture monitoring added value to their operation and made the irrigation decisions less guesswork and more science based. Everyone had major concerns about the reliability, longevity and cost of the equipment. Most felt that the biggest hurdle to using soil moisture equipment is the 8 – 12 man hours required to install and setup the network during an already high work load period. One farmer commented that he thought the soil moisture monitoring should be a service provided by the University.

Collaborators:

Dr. Cory Whaley

whaley@udel.edu
Sussex County Extension Agent
University of Delaware
16483 County Seat Hwy
Georgetown, DE 19947
Office Phone: 3028567303
Scott Wright

sewright@udel.edu
Irrigation Research Techician
16483 County Seat Hwy
Georgetown, DE 19947
Office Phone: 3028567303
Phillip Sylvester

phillip@udel.edu
Kent County Extension Agent
University of Delaware
16483 County Seat Hwy
Georgetown, DE 19947
Office Phone: 3028567303