Located way in the back of the Tidewater Research Center in Plymouth, N.C., the total ag water management research site continues to provide valuable data since it was established in 1985. 

The site was originally dedicated to drainage related research but has been recently customized to focus on both drainage and irrigation. There is nothing quite like it anywhere in the world, where researchers use the latest technology to evaluate water stress, be it too much water or not enough.

In the total ag water management site, water can be either added or taken away to simulate drought or excess water conditions. It’s an engineering marvel, with state-of-the-art tools that include sensors that monitor the water table in the field to determine whether to remove or add water and infrastructure to control soil water and monitor inputs and outputs from the system.

On Aug. 3, in late afternoon following the Blackland Farm Managers Tour that was held in Pantego earlier in the day, the Tidewater Research Station hosted another field day to showcase the technology. At the field day, Chad Poole, North Carolina State University water resiliency specialist, noted that capital investments in irrigation and drainage infrastructure are two of the most expensive a farmer makes, and it can’t be left to chance.

North Carolina State is committed to the research, along with commodity groups. In the first year of Poole’s total ag water management research project, which is now in its second year, the Corn Growers Association of North Carolina provided financial support. This year, the North Carolina Soybean Producers Association provided financial support as well.

Poole said the goal of the research is to evaluate corn hybrids and soybean varieties under different water stress conditions in a given year to help farmers decide which hybrids or varieties to plant, depending on how they respond to water stress, either drought or excess water.

“We’re learning a lot from this project. We’re learning that hybrids and varieties respond to water differently. They also respond to nutrient uptake very differently,” Poole said at the field day.

He said this is important, particularly in today’s environment of high nitrogen fertilizer prices.

“Last year, with the data at this site that was gathered under wet conditions, we put out the same amount of nitrogen across all treatments. The yield across 15 hybrids ranged about 45-65% higher under well-drained conditions versus wet conditions last year when the same amount of nitrogen was put out. That means you had a 30-40% loss of nitrogen — under wet stressed conditions,” Poole said.

$100 bill

“If you’re not taking care of water management, you might as well reach in your pocket, pull out a $100 bill and throw it away on every acre you farm with corn given nitrogen prices seen in 2022," he said.

Poole said the collaborative approach is key to the project’s success with a number of North Carolina State specialists involved. Precision Ag Specialist Jason Ward is using drone imagery and NDVI (Normalized Difference Vegetation Index) to evaluate the plots. Corn Specialist Ron Heiniger is evaluating corn response in the plots, while Soybean Specialist Rachel Vann is evaluating the soybeans. Soil Fertility Specialist Luke Gatiboni is examining the fertility side.

“Grad students working in collaborative efforts across this project are assessing the stress levels that are out here and working to determine if we can change fertilizer recommendations in-season based on the hybrid response,” Poole said.

Ward said the use of drones and crop reflectance data will help researchers determine which varieties and hybrids are stressed by either drought or excess water. Ward and his team will quantify the stress points to help growers decide which variety or hybrid to plant, depending on their response to the stress.

Jason Ward said the use of drones and crop reflectance such as NDVI (Normalized Difference Vegetation Index) will help researchers determine which varieties and hybrids are stressed by either drought or excess water. (John Hart)

“We are continuing to quantify the stress. We came out here every week between V6 and tassel (in corn) and took some plant tissue samples, flew it and got some UAV data. We are leveraging these technologies to allow the plant to tell us how stressed it is because we think we can make some management decisions, especially if you have water stress early in that plant’s  life. There might be things we need to do differently. We are blessed to have this site that allows us to get this data and drive to some really good conclusions,” Ward said.

Lack of water

Poole said the biggest water management issue in North Carolina this year is lack of water. Most of the state is excessively dry, with the exception of the four counties that make up the Blacklands, which are generally doing fine.

Poole pointed to the North Carolina Environment and  Climate Observing Network (ECONet) that allows North Carolina State to predict evaporative schedules. ECONet consists of 44, 10-meter (33-foot) tall aluminium towers across 34 counties in North Carolina and one county in South Carolina. The ECONet was developed in cooperation with state and federal agencies in order to record weather and climate observations for a variety of applications.

“The North Carolina Corn Growers Association sponsored a project this year to actually put a statewide soil moisture network in for non-irrigated corn. We strategically placed four of these units on research stations across the state directly adjacent to the ECONet sites. We’re trying to gather information from this network that we can use to develop new crop coefficients for each region of North Carolina to improve our irrigation capabilities,” Poole explained.

Poole said farmers can log on to the portal after they get a password from him that allows them to look at the soil moisture status at any of the locations in real time. This will allow them to make irrigation decisions based on what’s occurring in a given area.

“By the end of this grant, we will have 12 of these systems across North Carolina. If you’re interested in this, get in contact with me, I’ll get you hooked up with it. We’re also working with a company to get this data on the North Carolinas State Extension Corn Portal so that information will be available to all agents and all growers across the state,” Poole said.