UNL CropWatch May 28, 2010: Nebraska Agricultural Water Management Demonstration Network (NAWMDN) Up | CropWatch

May 28, 2010

In most of Nebraska producers are finishing up with planting and haven’t started to think about this year’s irrigation. Most of the state has received more rainfall than the corn, soybean, and grain sorghum crops have used at this early growth stage. In most years things will change, but it is great to start out with a full soil profile of water — a little like having money in the bank.

Where’s Your ETgage

Now is the time to get your ETgage out from storage and replace #54 canvas cover and wafers, said Gary Zoubek, extension educator.

You’ll want to then fill the ETgage with distilled water and get it primed. A check list with instructions on using ETgages and Watermark sensors is at http://water.unl.edu/cropswater/nawmdn-publications.

A Cost-Effective Investment

Compared to other expenses involved in agricultural production, this equipment is relatively cheap. An ETgage costs approximately $205, and soil moisture sensors and a hand-held meter or data logger cost $300-$500.

Producers have reported the past two years that these two tools used together can save 2 inches or more of irrigation water per growing season. If a pivot puts on an inch of water per revolution, you could save $2,000 to $3,000. These tools can more than pay for themselves in the first year, Zoubek said.

So, even though we don’t need to think about irrigation management now, it is time to start planning. We now have nearly 500 producers across Nebraska who are involved in the Nebraska Agricultural Water Management Demonstration Network (NAWMDN). This effort began in 2005 with about 18 growers and has continued to grow with participants from across the state.

Two tools have been selected to help growers, crop consultants, and others make better irrigation management decisions.

The first tool is an ET gage® or Atmometer which along with crop growth stage can be used to estimate crop water use or evapotranspiration (ET).

The second is the Watermark soil matric potential sensor which can be used to measure available soil water in the soil profile. The sensors are glued into pvc pipe and, when the crop is small, placed in the crop row in the most representative area of the field. They have typically been installed at depths of 1, 2 and 3 feet. Hand-held meters as well as dataloggers can be used to obtain the readings.

The more information gathered, the more informed decisions that can be made for more effective irrigation management. The goal of the NAWMDN effort is to try and keep as much of the rainfall received on the farmland and to draw down the soil moisture profile, especially at the end of the season so that Mother Nature can refill it.

Many NAWMDN cooperators post the weekly total ETgage readings online. This information can then be used by other producers in the area who are actively engaged in irrigation management. New this year on the website will be the addition of data from several automatic weather stations that will be updated daily.

For more information about the NAWMDN contact one of the many Extension or NRD contacts involved in the effort and listed at http://water.unl.edu/cropswater/contact.

Gary Zoubek
Extension Educator, York County

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