Using Irrigation Management Tools To Save Water And Energy ($20.12 an acre)

Using Irrigation Management Tools To Save Water And Energy ($20.12 an acre)

The Nebraska Agricultural Water Management Demonstration Network (NAWMDN)

January 9, 2009

Suat Irmak, Extension Water Resources Engineer

Average added profit: 
$20.12/acre
(2.1-2.6 inch water savings)

One of the challenges to irrigated crop production in the Midwest is the limited adoption of newer technologies to help farmers better manage irrigation, conserve water and energy, and increase crop water use efficiency. Adoption of accurate, practical, and economical tools can help growers make better decisions and improve irrigation efficiencies through optimum irrigation timing and amount.

To encourage growers to adopt these newer technologies, a network of growers, researchers, Natural Resources Conservation Service (NRCS) staff extension personnel, local Natural Resources Districts (NRDs), and other state and federal agencies was developed. Based on several meetings with the NRDs, growers, and crop consultants, it was decided that a network should be established to enable and/or enhance communication and partnership among different agencies and growers.

This network could establish and/or improve communication and the exchange of ideas among institutions as well as provide a means for individuals to learn from each other while working toward a common goal of conserving and protecting precious water resources for today and future generations.

The Nebraska Agricultural Water Management Demonstration Network (NAWMDN) is designed to establish a partnership among growers, crop consultants, NRDs, NRCS, irrigation districts, and University of Nebraska-Lincoln Extension to increase water use efficiency in crop production. The primary goal of the Network is to enable transfer of high quality research-based information to Nebraskans through on-farm demonstrations, fostering the adoption of new irrigation management technologies and methods that increase irrigation efficiency and reduce energy consumption. The demonstration network is enhancing communication and information exchange between farmers, researchers, NRCS, UNL Extension, NRDs, and other state and federal water regulatory agencies. The demonstration projects are supported by scientific field research and evaluation projects at UNL's South Central Agricultural Laboratory (SCAL) near Clay Center.

Irrigation Management Tools

Two primary tools adopted by the Network are ETgages and Watermark sensors. The ETgage is used to estimate crop water use from reference evapotranspiration and crop coefficient information. The Watermark sensors are electrical resistance-based sensors used to monitor available water in the crop root zone over time. Network participants learn how to use these tools to make better-informed irrigation decisions. In addition to the demonstration projects, the information is delivered to network participants through field days, seminars, workshops, publications, media reports, etc. More detailed information on the network goals and objectives and progress can be found at: http://water.unl.edu/cropswater/nawmdn.

Network Development, Producer Savings

The Nebraska Agricultural Water Management Demonstration Network was initiated in 2005 with 15 growers. By 2008, the number of active participants had increased to more than 300 growers. Due to information taught through the Network, participants are changing how they manage irrigations. The network is having significant impacts in terms of reducing the water withdrawal for irrigation from the aquifer and energy used for pumping irrigation water.

The following sections provide a brief description of the Network's impact on water savings and summarize partner feedback.

Partners Surveyed

In 2006, Extension Educators sent out 40 surveys and had a return rate of 75%. Most cooperators were from the Upper Big Blue NRD and a few were from the Little Blue NRD. Of those responding, twenty-five (83.3%) were producers and five (16.7%) crop consultants/other (students/or no response).

In 2007 Extension Educators sent surveys to 89 producers actively involved in the Network. Fifty surveys were completed and returned for a response rate of 56%. Twenty-nine cooperators (58%) were from the Upper Big Blue NRD and 19 (38%) were from the Little Blue NRD. Of those responding, forty-five (90%) were producers and five (10%) were crop consultants/other.

In 2007, cooperating producers and consultants had approximately 117,000 total irrigated acres with approximately 80,000 in corn and more than 37,000 in soybeans. Producers were asked to estimate their irrigation for corn and soybeans for 2006 and 2007 (Table 1).

Estimated annual irrigation applied by NAWMDN survey resondents in 2006-2007.

Year

Crop

Average Application
(in inches)

Range of Application
(in inches)

2006

Corn

9.3”

4.8 – 14.0”

2007

Corn

5.2”

2.3 – 10.0”

2006

Soybeans

7.5”

2.0 – 11.1”

2007

Soybeans

3.5”

1.3 – 9.5”

Partners Identify Water Savings Averaging $19.40-$24.00/acre

When asked, "Did using the equipment or the NAWMDN information influence you on the amount of irrigation water to apply?" almost 100% said it had.

Producers were asked to estimate their water savings for corn and soybeans in 2007. Estimated water savings for corn ranged from 0 to 7.5 inches with an average of 2.6 inches while soybean water savings ranged from 0 to 4.8 inches with an average of 2.1 inches. With 2007 diesel fuel prices of $3.80 per gallon, the water savings of 2.6 and 2.1 inches represent $24.00/acre and $19.40/acre, respectively. This savings was calculated based on the assumption that the pumping plant was operating at the Nebraska Pumping Plant Performance Criteria. The pumping lift was assumed as 150 ft, the pump pressure was assumed as 50 PSI, and the system flow rate was taken as 800 GPM. The ownership costs of the system and other operating costs are not included in the pumping cost calculations. Also, the energy required to power electric generators or hydraulic pumps to operate the center pivot drives are not included in the pumping cost estimates.

In 2006, the survey participants represented about 60,000 acre of croplands. The water saving that was reported by the network participants ranged from 1.0 inches to 3.5 inches for corn and soybeans with an average of 1.7 inches for both crops. With 2006 diesel fuel prices of $3.80 per gallon, the water saving range of 1.0 inches and 3.5 inches represents a savings of $9.20/acre and $32.30/acre, respectively, due to reduced irrigation water pumpage. The average water savings of 1.7 inches is associated with a $15.70/acre net benefit to the growers.