Effect of Optimal Water Management for Sustainable and Profitable Crop Production and Improvement of Water Quality in Red River Valley

Effect of Optimal Water Management for Sustainable and Profitable Crop Production and Improvement of Water Quality in Red River Valley

Summary

This project focused on optimal water management on production land, with drainage being applied during wet conditions and subirrigation being used during drought condition. In the fall of 2011, we installed 24 observation wells, took 48 soil profile samples, and conducted soil physical and chemical analysis. In the spring of 2012, we installed weather stations and soil moisture sensors in four corn fields; all four fields are located within two miles proximity and have similar soil types. Water quantity and quality monitoring equipment were also installed inside and outside the fields, and along the drainage ditch. As a result of the severe drought conditions in 2012, drainage and controlled drainage practices were not used, instead, subirrigation became the focus. We started testing the subirrigation system on June 15, 2012, a total of 5.4 million gallons of water was applied to one 94 ac corn field. The same subirrigation system was then relocated to a 160 ac sugarbeet field, and 18.6 million gallons of water was applied. This severe drought condition resulted in a water table below 2 m deep, and a moisture condition in the root zone that was far below the 50% available water range. Hence, any water applied to the field was taken up by the crops immediately. The subirrigation practice resulted in a 46% yield increase for corn and 23% yield increase for sugarbeet. Three field tours and several individual tours were given to personnel from federal, state, and county agencies, academia, industry, and landowners in both MN and ND.

Objectives/Performance Targets

In 2012, we worked on the following objectives:
1. Optimize water management through a subirrigation system on one corn field;
2. Compare yield differences between undrained, free drainage, controlled drainage, and controlled drainage plus subirrigation fields;

3. Monitor water quality (e.g. nitrate, phosphorus, turbidity, salinity, etc.) in the upper and down streams of the subirrigation intake and drainage outlet structures.
4. Measure crop evapotranspiration rates and soil moisture changes in each of the four fields (e.g. each field utilizes a different water management system); and
5. Estimate the total annual water balance in the undrained, free drained, control drained, and control drained plus subirrgated fields.

Accomplishments/Milestones

The project was officially started in September 2011, however many field activities actually began in April 2010. Four production fields in Clay County, MN were selected for the experiment. The fields are located next to each other and along the same drainage ditch. Four water treatments, undrained (UD, 40 ac), free tile drainage (FD, 60 ac), controlled drainage (CD, 43 ac), and controlled drainage plus subirrigation (SI, 51 ac) were applied (Figure 1).

In each field, three pairs of observation wells (2 m depth) were installed in November 2011, and are randomly located in the upper, middle and bottom part of the field. For each pair, one well is located close to the tile and the other is centered between two tile lines. A water level transducer was installed in each of the 24 wells, which automatically records water level changes every 30 min.

Soil profile samples were taken when installing the observation wells. Soil physical and chemical properties for 7 depths (0-15, 15-30, 30-61, 61-91, 91-122, 122-152, and 152-183 cm) were determined in the labs since fall 2011. These properties are bulk density, saturated hydraulic conductivity, particle size distribution, soil characteristic curves, electrical conductivity (EC), sodium adsorption ratio (SAR), and calcium (Ca), magnesium (Mg), and sodium (Na) concentrations. Average particle size distributions for the top and bottom 1 m soil are plotted in Figure 2. Soil chemical concentrations for Ca, Mg, and Na as well as EC and SAR for top and bottom 1 m soils are plotted in Figure 3 and 4.

Water quality in County Drainage Ditch 39 is being monitored in order to determine whether SI can improve water quality in the surface water. Water depth, turbidity, electrical conductivity and pH were measured continuously at the upper and down streams of the SI field. Water samples were also collected weekly at the upper and down streams along with at the three control drainage flow structures, located near the outlet for the CD/SI field. Chemical analysis of these water samples, in the upper and lower streams, is shown in Figure 5. The results indicated that, except for the EC values, the SI process improved the water quality for pH, PO4-P, and NO3-N through impoundment or subirrigation.

Water balance components, including rainfall, snowfall, snow equivalent water content, evapotranspiration (ET), soil moisture changes, surface runoff, drainage outflow, subirrigation amount, and water level changes are measured in the field continuously for the entire duration of the project. V-notch weirs with standard 90 degree angle were constructed and installed at the culvert. Water level transducers are used to measure the water level changes. However, due to the drought conditions in 2012, surface runoff was never generated and therefore, no surface runoff was measured.

At the SI site, ET is measured by three methods, eddy covariance (Eddy), soil moisture deficit (SMD), and photosynthetically active radiation (PAR). However, at the CD site, ET is only measured by SMD method and at the UD and FD sites, ET is only measured by the PAR method. All weather stations and soil moisture sensors are setup to run in the winter time, so they can be remotely accessed through either cellular or radio devices.

A research proposal to North Dakota Water Resources Research Institute (WRRI) by graduate student, Kelsey Kolars, was submitted in November 2012 and is funded for the water balance investigation in 2013. Kelsey also submitted an abstract on ET comparison for the three methods and four water treatments to the American Society of Agricultural and Biological Engineers (ASABE) annual meeting. An oral presentation will be given in July 2013. A full paper will be submitted in June 2013.

Subirrigation is relatively new in this region. Many land owners would like to subirrigate their land if water sources are available, but the methods, techniques, and considerations for subirrigation practices in the Red River Valley are not available. An abstract on these topics was accepted by the ASABE annual meeting. An oral presentation and a full paper will be given in summer 2013 by graduate student, Kyle Horntvedt. Kyle also submitted a research proposal to the ND WRRI on “Measurement and modeling of soil moisture changes for subsurface drained and subirrigated fields in the Red River Valley” in November 2012. His proposal is also funded and he will compare measured soil moisture changes with modeled result from Hydrus 2D and DRAINMOD.

A subirrigation system was put into use on June 15, and stopped on July 19. A total amount of 5.4 million gallons water was added to the 94 ac field (the SI field is only 51 ac), resulting in 2.12 in of subirrigation application. A temporary dam was constructed in the ditch to hold the water; a 15 hp variable rate sump pump was used to pump the water from the ditch to the top of a storage tank located at the ditch bank. The tank is needed to create elevation difference so that water can be delivered to the top elevation point at the southeast corner of the field through gravity. A profile and cross-section view of the SI system is shown in Figure 6. The SI practice has resulted in 46% corn yield increase comparing to the corn in the CD field.

Therefore, we can conclude that crop yield is increased, and water quality is improved due to the SI practice using the data in 2012, which occurred during severe drought in the Red River Valley region.

• Figure 3. Chemical properties for top 1 m soil for the four experimental sites. The vertical dashed lines separate the four sites, with SI – subirrigation, CD – controlled drainage, UD – undrained, and FD – free drainage
• Figure 2. Particle size distribution for top 1 m (left) and bottom 1 m (right) soils from four experimental plots
• Figure 4. Chemical properties for bottom 1 m soil for the four experimental sites. The vertical dashed lines separate the four sites, with SI – subirrigation, CD – controlled drainage, UD – undrained, and FD – free drainage.
• Figure 5. Upper and lower stream water sample analysis for (a) electrical conductivity (EC), (b) pH, (c) phosphorus (PO4-P), and (d) nitrate (NO3-N) at the surface ditch.
• Figure 6. Top view (top), and cross-sectional view (bottom) of the subirrigation system setup.
• Figure 1. Experimental layout

Impacts and Contributions/Outcomes

This project is to evaluate whether optimal water management through drainage and subirrigation can be used to increase farmer’s profit and improve water quality for the entire community. However, many landowners living near the experimental site were not aware of the benefits, but concerned more about potential negative impacts due to impoundment in the ditch. A public hearing for temporary impoundment of drainage waters was held on June 4, 2012 in Moorhead City Hall. A total of 21 people attended the meeting. The research team used this meeting as a good opportunity to address the benefit of the project for the landowners and the importance of drainage water management.

The Extension Services of NDSU, SDSU and the University of Minnesota held two tile drainage design workshops in Wahpeton, ND on February 21-22 and February 23-24, 2012. About 80 farmers and other people associated with agriculture attended each workshop. The landowner, Mr. Zimmerman, was a featured speaker on a farmer panel at each workshop where the subirrigation system was explained. In addition, one of the design sessions included in each workshop was on conservation drainage. Mr. Zimmerman has also made several office visits with NDSU Extension engineers to develop the design for the subirrigation pumping station. On November 7, 2012, 15 ND NRCS professionals visited the site during its Drainage Water Management meeting. On June 8, 2011, the North Central Extension Research Activity 217 multistate committee on “Drainage design and management practices to improve water quality” visited the field with 30 attendees from 9 states and Canada as well as NRCS representatives. On September 7, 2011, Clay County Soil Conservation organized a tour with 35 attendees. On October 6, 2011, we hosted a controlled drainage tour and meeting for 7 professionals from 3 Canadian provinces. The SARE site was included in the drainage tour. Also, we often have individual visitors stop by the site for consulting and are accompanied either by the research team members or the landowner.

Project blog: http://aben-saregrant-ndsu.blogspot.com/
This blog was created with the intent to keep the public updated and informed about the research activities. Pictures and videos of field/lab experiments, short descriptions of our research activities, and team member’s accomplishments/awards, will be periodically updated at the blog. It also creates an open communication among professionals, researchers, farmers, and the general public.

Collaborators: