Research

• Long-term Tillage Plots
• Conservation Research
• Constructed Wetlands
• Stiff-grass Hedges
• Riparian Buffer Strips

Research projects, located in many areas of the 300 acres of the farm, range from early planting of soybeans to residential wastewater treatment using a constructed wetland. After the Agricultural Engineering Department (now Biological Systems Engineering) took over the operation of the farm in 1966, the principle research dealt with soil and water conservation using terraces and conservation tillage practices. The late Howard Wittmus pioneered the use of parallel, steep, back-slope terraces with drain tile outlets.

Research on and demonstration of structural conservation practices have included different terrace layouts, terrace types, terrace outlets, and drainage systems. Woodland and windbreak renovation and establishment practices are being evaluated, using both the farmstead and the streamside riparian areas.

Some production related research is conducted using strip trials, just as many farmers would do on their own farms. Hybrid and variety testing, row spacing and population studies, planting date comparisons, and fertilizer trials are examples of some of the cultural production practices being evaluated. Results from this type of applied research are being used to fine-tune the farm's general crop production, to demonstrate aspects of the farm, and to support Extension programs.

Studies by other departments included work on forestry (including woodlot management and development of a black walnut enterprise), control of pocket gophers, field scouting of insects, and basic studies on coyotes.

The faculty and staff of Biological Systems Engineering conduct a variety of experiments including tillage and erosion studies, stiff-grass hedges and riparian buffer zones and runoff monitoring stations. Machine vision, Global Positioning Systems and other technologies are used in the research. Students are often involved in these projects and gain valuable educational and professional experience.

No-till and other conservation tillage systems have long been promoted for soil and water conservation. Research plots were established in 1981 to evaluate six different tillage systems in a soybean/grain sorghum rotation using the same tillage system year after year. The data from these plots and the experiences gained in the management required to make no-till and reduced tillage systems successful have provided valuable support for Extension programs.

These dryland production plots have been maintained ever since 1981 and are showing that with proper management, no-till is the most profitable tillage system. The yields, listed below for this long-term tillage system study on the Rogers Memorial Farm, show that even with the drought conditions of 2000, no-till was the hands down winner.

Contact Paul Jasa for more information.

Tillage Comparisons
Conservation research includes comparison of tillage systems in a grain sorghum-soybean rotation, a corn-soybean rotation, continuous corn, and continuous soybeans. The tillage systems on these plots were established in 1981, providing valuable data on the long-term effects of tillage practices. As with many no-till studies, the soil building benefits of no-till were not readily seen in the first few years of research. Over the years, rainfall simulators have been used on other plots to evaluate erosion and runoff from different tillage systems and to investigate water quality concerns. A solid-set irrigation system has been used to evaluate irrigation scheduling methods, deficit irrigation, and impacts on water quality.

Soil Moisture Conservation
The weed control program includes early preplant residual applications, herbicide treatment of the wheat stubble, and no row crop cultivation or tillage. Postemergence treatments (as necessary), and some fall applications are also effective tools used in the weed control program, particularly for perennial weeds. With this integrated approach there has been little need for burndown herbicides. Correct weed identification and herbicide selection, combined with proper timing and uniform allocation, are keys to making the weed control program successful.

Soil Fertility Program
This program is based on soil tests and realistic crop yield goals. The crops of wheat, corn, and grain sorghum receive an in-furrow application of liquid 10-34-0 at planting time as a nitrogen starter and phosphorous source. Anhydrous ammonia is the primary nitrogen source for corn and grain sorghum production, and is usually knife applied in the fall to minimize disturbing the wet soil and residue in the spring. Dry ammonium nitrate is broadcast on the wheat in the spring. Lime is surface applied periodically in the fall at low rates to correct pH problems without tillage incorporation. No fertilizer is applied for soybean production.

"Utilizing wetlands to treat municipal wastewater isn't new, but using the idea for single-family households is unique," says faculty member Wayne Woldt. He has been studying the use of a constructed wetland to filter rural household wastewater as a system that may someday replace the leaky laterals and unsightly lagoons found on many farmsteads and acreages.

It is estimated that 2/3 of the soils in the United States are unsuitable for traditional drainfield systems installed with septic tanks. In these areas, poor soil characteristics allow pathogens and nutrients in sewage to become pollutants. Lagoons are currently an option in these areas, but are often seen as undesirable.

Constructed wetlands work through subsurface flow: effluent from a septic tank is filtered through pea gravel and plant roots. Wetland cells are typically installed on a gradual slope (.5%) and the filtered wastewater from the lower end can be drained into a wildlife habitat area or used for other purposes depending on local and state regulations.

Research in Nebraska and at Texas A & M University has shown that this method can: reduce the solids in wastewater by up to 68%, cut bacterial oxygen demand by up to 56%, and reduce fecal coliform by up to 94% and ammonioum by 41% when compared with a typical drain field fed from a septic tank. The quality of the treated wastewater was as good as that in a drainage field, is less expensive depending on soil type and site condition, more reliable, and less unsightly. Future research will determine if the wetland will operate successfully following the severe winter weather of Nebraska.

Wayne Woldt is the faculty member working on this research.

No-till farmers still deal with erosion during heavy rains. While the residue left on the fields helps hold the moisture, it can't hold back heavy runoff like a terraced field. Dean Eisenhauer has been working with stiff grass hedges as a way to stabilize soil, even on steep slopes, to prevent washouts and rills caused by heavy rain.

Stiff-grass hedges were planted on the Rogers Memorial Farm in 1998 in parallel rows following the contour of the land. They were spaced according to the width of the planter and row spacing, so the hedges are easy to farm between. The 3.5-foot wide hedges were seeded with switch grass. Once the grass was established, findings indicated that runoff was slowed and soil was deposited in all but the most concentrated flow situations. Researchers have found that under no-till conditions, plots with these hedges averaged 53% less soil loss than similar plots without the barriers.

The Natural Resources and Conservation Service (NRSC) is currently in the process of writing standards for the use of grass hedges that will specify the width and spacing of the hedges according to the slope and soil conditions.

Dean Eisenhauer is the faculty member working on this research. He is assisted by John Gilley and Tom Franti.

A riparian buffer strip is located along the creek on the eastern edge of the farm.

Riparian buffers are native grass strips with trees and/or shrubs planted along water bodies. Like other conservation filter strips, they trap fertilizers, pesticides, bacteria, pathogens, and heavy metals to minimize the chances of these potential pollutants reaching surface or ground water sources. Removal of these pollutants is most effective when they are bound to soil and not left in solution. In addition, riparian buffers also help stabilize streambanks, improve wildlife habitat, improve the scenery, and protect aquatic life in small to mid-sized streams.

Healthy riparian areas can reduce flooding by preserving a stream's natural characteristics. The roots of the plants increase water infiltration. Plant transpiration takes up the water, nutrients, and chemicals in the buffer soil profile, thereby "using" pollutants in storage.

The riparian buffer zone on Rogers Memorial Farm was planted with Switchgrass, Big Bluestem, and Indiangrass in 1998. The zone is about 45 feet wide between the tree line and the field and runs for approximately 500 feet. Maintenance includes:

• frequent inspections, especially after intense rains or long runoff events, and removal or regrading of accumulated sediment
• minimizing the development of erosion channels --repair and reseed immediately
• Reseeding and interseeding bare spots
• Mowing (to a 6-inch height) and removing vegetation regularly, 2-3 times a year if growth is vigorous
• testing soil periodically to assure continued plant health and vigor
• control of unwanted trees, brush, and noxious weeds

Dean Eisenhauer is the faculty member directing this reserach. He is being assisted by Tom Franti.

Department of Biological Systems Engineering