Malheur County Best Management Practices


	Soil Water Conservation District	Malheur Experiment Station

in cooperation with the Malheur Watershed Council
and the Owyhee Watershed Council

1. Mechanical straw mulching is a practice that can greatly improve yields and help control soil erosion, water runoff, and water infiltration of the soil. It is a practice that is and will be very important with the upcoming water standards to be placed in effect soon. Here's a link to information regarding mechanical straw mulch: Cost and Benefits of Mechanical Straw Mulch Application to Irrigation Furrows

2. Polyacrylamide (PAM) is a synthetic water-soluble polymer than when added to irrigation water can greatly reduce soil erosion and increase water infiltration. Here's a link for application and information of this BMP: Benefits and Costs of Applying Polyacrylamide (PAM) in Irrigated Furrows.

3. The Conversion of Furrow Irrigation to Drip Irrigation can greatly improve yields and help with irrigation management. Click on above link for more information to see if Drip is for you.

4. Comparison of Mechanical Straw Mulch and Polyacrylamide

Trenkel, J., D. Burton, and C.C. Shock. 1996. PAM and/or low rates of straw furrow mulching to reduce soil erosion and increase water infiltration in a furrow irrigated field, 1995 trial. OSU, Malheur Experiment Station. Special Report 964: 167-175.
Shock, C.C., E. B. G. Feibert and L. D. Saunders. 1997. A comparison of straw mulching and PAM for potato production. OSU, Malheur Experiment Station Special Report. 978:71-78.
Shock, C. C., J. Zattiero, K. Kantola, and L. D. Saunders. 1995. Comparative cost and effectiveness of polyacrylamide and straw mulch on sediment loss from furrow irrigated potatoes. OSU, Malheur Experiment Station Special Report 947:128-137.

5. Surge Irrigation. With the upcoming standards regarding water quality, the use of best management practices in fields to reduce soil loss, nutrient loss, and water usage, is becoming very important. Studies done at the Malheur Experiment Station on surge irrigation have shown that surge irrigation is an effective tool to improve irrigation efficiency, reduce water runoff, and reduce sediment loss.

Surge irrigation uses a surge controller butterfly valve placed in the center of the top of the field with gated pipe leading out of the valve going both directions along the top of the field. In fields with some side slope, the surge valve can be placed in the corner of the field, and extra pipe used to distribute the water. The valve works by oscillating water from one side of the valve to the other at decided intervals. (In conventional irrigating systems the water flows continuously for the irrigation set.) The alternating flow of water on each side of the valve causes an intermittent wetting and soaking cycle in the irrigated furrow. See Cost and Benefits of Surge Irrigation.

6. Water conservation is becoming a major issue with upcoming TMDL regulations being placed into effect and the continuous possibility of a drought year on the horizon. Dealing with drought is a report that discusses suggestions and irrigation techniques for conserving water.

7. Nutrient Management

8. Filter Strips
A filter strip is an area of grass or other permanent vegetation used to reduce sediment, organic particulates, nutrients, pesticides, and other contaminants from runoff and to maintain or improve water quality. It also has other benefits such as providing a habitat for wildlife and beneficial insects, watershed protection, aesthetics, and it protects riparian forest buffers from erosion and sediment.

9. Underground Outlets

10. Sediment Basins and Tail Water Recovery Systems

Some of the first sedimentation basins promoted by the SCS in the county were more demonstration-education systems. They demonstrated to grower the dimensions of their irrigation-induced erosion problem. Many functional sedimentation basins with pump back features were built in the late 1980's and 1991 and 1992 with active participation of the SCS, ASCS, and SWCD.

11. Turbulent Fountain Weed Screens

With trash in the water, gates in gated pipe have to be set wider open and larger siphon tubes have to be used to help assure that the trash passes through the gate or tube. Under the circumstances of trashy water, more water has to be set on a field than is really necessary, hence more water is present in many furrows than required to irrigate the row. The extra water promotes irrigation induced erosion and excessive leaching of nitrate to groundwater. The cleaner the water, the greater accuracy that gates and siphon tubes can be set, with assurance that the furrow irrigation will continue to run as set.

Herb Futter of the SCS visited the ARS field day in Kimberly, ID and was impressed by at turbulent fountain weed screen (bubbler weed screens) demonstrated by J.A. Bondurant. Mr. Bondurant donated a portable weed screen to Herb and he installed it at the Malheur Experiment Station through the cooperation of Dwayne Buxton. The second screen at the station was on the main water supply of the station, and it was excellent for demonstration purposes, but it was insufficient in allowing adequate water to irrigate the station. During the winter of 84-85 the water delivery system was rebuilt with a much larger weed screen on the station. In 1986 three mobile small screens built and were installed at the station on gated pipe delivery lines. These smaller screens helped show the advantages. Adoption of weed screens after Herb Futter used the screens at the Malheur Experiment Station in a 1985 Field Day to promote the use of bubbler weed screens to remove weed seed and trash from irrigation water. Growers started building and installing weed screens on their own, with fabrication by local irrigation dealers. Especially noteworthy were the efforts of Dale Cruson, who gave a big boost to screen adoption by manufacturing many of the screens.

12. Crop Sequencing to Control Surface Irrigation Erosion

13. Conversion of Furrow Irrigation to Sprinkler Irrigation

14. Laser Leveling

Prior to the 1980's, fields had been leveled by conventional means. Fields were surveyed, staked, and soil was moved about within a field by farm tractor powered equipment. Fields with slopes of 0.6 to 0.7 or more feet per hundred feet required too much water to irrigate due to excessive runoff and resulted in too much soil erosion. Fields with slightly irregular slopes had parts which required long irrigation durations, and also had flat spots with excessive water infiltration which resulted in excessive deep leaching.

Dressing fields with laser leveling to a slope of 0.3 to 0.4 feet per hundred feet provided immediate benefits for surface irrigation. Herb Futter was able to show less soil was lost from the field and the field irrigated much more uniformly. The uniformity of irrigation allowed for the conservation of water, less leaching in the wetter parts of the field, and improved crop performance. During the early 1980's ASCS would not fund laser leveling, but starting in the latter half of the 1980's they did participate in cost share based on Herb Futter's results.

15. Gated Pipe

Gated pipe was introduced to allow more uniform irrigation on many surface irrigation sites. The water set in each furrow can be less than with siphon tubes, and allows surface irrigation with conservation of water, reduced irrigation induced erosion, and less leaching potential. Gated pipe also facilitates the eventual adoption of surge irrigation.

Gated pipe was first used in a substantial way in Malheur County in 1977, a year of severe drought. The 80 miles of fiberglass pipe arrived too late to do much good that year. The project was promoted by the SCS and was cost shared by the ASCS. The fiber glass pipe proved to have poor durability outdoors in the sunlight.

More durable plastic gated pipe was introduced and supported by cost share programs.

16. Irrigation Scheduling