January 21, 1994
Jim Valliant, Regional Irrigation Specialist, Colorado State University, Cooperative Extension

For Immediate Release...

SURGE IRRIGATION SAVES WATER WITH TOP YIELDS

Again in 1993, surge irrigation saved 12.1 and 23.8 percent irrigation water when compared to conventional furrow irrigation on two corn irrigation demonstration sites under the Patterson Hollow Water Quality Project. "These savings amount to 5.2 and 6.6 inches per acre while producing 164.2 and 151.1 bushels per acre, the same as conventionally irrigated corn at one site and, for the first time in three years of testing, less than conventionally irrigated corn at the second site", said Jim Valliant, irrigation specialist for Colorado State University Cooperative Extension in southeast Colorado.

At the North Site, surge irrigation produced 164.2 bushels compared to 162.5 bushels per acre when conventionally irrigated while using 37.3 inches of irrigation water, 5.2 inches less than the 42.5 inches used on the conventionally irrigated area. Irrigation efficiency was improved to 4.4 bushels per inch of water with surge from 3.8 bushels per inch on conventionally irrigated corn.

Runoff amounts were similar with 8.4 and 8.5 inches per acre on the surge and conventional areas respectively. As a result, similar amounts of total dissolved solids, nitrates and sediment were produced by the two methods of irrigation.

Based on a three-year average, the surge irrigated area produced 184.9 bushels while using 32.7 inches per acre of irrigation water as compared to 181.7 bushels and 39.2 inches, or 6.5 inches per acre more irrigation water, on the conventionally irrigated area. With 0.5 inches less runoff, 5.6 compared to 6.1 inches per acre, surge irrigation reduced salts from 656 pounds per acre to 588.

At the South Site, the surge irrigated corn produced 151. 1 bushels per acre compared to 159.7 bushels produced on the conventionally irrigated area. "This is the first time in three years of testing that surge irrigation has produced lower yields than conventional irrigation", Valliant said. Using 6.6 inches per acre less irrigation water, 21.3 compared to 27.9 inches per acre, surge irrigation increased irrigation efficiency to 7.1 bushels per inch from 5.7 bushels per inch.

Runoff on the South Site was reduced by 32.1% by surge irrigation, from 7.4 to 5.0 inches per acre. As a result, the amounts of total dissolved solids or salts and nitrates flowing off the area was significantly reduced. Salts were reduced from 546 to 400 pounds per acre, nitrates were reduced from 4.9 to 4.0 pounds per acre. Sediment loss was similar on both areas.

Based on two-years results at the South Site, surge irrigation produced 189.0 bushels using 22.5 inches of water compared to conventional irrigation which produced 194.2 bushels and used 29.8 inches, or 17.3 inches per acre more water. As a result, surge irrigation improved irrigation efficiency from 6.5 to 8.4 bushels per inch of irrigation water.

Surge irrigation reduced runoff an average of 2.0 inches per acre when compared to conventional irrigation, from 7.1 to 5.1 inches per acre. Salts in the runoff water were reduced from 625 to 475 pounds per acre while nitrates were reduced from 4.6 to 3.5 pounds per acre.

"Surge irrigation is helping the Patterson Hollow Water Quality Project to achieve its goals which are to improve the quality of water returning to the river and the groundwater basin while improving irrigation efficiency and maintaining yields and returns", Valliant concluded.