What is in this article?:
- Distribution uniformity an irrigation key
- Irrigation scheduling
- Even distribution of irrigation water can mean a combination of high tech wizardry and low tech, hands-on tweaking.
David Jamison, senior agronomist with PureSense in Fresno, uses a moisture probe to check how far into root zone water is seeping.
Getting even distribution of water to the roots of peach trees in a given orchard can mean a combination of high tech wizardry and low tech, hands-on tweaking.
That was well demonstrated at Fresno State University in an irrigation seminar that showcased the use of probes that go deep into the ground and can provide data over cell phones or laptops.
But those probes shared the stage with less sophisticated tools that included pliers and “goof plugs” that are used for irrigation lines after a test with a pressure gauge.
Speakers at the Center for Irrigation Technology workshop told how a simple adjustment to valves in an orchard on the campus farm – taking just minutes -- brought an 8 percent improvement in the even distribution of irrigation water, moving the uniformity percentage from 84 percent to 92 percent.
That means water savings and more efficient water use.
The initials “DU” were tossed about freely. That’s not a reference to Ducks Unlimited but to “Distribution Uniformity,” a measure of how evenly water soaks into the ground across a field during irrigation.
Kaomine Vang, CIT project manager, and Bill Green, education manager of the center’s advanced pumping efficiency program, talked of some of the challenges in a 12-acre orchard on campus where July Flame Peaches have been grown for about a decade.
They told how tests were conducted to show variability in water pressure on parts of the orchard that showed that simply turning the knobs on valves that deliver water to the orchard greatly improved efficiency of the system.
The two said the problem was that someone was turning two pressure regulating valves open or closed and had opened one of them all the way. Green said it might be wise to remove the handles once adjustments are made.
Both men said that challenges in the orchard include the fact that water that comes from a canal is low in pH and does not seep deeply into the sandy soil. That has meant some standing water that draws the attention of mosquito abatement officials, they said.
Green said some efforts have been made to improve permeability by adding limestone and gypsum to the soil.
David Jamison, senior agronomist with PureSense in Fresno, explained how moisture sensors are buried in the soil as deep as 5 feet to determine moisture levels that are shown on graphs. He also used a metal soil probe that he thrust into the soil to check the depth of moisture.
Jamison said it is important to survey the field and irrigation layout before putting the automatic sensors in place, taking into account soil types, commodity differences and other issues.