ArkValley Irrigation Grant Final Report

• Project Type: Ag/Muni Grant
• Applicant: Colorado State University Cooperative Extensions
• Project Name: Improvement of Irrigation Technology in Arkansas River Valley
• Title: Demonstrations of Irrigation Technology to Improve Crop Yields, Returns and Water Quality in the Arkansas River Valley of Colorado Summary and Conclusions
• County: Larimer
• Water Conservation - Doc Type: Final Report

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United States
Department of
Agriculture

Agricultural
Research
Service

Pacific West Area

U.S. Salinity Laboratory
450 W. Big Springs Road
Riverside, CA 92507-4617

Tel. [phone]
Fax, 909-342-4962
Email. [e-mail]

November 8,1996

The recommendations that you have given the farmer of field # 2 are appropriate and
good ones. By replacing the sprinklers with drop-tubes, foliar burn can be avoided. Another aid
would be to use the fresh water from the ditch that is available during the early season for the pre-
plant and seedling establishment irrigations and to then switch to the saline well waters later as the
surface water supply is exhausted and the plants are in a more salt-tolerant growth stage. Planting
in beds will improve soil aeration and reduce the crusting and thus aid plant emergence--provided
you can get the beds to "wet-up"; this may be a bit tricky unless you provide frequent "dams" in
the furrows to impound the water to get it to a proper height for bed-subbing. Unless the field is
well graded, you may not get good water-depth control without the creation ofmicro-, check-
dams in the furrows. Irrigating in every other furrow will help minimize the level of salinity in the
beds, but will accumulate the salts in the vicinity of the "dry-furrow". It would be good if you
could irrigate in all furrows, once the plants are well established. Otherwise make sure you get
good leaching of this soil area before the next crop is planted. Crops with the most tolerance to
foliar burn should be grown. The data on this is quite limited; I don't have much information to
provide you in this regard-sorry.

These same general recommendations would help farmer # 4, as well, But he needs to see
ifhe is under-irrigating or if the subsurface-drainage is inadequate there. I think he needs to grade
the field to eliminate the uneveness in the soil micro-topography.

Farmer # 1 has a well water of very high salinity, as I recall. But foliar bum is not a factor
there, since he is irrigating by cablegation via furrows. He should limit his crops to salt-tolerant
ones and focus on creating better seedbed conditions for seedling establishment, on reducing soil
crusting and preventing high levels of salinity in the vicinity of the seeding. You know all the
tricks to do this.

Hope these data and suggestions help. Please pass this information on to Lorenz. I
enjoyed our trip and chance to work with you and Lorenz, I look forward to undertaking more
"experitions" to Colorado and some time for hunting and fishing there also.

Sincerely,

~~d~